JPH08152302A - Thickness discriminator - Google Patents
Thickness discriminatorInfo
- Publication number
- JPH08152302A JPH08152302A JP6295006A JP29500694A JPH08152302A JP H08152302 A JPH08152302 A JP H08152302A JP 6295006 A JP6295006 A JP 6295006A JP 29500694 A JP29500694 A JP 29500694A JP H08152302 A JPH08152302 A JP H08152302A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic flux
- inspected
- alternating magnetic
- circuit
- thickness
- 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.)
- Granted
Links
- 230000004907 flux Effects 0.000 claims abstract description 34
- 230000005540 biological transmission Effects 0.000 claims abstract description 14
- 230000010363 phase shift Effects 0.000 claims abstract description 11
- 238000001514 detection method Methods 0.000 claims description 38
- 238000000034 method Methods 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 abstract description 49
- 239000002184 metal Substances 0.000 abstract description 49
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 18
- 229910052782 aluminium Inorganic materials 0.000 description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 13
- 238000010586 diagram Methods 0.000 description 9
- 229910052742 iron Inorganic materials 0.000 description 9
- 238000007689 inspection Methods 0.000 description 7
- PMVSDNDAUGGCCE-TYYBGVCCSA-L Ferrous fumarate Chemical compound [Fe+2].[O-]C(=O)\C=C\C([O-])=O PMVSDNDAUGGCCE-TYYBGVCCSA-L 0.000 description 3
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000009738 saturating Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
(57)【要約】
【目的】本発明は、被検査体、例えば金属板の厚さを複
数に弁別する厚さ弁別装置に関し、特に非磁性の金属板
の厚さを高精度に弁別する。
【構成】被検査体透過前後の交番磁束の位相ずれに基づ
いて、被検査体透過前後の交番磁束の位相ずれとともに
被検査体を透過したことによる交番磁束の減衰のレベル
に基づいて、被検査体の厚さを複数に弁別する。
(57) [Summary] [Object] The present invention relates to a thickness discriminating apparatus for discriminating a plurality of thicknesses of an object to be inspected, for example, a metal sheet, and particularly discriminating the thickness of a non-magnetic metal sheet with high accuracy. [Structure] Based on the phase shift of the alternating magnetic flux before and after passing through the inspected body, the phase shift of the alternating magnetic flux before and after passing through the inspected body and the level of attenuation of the alternating magnetic flux due to transmission through the inspected body Discriminate the body thickness into multiple.
Description
【０００１】[0001]
【産業上の利用分野】本発明は、被検査体、例えば金属
板の厚さを複数に弁別する厚さ弁別装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness discriminating apparatus for discriminating a plurality of thicknesses of an object to be inspected, for example, a metal plate.
【０００２】[0002]
【従来の技術】従来より、上記のような弁別装置が広範
な分野で使用されている。ここでは、その一例として金
属板の２枚重ねを検出する装置の例について説明する。
図６は、金属板２枚重ね検出装置の一例を示す模式図で
ある。例えば金属板を曲げ加工し、あるいはその金属板
に孔あけ加工するラインの最上流側では、多数枚積み重
ねられた金属板１が１枚ずつ吸盤２で吸引されて持ち上
げられ、そのラインに供給される。そのとき、図６に一
点鎖線で示すように、２枚の金属板が互いに吸着したま
ま吸盤２で持ち上げられてそのままラインに供給される
と、その金属板を加工する加工金型に多大な負荷がかか
り、その加工金型が破損する恐れがあり、これを避ける
ため、金属板１が２枚持ち上げられたことを検出し、２
枚持ち上げられた場合は、その金属板はラインに供給せ
ずに横に外しておく等の措置が必要となる。2. Description of the Related Art Conventionally, the discriminating apparatus as described above has been used in a wide variety of fields. Here, as an example thereof, an example of a device for detecting the overlapping of two metal plates will be described.
FIG. 6 is a schematic diagram showing an example of a two-metal-plate overlapping detection device. For example, on the most upstream side of a line for bending or punching a metal plate, a large number of stacked metal plates 1 are sucked up one by one with a suction cup 2 and then fed to the line. It At that time, as shown by the one-dot chain line in FIG. 6, when the two metal plates are sucked up from each other and lifted up by the suction cup 2 and supplied to the line as they are, a large load is applied to the processing die for processing the metal plates. There is a risk of damage to the processing die, and in order to avoid this, it is detected that two metal plates 1 have been lifted, and
When the sheets are lifted, it is necessary to take measures such as removing the metal plate sideways without supplying it to the line.
【０００３】そこで、ここには、金属板が２枚持ち上げ
られたことを検出する金属板２枚重ね検出装置３が備え
られている。この金属板２枚重ね検出装置３には、送信
ヘッド３１が備えられている。この送信ヘッド３１には
駆動コイル（図示せず）が備えられており、その駆動コ
イルはコイル駆動回路３２により駆動され交番磁界を発
生させる。このコイル駆動回路３２は、自動もしくは手
動切換えにより種々の周波数の駆動信号で駆動コイルを
駆動することができる。Therefore, here, there is provided a two-metal-plate overlapping detection device 3 for detecting that two metal plates have been lifted. This two-metal-plate stacking detection device 3 is provided with a transmission head 31. The transmission head 31 is provided with a drive coil (not shown), and the drive coil is driven by the coil drive circuit 32 to generate an alternating magnetic field. The coil drive circuit 32 can drive the drive coil with drive signals of various frequencies by automatic or manual switching.
【０００４】またこの金属板２枚重ね検出装置３には、
送信ヘッド３１と対向して受信ヘッド３３が備えられて
いる。この受信ヘッド３３には検出コイル（図示せず）
が備えられており、その検出コイルにより、送信ヘッド
３１で発せられ金属板１を透過した交番磁束が検出され
る。受信ヘッド３３中の検出コイルで検出された磁束
は、増幅回路３４で適切に増幅され整流回路３５でその
実効値が求められた後、比較回路３６に入力される。比
較回路３６には、しきい値生成回路３７で生成されたし
きい値も入力され、受信ヘッド３３で検出された磁束が
所定の強度以上であるか否か、即ち、金属板１を１枚だ
け通過したときの強度を有する磁束であるか、金属板１
を２枚（ないしそれ以上）通過したときの強度を有する
磁束であるかが判定され、これにより吸盤２で金属板１
が１枚だけ持ち上げられたかもしくは２枚以上持ち上げ
られたかが判別される。この判別結果を吸盤２を備えた
金属板供給装置に入力して吸盤２の動きを制御し、吸盤
２が金属板１を１枚だけ持ち上げた場合のみその金属板
１をラインに供給するように制御することにより、２枚
重ねの金属板の、ラインへの供給を避けることができ
る。Further, the two-metal-plate stacking detection device 3 includes
A reception head 33 is provided opposite to the transmission head 31. The receiving head 33 has a detection coil (not shown).
Is provided, and the alternating magnetic flux emitted from the transmission head 31 and transmitted through the metal plate 1 is detected by the detection coil. The magnetic flux detected by the detection coil in the reception head 33 is appropriately amplified by the amplification circuit 34, the effective value thereof is obtained by the rectification circuit 35, and then input to the comparison circuit 36. The threshold value generated by the threshold value generation circuit 37 is also input to the comparison circuit 36, and whether or not the magnetic flux detected by the reception head 33 is equal to or higher than a predetermined strength, that is, one metal plate 1 is used. Is the magnetic flux that has the strength when passing through the metal plate 1
It is determined whether or not the magnetic flux has the strength when passing two (or more) through the metal plate 1.
It is discriminated whether only one sheet has been lifted or two sheets or more have been lifted. This determination result is input to a metal plate supply device equipped with a suction cup 2 to control the movement of the suction cup 2 so that the metal plate 1 is supplied to the line only when the suction cup 2 lifts only one metal plate 1. By controlling, it is possible to avoid the supply of the double metal plate to the line.
【０００５】[0005]
【発明が解決しようとする課題】上記のような２枚重ね
検出装置は、受信ヘッド３３で受信される信号のレベル
の変化によって２枚重ねを検出するものであるが、検出
しようとする金属板の材質や厚さにより受信ヘッド３３
で受信される信号のレベルが極めて大きく変化する。例
えば鉄板等磁性の金属板については、減衰が大きく、し
たがって、これを調整するため交番磁界の周波数を下げ
ることにより減衰の程度を下げ、一方アルミニウム板等
非磁性の金属板については減衰が小さく、したがってこ
れを調整するため交番磁界の周波数を上げできるだけ減
衰させようとする。The above-mentioned double-sheet overlapping detecting device detects double-sheet overlapping by the change in the level of the signal received by the receiving head 33. The metal plate to be detected is to be detected. Depending on the material and thickness of the receiving head 33
The level of the signal received at changes extremely. For example, a magnetic metal plate such as an iron plate has a large attenuation, and therefore, the frequency of the alternating magnetic field is adjusted to adjust it to reduce the degree of the attenuation, while a non-magnetic metal plate such as an aluminum plate has a small attenuation. Therefore, in order to adjust this, the frequency of the alternating magnetic field is increased to try to attenuate it as much as possible.
【０００６】しかしながら、その調整のスパンが極めて
広く、例えば磁性の金属板を中心に回路定数等を定める
と、交番磁界の周波数を最大限に調整しても、非磁性の
厚さの薄い金属板の場合、金属板１枚であっても２枚重
なった場合であっても、その金属板を通過することによ
る交番磁束の減衰は極めて小さく十分なＳ／Ｎをもって
検出できないという問題がある。However, the span of the adjustment is extremely wide. For example, if the circuit constant and the like are determined centering on a magnetic metal plate, even if the frequency of the alternating magnetic field is adjusted to the maximum, the nonmagnetic thin metal plate is used. In such a case, there is a problem that, even if one metal plate or two metal plates are overlapped, the attenuation of the alternating magnetic flux due to passing through the metal plate is extremely small and cannot be detected with a sufficient S / N.
【０００７】本発明は上記事情に鑑み、特に非磁性の金
属板の厚さを高精度に弁別することのできる厚さ弁別装
置を提供することを目的とする。In view of the above circumstances, it is an object of the present invention to provide a thickness discriminating apparatus capable of discriminating the thickness of a non-magnetic metal plate with high accuracy.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成する本発
明の厚さ弁別装置は、交番磁束を発生する送信ヘッド
と、該送信ヘッドから発せられ被検査体を透過した交番
磁束を検出する受信ヘッドと、被検査体透過前後の交番
磁束の位相ずれに基づいて、被検査体の厚さを複数に弁
別する弁別回路とを備えたことを特徴とするものであ
る。SUMMARY OF THE INVENTION A thickness discriminating apparatus of the present invention which achieves the above object comprises a transmitting head for generating an alternating magnetic flux, and a receiving head for detecting an alternating magnetic flux emitted from the transmitting head and transmitted through an object to be inspected. It is characterized by comprising a head and a discriminating circuit for discriminating the thickness of the inspection object into a plurality of pieces based on the phase shift of the alternating magnetic flux before and after the inspection object is transmitted.
【０００９】ここで、上記弁別回路が、被検査体透過前
後の交番磁束の位相ずれとともに被検査体を透過したこ
とによる交番磁束の減衰のレベルに基づいて、被検査体
の厚さを複数に弁別するものであることが好ましい。上
記弁別回路は、具体的には、被検査体透過前の交番磁束
に対応する信号を参照信号として、被検査体透過後の交
番磁束に対応する信号を位相検波する位相検波回路と、
位相検波後の信号を整流する整流回路と、該整流回路の
出力と所定のしきい値とを比較する比較回路とを備えた
構成とすることができる。Here, the discriminating circuit has a plurality of thicknesses of the object to be inspected on the basis of the phase shift of the alternating magnetic flux before and after passing through the object to be inspected and the attenuation level of the alternating magnetic flux due to transmission through the object to be inspected. It is preferable to discriminate. The discrimination circuit, specifically, a signal corresponding to the alternating magnetic flux before the inspection object transmission as a reference signal, a phase detection circuit for phase-detecting the signal corresponding to the alternating magnetic flux after the inspection object transmission,
The configuration may include a rectifier circuit that rectifies the signal after the phase detection and a comparison circuit that compares the output of the rectifier circuit with a predetermined threshold value.
【００１０】[0010]
【作用】本発明者らの観察によると、磁性の金属板を通
過した後の交番磁束と非磁性の金属板を通過した後の交
番磁束とでは減衰率の相違のほか、磁性の金属板では通
過前後の交番磁束の位相が僅かしか変化しておらず、一
方、非磁性の金属板では通過前後の交番磁束の位相がそ
の金属板の厚さに応じ大きく変化する。その原因は正確
には不明であるが、例えば以下の原因が考えられる。According to the observation of the present inventors, in addition to the difference in the attenuation rate between the alternating magnetic flux after passing through the magnetic metal plate and the alternating magnetic flux after passing through the non-magnetic metal plate, in the magnetic metal plate The phase of the alternating magnetic flux before and after passing changes only slightly, while in the non-magnetic metal plate, the phase of the alternating magnetic flux before and after passing greatly changes according to the thickness of the metal plate. Although the exact cause is unknown, the following causes are considered, for example.
【００１１】非磁性金属での磁束の減衰は主としてうず
損Ｗｅによるものであり、磁性金属の場合はうず損Ｗｅ
とヒステリシス損Ｗｈとの和として表わされる。すなわ
ち、交番磁束のキャリア周波数をｆとすると、各々の損
失は、下記（１）式，（２）式として表現することがで
きる。 非磁性金属による損失ＷNM＝Ｗｅ・ｆ2 …（１） 磁性金属による損失ＷM ＝Ｗｅ・ｆ2 ＋Ｗh ・ｆ …（２） うず損の時は位相後れが生じ、ヒステリシス損が生じる
時は、ヒステリシス進相角により位相が進む。このこと
から、非磁性金属の場合はうず損による大きな位相遅れ
が観察され、磁性金属の場合はうず損による位相遅れと
ヒステリシス損による位相進みが相殺し合って位相変化
は僅かしか観察されないものと考えられる。The attenuation of the magnetic flux in the non-magnetic metal is mainly due to the eddy loss We, and in the case of the magnetic metal, the eddy loss We.
And hysteresis loss Wh. That is, assuming that the carrier frequency of the alternating magnetic flux is f, each loss can be expressed by the following equations (1) and (2). Loss due to non-magnetic metal W NM = We · f 2 (1) Loss due to magnetic metal W M = We · f 2 + W h · f (2) Phase shift occurs when eddy loss occurs and hysteresis loss occurs At time, the phase advances due to the hysteresis advance angle. From this, a large phase delay due to eddy loss is observed in the case of non-magnetic metal, and a phase change due to eddy loss and a phase lead due to hysteresis loss cancel each other out in the case of magnetic metal, and only a slight phase change is observed. Conceivable.
【００１２】本発明は、上記観察結果に鑑みなされたも
のであり、本発明の厚さ弁別装置は非検査体透過前後の
交番磁界の位相ずれに基づいて被検査体の厚さを複数に
弁別する弁別回路を備えたため、特に非磁性の金属板等
厚さに応じて交番磁界の位相が変化する被検査体の場合
に高精度の厚さ弁別が可能となる。また、本発明の厚さ
弁別装置において、交番磁界の位相ずれと共に、従来同
様、その交番磁界の減衰のレベルに基づいて被検査体の
厚さを複数に弁別する弁別回路を備えると、非磁性、磁
性を問わず広範な被検査体の厚さを高精度に弁別するこ
とができる。The present invention has been made in view of the above observation results, and the thickness discriminating apparatus of the present invention discriminates a plurality of thicknesses of an object to be inspected on the basis of the phase shift of the alternating magnetic field before and after passing through the non-inspection object. Since the discriminating circuit is provided, highly accurate thickness discrimination can be performed especially in the case of an object to be inspected in which the phase of the alternating magnetic field changes depending on the thickness of a non-magnetic metal plate or the like. Further, in the thickness discriminating apparatus of the present invention, when a discriminating circuit for discriminating the thickness of the object to be inspected into a plurality of pieces based on the level of attenuation of the alternating magnetic field is provided as well as the phase shift of the alternating magnetic field, the non-magnetic Therefore, it is possible to accurately discriminate a wide range of thicknesses of the inspection object regardless of magnetism.
【００１３】[0013]
【実施例】以下、本発明の実施例について説明する。図
１は、本発明の厚さ弁別回路の一実施例を表わす金属板
２枚重ね検出装置のブロック図である。図６に示す従来
例の各ブロックに対応するブロックには、図６に付した
番号と同一の番号を付して示し、相違点について説明す
る。Embodiments of the present invention will be described below. FIG. 1 is a block diagram of a two-metal-plate superposition detecting device showing an embodiment of a thickness discriminating circuit of the present invention. The blocks corresponding to the blocks of the conventional example shown in FIG. 6 are denoted by the same numbers as the numbers given in FIG. 6, and the differences will be described.
【００１４】図１に示す厚さ弁別回路４には、位相検波
回路４１が備えられている。この位相検波回路４１で
は、送信ヘッド３１に備えられた駆動コイルを駆動する
ための、コイル駆動回路３２から出力された駆動信号を
参照信号Ｓｒｅｆとして、受信ヘッド３３に備えられた
検出コイルで検出された信号Ｓｐｉｃｋが位相検波され
る。位相検波された信号Ｓｄｅｔは、整流回路３５に入
力され整流されることによりその実効値が求められ、比
較回路３６で２枚重ねか否かが検出される。The thickness discriminating circuit 4 shown in FIG. 1 is provided with a phase detecting circuit 41. In the phase detection circuit 41, the drive signal output from the coil drive circuit 32 for driving the drive coil provided in the transmission head 31 is detected by the detection coil provided in the reception head 33 as the reference signal Sref. The signal Spick is phase-detected. The phase-detected signal Sdet is input to the rectifier circuit 35 and rectified to obtain the effective value thereof, and the comparison circuit 36 detects whether or not two sheets are stacked.
【００１５】図２は、参照信号（Ａ）、磁性金属板の一
例としての鉄板１枚のときの検出信号（Ｂ）、および鉄
板２枚のときの検出信号（Ｃ）をタイミングを合わせて
示した図である。鉄板１枚のときの検出信号（Ｂ）と２
枚のときの検出信号（Ｃ）を比較すると位相の変化はほ
とんどあるいは僅かしか見られないが、その振幅が大き
く変化しており、交番磁束が鉄板を通過する間に大きく
減衰することがわかる。FIG. 2 shows the reference signal (A), the detection signal (B) when one iron plate is used as an example of a magnetic metal plate, and the detection signal (C) when two iron plates are used at the same timing. It is a figure. Detection signal (B) and 2 when one iron plate is used
Comparing the detection signals (C) when the number of sheets is one, little or little change in the phase is observed, but the amplitude is greatly changed, and it can be seen that the alternating magnetic flux is greatly attenuated while passing through the iron plate.
【００１６】図３は、参照信号（Ａ）、および鉄板１枚
および２枚のときの位相検波後の信号（Ｂ），（Ｃ）を
示した図である。鉄板の場合、厚さ（枚数）に応じて検
出信号Ｓｐｉｃｋの振幅が大きく変化するため、位相検
波後の信号Ｓｄｅｔもその枚数に応じてレベルが大きく
変化し、このレベル変化に基づいて鉄板１枚と２枚重ね
とを十分な高精度で弁別することができる。FIG. 3 is a diagram showing a reference signal (A) and signals (B) and (C) after phase detection for one and two iron plates. In the case of an iron plate, the amplitude of the detection signal Spick greatly changes according to the thickness (number of sheets), so that the level of the signal Sdet after phase detection also greatly changes according to the number of iron plates. Can be discriminated from each other with a sufficiently high accuracy.
【００１７】図４は、参照信号（Ａ）、非磁性金属板の
一例としてのアルミニウム板１枚のときの検出信号
（Ｂ）、およびアルミニウム板２枚のときの検出信号
（Ｃ）をタイミングを合わせて示した図である。アルミ
ニウム板の場合、１枚の場合（Ｂ）と２枚の場合（Ｃ）
とを比べ、その振幅の変化は小さい。ただし、アルミニ
ウム板の場合、厚さ（枚数）に応じて検出信号Ｓｐｉｃ
ｋの位相が大きく変化している。FIG. 4 shows the timing of the reference signal (A), the detection signal (B) when one aluminum plate is used as an example of the non-magnetic metal plate, and the detection signal (C) when two aluminum plates are used. It is the figure shown together. In the case of aluminum plate, one sheet (B) and two sheets (C)
Compared with, the change in the amplitude is small. However, in the case of an aluminum plate, the detection signal Spic depends on the thickness (number of sheets).
The phase of k has changed significantly.
【００１８】図５は、参照信号（Ａ）、およびアルミニ
ウム板１枚および２枚のときの位相検波後の信号
（Ｂ），（Ｃ）を示した図である。この図５（Ｂ），
（Ｃ）では、位相検波後の信号Ｓｄｅｔとして、飽和レ
ベルにまで増幅した矩形信号（実線）と飽和していない
位相検波信号（一点鎖線）との双方が示されている。FIG. 5 is a diagram showing a reference signal (A) and signals (B) and (C) after phase detection for one and two aluminum plates. This FIG. 5 (B),
In (C), as the signal Sdet after phase detection, both a rectangular signal amplified to a saturation level (solid line) and a phase detection signal not saturated (dashed line) are shown.
【００１９】アルミニウム板（非磁性金属板）の場合、
鉄板（磁性金属板）と比べ交番磁束の減衰率が極めて小
さく、したがって位相検波回路４１における増幅率を大
きく変化させず図５（Ｂ），（Ｃ）に実線で示すような
矩形信号が出力されるようにその増幅率を設定すること
もできる。図５（Ｂ），（Ｃ）に示すように、アルミニ
ウム板の場合、厚さ（枚数）に応じて位相が大きく変化
するため、飽和させた矩形信号を整流することによりそ
の位相に応じたレベルの直流信号が得られ、あるいは飽
和させずに位相と振幅との双方に応じたレベルの直流信
号が得られ、アルミニウム板が１枚のみであるか２枚重
なっているかを高精度に弁別することができる。In the case of an aluminum plate (non-magnetic metal plate),
The attenuation factor of the alternating magnetic flux is extremely smaller than that of the iron plate (magnetic metal plate). Therefore, the rectangular signal as shown by the solid line in FIGS. 5B and 5C is output without greatly changing the amplification factor in the phase detection circuit 41. The amplification factor can be set so that As shown in FIGS. 5 (B) and 5 (C), in the case of an aluminum plate, the phase greatly changes depending on the thickness (number of sheets). Therefore, by rectifying the saturated rectangular signal, the level corresponding to the phase is changed. DC signal is obtained, or a DC signal with a level corresponding to both phase and amplitude is obtained without saturating, and it is possible to accurately discriminate whether there is only one aluminum plate or two aluminum plates are overlapped. You can
【００２０】尚、上記実施例は位相変化を捉えた高精度
な弁別を行なうために位相検波回路を備えたが、本発明
は、位相変化に基づいて被検査体の厚さを複数に弁別で
きればよく、必ずしも位相検波を行なう方式に限定され
るものではない。また、上記実施例は金属板の２枚重ね
を検出する例であるが、本発明の厚さ弁別装置の用途は
金属板の２枚重ねの検出にのみ適用されるものではな
く、被検査体の厚さを複数に弁別する場合一般に広く適
用することができる。Although the above embodiment is provided with the phase detection circuit for performing the highly accurate discrimination by detecting the phase change, the present invention is capable of discriminating the thickness of the object to be inspected into a plurality of thicknesses based on the phase change. However, the method is not necessarily limited to the method of performing the phase detection. Further, although the above-mentioned embodiment is an example of detecting the double stacking of the metal plates, the application of the thickness discriminating apparatus of the present invention is not applied only to the detection of the double stacking of the metal plates, but the object to be inspected. In the case of discriminating a plurality of thicknesses, it is generally applicable widely.
【００２１】[0021]
【発明の効果】以上説明したように、本発明の弁別装置
によれば、被検査体透過前後の交番磁束の位相ずれに基
づいて、被検査体の厚さを複数に弁別するものであるた
め、非磁性の金属板等を被検査体とする場合に高精度な
厚さ弁別を行なうことができる。また、本発明の厚さ弁
別装置において、被検査体透過前後の交番磁束の位相ず
れとともに被検査体を透過したことによる交番磁束の減
衰のレベルに基づいて、被検査体の厚さを複数に弁別す
る構成を備えた場合、非磁性、磁性を問わず広範な被検
査体の厚さを高精度に弁別することができる。As described above, according to the discriminating apparatus of the present invention, the thickness of the object to be inspected is discriminated into a plurality of thicknesses based on the phase shift of the alternating magnetic flux before and after passing through the object to be inspected. In the case where a non-magnetic metal plate or the like is used as the inspection object, highly accurate thickness discrimination can be performed. Further, in the thickness discriminating apparatus of the present invention, based on the phase shift of the alternating magnetic flux before and after passing through the inspected object and the level of attenuation of the alternating magnetic flux due to transmission through the inspected object, the thickness of the inspected object is made plural. When the structure for discriminating is provided, it is possible to discriminate a wide range of thicknesses of the object to be inspected with high accuracy regardless of whether it is magnetic or non-magnetic.
【図１】本発明の厚さ弁別回路の一実施例を表わす金属
板２枚重ね検出装置のブロック図である。FIG. 1 is a block diagram of a two-metal-plate overlapping detection apparatus that represents an embodiment of a thickness discrimination circuit of the present invention.
【図２】参照信号（Ａ）、磁性金属板の一例としての鉄
板１枚のときの検出信号（Ｂ）、および鉄板２枚のとき
の検出信号（Ｃ）をタイミングを合わせて示した図であ
る。FIG. 2 is a diagram showing timings of a reference signal (A), a detection signal (B) when one iron plate is an example of a magnetic metal plate, and a detection signal (C) when two iron plates are used. is there.
【図３】参照信号（Ａ）、および鉄板１枚および２枚の
ときの位相検波後の信号（Ｂ），（Ｃ）を示した図であ
る。FIG. 3 is a diagram showing a reference signal (A) and signals (B) and (C) after phase detection for one and two iron plates.
【図４】参照信号（Ａ）、非磁性金属板の一例としての
アルミニウム板１枚のときの検出信号（Ｂ）、およびア
ルミニウム板２枚のときの検出信号（Ｃ）をタイミング
を合わせて示した図である。FIG. 4 shows a reference signal (A), a detection signal (B) in the case of one aluminum plate as an example of a non-magnetic metal plate, and a detection signal (C) in the case of two aluminum plates at the same timing. It is a figure.
【図５】参照信号（Ａ）、およびアルミニウム板１枚お
よび２枚のときの位相検波後の信号（Ｂ），（Ｃ）を示
した図である。FIG. 5 is a diagram showing a reference signal (A) and signals (B) and (C) after phase detection with one and two aluminum plates.
【図６】従来の金属板２枚重ね検出装置を示す模式図で
ある。FIG. 6 is a schematic diagram showing a conventional two-metal-plate stacking detection device.
４ 厚さ弁別回路 ３１ 送信ヘッド ３２ コイル駆動回路 ３３ 受信ヘッド ３５ 整流回路 ３６ 比較回路 ３７ しきい値生成回路 ４１ 位相検波回路 4 Thickness Discrimination Circuit 31 Transmission Head 32 Coil Drive Circuit 33 Reception Head 35 Rectifier Circuit 36 Comparison Circuit 37 Threshold Generation Circuit 41 Phase Detection Circuit
Claims (3)
を検出する受信ヘッドと、 被検査体透過前後の交番磁束の位相ずれに基づいて、被
検査体の厚さを複数に弁別する弁別回路とを備えたこと
を特徴とする厚さ弁別装置。1. A transmission head that generates an alternating magnetic flux, a reception head that detects the alternating magnetic flux emitted from the transmission head and transmitted through an object to be inspected, and a phase shift of the alternating magnetic flux before and after transmission through the object to be inspected. A thickness discriminating apparatus comprising: a discriminating circuit for discriminating a plurality of thicknesses of an object to be inspected.
番磁束の位相ずれとともに被検査体を透過したことによ
る交番磁束の減衰のレベルに基づいて、被検査体の厚さ
を複数に弁別するものであることを特徴とする請求項１
記載の厚さ弁別装置。2. The discriminating circuit discriminates a plurality of thicknesses of the object to be inspected on the basis of the phase shift of the alternating magnetic flux before and after passing through the object to be inspected and the attenuation level of the alternating magnetic flux transmitted through the object to be inspected. The method according to claim 1, wherein
The described thickness discriminating device.
して、被検査体透過後の交番磁束に対応する信号を位相
検波する位相検波回路と、 位相検波後の信号を整流する整流回路と、 該整流回路の出力と所定のしきい値とを比較する比較回
路とを備えたことを特徴とする請求項１又は２記載の厚
さ弁別装置。3. A phase detection circuit, wherein the discrimination circuit phase-detects a signal corresponding to the alternating magnetic flux after passing through the inspected body using a signal corresponding to the alternating magnetic flux before passing through the inspected body as a reference signal. 3. The thickness discriminating device according to claim 1, further comprising a rectifying circuit for rectifying a subsequent signal and a comparing circuit for comparing an output of the rectifying circuit with a predetermined threshold value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29500694A JP3519806B2 (en) | 1994-11-29 | 1994-11-29 | Thickness discriminator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29500694A JP3519806B2 (en) | 1994-11-29 | 1994-11-29 | Thickness discriminator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08152302A true JPH08152302A (en) | 1996-06-11 |
| JP3519806B2 JP3519806B2 (en) | 2004-04-19 |
Family
ID=17815123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29500694A Expired - Fee Related JP3519806B2 (en) | 1994-11-29 | 1994-11-29 | Thickness discriminator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3519806B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008111738A (en) * | 2006-10-31 | 2008-05-15 | Railway Technical Res Inst | Thickness measuring device and thickness measuring program |
| CN100449254C (en) * | 2005-12-27 | 2009-01-07 | 林俊明 | An electromagnetic detection method for the thickness of non-metallic materials |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4943217B1 (en) * | 1969-10-27 | 1974-11-20 | ||
| JPS55159102A (en) * | 1979-05-31 | 1980-12-11 | Nippon Densokuki Kenkyusho:Kk | Thickness measuring method of nonmagnetic metal sheet |
| JPS56112602A (en) * | 1980-02-13 | 1981-09-05 | Nippon Densokuki Kenkyusho:Kk | Measuring device for thickness of nonmagnetic thin metal plate |
| JPS59114247A (en) * | 1982-12-17 | 1984-07-02 | Riide Denki Kk | Double sheet feed detector |
| JPS6166104A (en) * | 1984-09-07 | 1986-04-04 | Anelva Corp | Method for measuring thickness of thin metal film |
| JPH03272491A (en) * | 1990-03-22 | 1991-12-04 | Nippon Seimitsu Denki Kk | Detector of overlapping of thin plates |
-
1994
- 1994-11-29 JP JP29500694A patent/JP3519806B2/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4943217B1 (en) * | 1969-10-27 | 1974-11-20 | ||
| JPS55159102A (en) * | 1979-05-31 | 1980-12-11 | Nippon Densokuki Kenkyusho:Kk | Thickness measuring method of nonmagnetic metal sheet |
| JPS56112602A (en) * | 1980-02-13 | 1981-09-05 | Nippon Densokuki Kenkyusho:Kk | Measuring device for thickness of nonmagnetic thin metal plate |
| JPS59114247A (en) * | 1982-12-17 | 1984-07-02 | Riide Denki Kk | Double sheet feed detector |
| JPS6166104A (en) * | 1984-09-07 | 1986-04-04 | Anelva Corp | Method for measuring thickness of thin metal film |
| JPH03272491A (en) * | 1990-03-22 | 1991-12-04 | Nippon Seimitsu Denki Kk | Detector of overlapping of thin plates |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100449254C (en) * | 2005-12-27 | 2009-01-07 | 林俊明 | An electromagnetic detection method for the thickness of non-metallic materials |
| JP2008111738A (en) * | 2006-10-31 | 2008-05-15 | Railway Technical Res Inst | Thickness measuring device and thickness measuring program |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3519806B2 (en) | 2004-04-19 |
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