JPH08145815A - Stress sensor - Google Patents
Stress sensorInfo
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- JPH08145815A JPH08145815A JP28935894A JP28935894A JPH08145815A JP H08145815 A JPH08145815 A JP H08145815A JP 28935894 A JP28935894 A JP 28935894A JP 28935894 A JP28935894 A JP 28935894A JP H08145815 A JPH08145815 A JP H08145815A
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- Prior art keywords
- stress
- measured
- layer
- magnetic
- stress sensor
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- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は被測定物に負荷されてい
る応力を磁気的な手法を用いて、その場で非破壊的に検
出するために被測定物に貼り付けて使用する応力センサ
ーに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stress sensor which is attached to an object to be measured in order to non-destructively detect the stress applied to the object to be measured on the spot using a magnetic method. Regarding
【０００２】[0002]
【従来の技術】建築物，鉄道レール，橋梁等を構成する
構造材料には、風力や温度の変化や自重等により局所的
に圧縮や引っ張りの応力が発生する。この応力が限界値
を超えると、構造材料の破損や湾曲が発生し、建築物の
倒壊や列車の脱線等の人命に関わる災害につながる場合
が多い。このために、自然環境から受ける変化を考慮し
た構造設計及び施工が行われているが、これらに加え
て、構造材料に発生している応力を測定し、それを管理
することによって安全性を確保する試みが行われ、一部
においては実用化している。2. Description of the Related Art Structural materials constituting buildings, railway rails, bridges, etc. are locally subjected to compressive and tensile stresses due to changes in wind force, temperature, self-weight and the like. When the stress exceeds the limit value, structural materials are damaged or curved, which often leads to human-life-related disasters such as collapse of buildings and derailment of trains. For this reason, structural design and construction are carried out in consideration of changes caused by the natural environment, but in addition to these, the stress generated in the structural material is measured and the safety is secured by managing it. Attempts have been made to do so, and some have put it to practical use.
【０００３】従来から、構造材料に負荷される応力を磁
気的な方法によって測定する技術開発が行われている。
磁気的な方法とは、例えば励磁ヘッドと検出ヘッドから
なる磁気ヘッドを用いて被測定物の磁気的性質を反映し
た磁気信号を検出し、特に応力の負荷で生ずる磁気信号
の変化を捉えることにより、被測定物に負荷される応力
を測定するものである。磁気的な手法では、非接触で測
定を行うことも可能であるので、オンライン測定への拡
張も期待できる。Conventionally, technical developments have been made to measure the stress applied to structural materials by a magnetic method.
The magnetic method is, for example, to detect a magnetic signal that reflects the magnetic properties of the object to be measured using a magnetic head composed of an excitation head and a detection head, and particularly to grasp the change of the magnetic signal caused by the stress load. The stress applied to the object to be measured is measured. Since it is also possible to perform non-contact measurement by the magnetic method, it can be expected to be extended to online measurement.
【０００４】例えば、応力測定のために提案されている
具体的な公知例としては、被測定物の保磁力が応力によ
って変化することを利用した特公昭５２−１４９８６号
公報に記載の非接触式応力測定装置があげられる。ま
た、クロスセンサを用いた被測定物の磁気異方性の分
布，変化の測定方法として、特公昭６１−３１８２８号
公報に記載の磁気異方性パターンの測定方法が提案され
ている。最近では被測定物の磁化の不連続性に起因する
バルクハウゼン信号を用いた応力測定法が注目されてい
る。For example, as a specific publicly known example proposed for stress measurement, a non-contact method disclosed in Japanese Patent Publication No. 52-14986, which utilizes the fact that the coercive force of an object to be measured changes with stress. A stress measuring device can be used. Further, as a method of measuring the distribution and change of magnetic anisotropy of an object to be measured using a cross sensor, a method of measuring a magnetic anisotropy pattern described in Japanese Patent Publication No. 61-31828 is proposed. Recently, a stress measurement method using a Barkhausen signal due to the discontinuity of the magnetization of an object to be measured has attracted attention.
【０００５】ここで構造物に負荷される応力を磁気的に
測定する場合、構造物に励磁にともない磁気信号を発生
する応力センサー板を付与させ、磁気信号の応力依存性
から応力を判定する技術が公知になっている。具体的に
は米国特許第３，４２７，８７２号明細書において、被
測定物が非磁性体の場合には測定物表面に強磁性体の板
を貼り付けて、そこから発生するバルクハウゼン信号よ
り測定物に負荷される応力を測定する方法が示されてい
る。また、特開昭６１−２５８１６１号公報に記載の無
接触磁気応力および温度検知器では、二種類の強磁性体
層を重ねて非強磁性物体表面に接着し、それぞれの層か
ら発生する大バルクハウゼンノイズの発生時間の差から
応力や温度を測定する検知器が提案されている。さら
に、本発明者は特願平６−７０３６６号にて、炭素鋼材
からなり、発生するバルクハウゼン信号が測定温度に影
響されない応力センサーを示している。In the case of magnetically measuring the stress applied to a structure, a stress sensor plate for generating a magnetic signal upon excitation is attached to the structure and the stress is determined from the stress dependence of the magnetic signal. Is publicly known. Specifically, in U.S. Pat. No. 3,427,872, when the object to be measured is a non-magnetic material, a plate of a ferromagnetic material is attached to the surface of the object to be measured, and a Barkhausen signal generated from the plate is used. A method for measuring the stress applied to a measurement object is shown. Further, in the contactless magnetic stress and temperature detector described in JP-A-61-258161, two types of ferromagnetic layers are superposed and adhered to the surface of a non-ferromagnetic object to form a large bulk. A detector has been proposed that measures stress and temperature from the difference in the generation time of Hausen noise. Further, the present inventor discloses in Japanese Patent Application No. 6-70366 a stress sensor made of a carbon steel material, in which the generated Barkhausen signal is not affected by the measurement temperature.
【０００６】さて、磁気的な方法を用いて高い精度の応
力測定を行うためには、応力以外の外乱要素を除去する
ことが重要である。最も除去が難しく、測定精度に影響
を及ぼす要素として、被測定物に流れる電流や磁束が挙
げられる。In order to perform highly accurate stress measurement using a magnetic method, it is important to remove disturbance elements other than stress. The factors that are the most difficult to remove and that affect the measurement accuracy include the current and magnetic flux flowing through the object to be measured.
【０００７】構造物に電流が流れたり、磁束が通ってい
たりする場合には、磁気的な手法を用いた応力測定には
大きな影響が生じる。例えば、鉄道レールの場合には、
レールの長手方向へ信号電流や電車モーター電流が流
れ、この電流によりレールが磁化し、また磁束がレール
表面付近に漏洩する。これらの電流値は随時変化するの
で、それに伴いレールの磁化量や漏洩磁束量が変化す
る。その様な状況の中で、磁気的な手法を用いて応力を
測定する場合には、得られる磁気信号はレールに流れる
電流値により変動するので、従来技術ではレールに負荷
される応力を正確に測定することはできない。When an electric current flows or a magnetic flux passes through the structure, the stress measurement using the magnetic method has a great influence. For example, in the case of railroad rails,
A signal current and a train motor current flow in the longitudinal direction of the rail, the current magnetizes the rail, and magnetic flux leaks near the rail surface. Since these current values change from time to time, the amount of magnetization of the rail and the amount of magnetic flux leakage change accordingly. In such a situation, when measuring the stress using a magnetic method, the obtained magnetic signal fluctuates depending on the current value flowing in the rail. It cannot be measured.
【０００８】現在のところ、被測定物に流れる電流や磁
束の影響を除去する方法がないために、応力測定が必要
とされる場合でも、上記の理由で磁気的な方法が適用で
きないケースが多数存在する。At present, there is no method for removing the influence of the current or magnetic flux flowing through the object to be measured, and even when stress measurement is required, there are many cases where the magnetic method cannot be applied for the above reason. Exists.
【０００９】[0009]
【発明が解決しようとする課題】上述したように、電流
や磁束が流れる被測定物に対して、磁気的な方法で応力
を測定しようとする場合、従来では被測定物からの漏れ
磁束や漏れ電流の影響により精度が著しく低下する。As described above, when the stress is to be measured by a magnetic method with respect to an object to be measured in which an electric current or magnetic flux flows, conventionally, leakage flux or leakage from the object to be measured is used. Accuracy is significantly reduced due to the influence of current.
【００１０】本発明は、電流や磁束が流れる被測定物に
対しても、応力を磁気的な手法を用いて精度良く測定可
能とすることを課題としている。An object of the present invention is to make it possible to measure the stress with high accuracy using a magnetic method even for an object to be measured in which a current or magnetic flux flows.
【００１１】[0011]
【課題を解決するための手段】本発明の要旨とするとこ
ろは、下記の通りである： １．応力測定を行うために被測定物に貼り付けて使用
し、発生する磁気信号により応力を測定可能とする応力
センサーであって、被測定物に貼り付ける面から数えた
第一層目が非磁性材料からなり、第二層目が強磁性材料
からなる二層構造を特徴とする応力センサー； ２．第一層目の非磁性材料の厚みが５μｍ以上２０ｍｍ
以下であり、第二層目の強磁性材料の厚みが０．１μｍ
以上１０ｍｍ以下であることを特徴とする前項１．に記
載の応力センサー； ３．応力測定を行うために被測定物に貼り付けて使用
し、発生する磁気信号により応力を測定可能とする応力
センサーであって、被測定物に貼り付ける面から数えた
第一層目が電気絶縁性材料からなり、第二層目が強磁性
材料からなる二層構造を特徴とする応力センサー； ４．第一層目の電気絶縁性材料の厚みが１μｍ以上５０
０μｍ以下であり、第二層目の強磁性材料の厚みが０．
１μｍ以上１０ｍｍ以下であることを特徴とする前項
３．に記載の応力センサー； ５．応力測定を行うために被測定物に貼り付けて使用
し、発生する磁気信号により応力を測定可能とする応力
センサーであって、被測定物に貼り付ける面から数えた
第三層目が強磁性材料からなり、他の二層が非磁性材料
および電気絶縁性材料からなる三層構造を特徴とする応
力センサー； ６．電気絶縁材料の厚みが１μｍ以上５００μｍ以下で
あり、非磁性材料の厚みが５μｍ以上２０ｍｍ以下であ
り、強磁性材料の厚みが０．１μｍ以上１０ｍｍ以下で
あることを特徴とする前項５．に記載の応力センサー； ７．応力測定を行うために被測定物に貼り付けて使用
し、発生する磁気信号により応力を測定可能とする応力
センサーであって、被測定物に貼り付ける面から数えた
第一層目が非磁性かつ電気絶縁性の材料からなり、第二
層目が強磁性材料からなる二層構造を特徴とする応力セ
ンサー； ８．非磁性かつ電気絶縁性の材料の厚みが５μｍ以上２
０ｍｍ以下であり、強磁性材料の厚みが０．１μｍ以上
１０ｍｍ以下であることを特徴とする前項７．に記載の
応力センサー。The gist of the present invention is as follows: It is a stress sensor that is used by sticking to the object to be measured to measure the stress, and it is possible to measure the stress by the generated magnetic signal.The first layer counted from the surface to be bonded to the object is non-magnetic. 1. a stress sensor characterized by a two-layer structure made of a material, the second layer of which is a ferromagnetic material; The thickness of the non-magnetic material in the first layer is 5 μm or more and 20 mm
And the thickness of the ferromagnetic material of the second layer is 0.1 μm
1. The above-mentioned item 1. 2. The stress sensor according to 1. It is a stress sensor that is used by pasting it on the object to be measured to measure the stress, and the stress can be measured by the generated magnetic signal.The first layer counted from the surface to be attached to the object is electrically insulating. 3. A stress sensor characterized by a two-layer structure made of a magnetic material and a second layer made of a ferromagnetic material; The thickness of the electrically insulating material of the first layer is 1 μm or more 50
The thickness of the ferromagnetic material of the second layer is 0.
2. It is 1 μm or more and 10 mm or less. 4. The stress sensor according to 5. It is a stress sensor that is used by sticking to the object to be measured to measure the stress, and it is possible to measure the stress by the generated magnetic signal.The third layer counted from the surface to be bonded to the object is ferromagnetic. 5. A stress sensor characterized by a three-layer structure consisting of a material, the other two layers of which are a non-magnetic material and an electrically insulating material; 4. The thickness of the electrically insulating material is 1 μm or more and 500 μm or less, the thickness of the non-magnetic material is 5 μm or more and 20 mm or less, and the thickness of the ferromagnetic material is 0.1 μm or more and 10 mm or less. 6. The stress sensor according to 7. It is a stress sensor that is used by sticking to the object to be measured to measure the stress, and it is possible to measure the stress by the generated magnetic signal.The first layer counted from the surface to be bonded to the object is non-magnetic. 7. A stress sensor characterized by a two-layer structure made of an electrically insulating material and a second layer made of a ferromagnetic material; The thickness of the non-magnetic and electrically insulating material is 5 μm or more 2
7. The thickness is 0 mm or less, and the thickness of the ferromagnetic material is 0.1 μm or more and 10 mm or less. The stress sensor described in.
【００１２】[0012]
【作用】本発明は、磁気的に応力を検出するために構造
物へ貼り付ける応力センサーに関するものである。該応
力センサーは応力を測定すべき構造物に貼り付けられ、
−３〜３０ｋｇ／ｍｍ2の測定ダイナミックレンジで応
力測定を可能とする。The present invention relates to a stress sensor attached to a structure for magnetically detecting stress. The stress sensor is attached to a structure whose stress is to be measured,
It enables stress measurement with a measurement dynamic range of -3 to 30 kg / mm 2 .
【００１３】貼り付けた応力センサーから磁気信号を得
るためには、例えば磁気ヘッドを用いる。磁気ヘッドは
励磁ヘッドと検出ヘッドから構成され、励磁ヘッドによ
り応力センサーを交流励磁し、検出ヘッドにより応力セ
ンサーから発生する磁気信号を検出する。応力測定に
は、磁気信号から求められる保磁力や透磁率等の磁気特
性や、検出される磁気信号のうち高周波成分であるバル
クハウゼン信号を用いることができる。A magnetic head, for example, is used to obtain a magnetic signal from the attached stress sensor. The magnetic head is composed of an exciting head and a detecting head. The exciting head AC excites the stress sensor, and the detecting head detects a magnetic signal generated from the stress sensor. For the stress measurement, magnetic properties such as coercive force and magnetic permeability obtained from the magnetic signal and Barkhausen signal which is a high frequency component of the detected magnetic signal can be used.
【００１４】該応力センサーの形状は板状もしくは被測
定物の表面形状に密着できる形状であれば良い。応力セ
ンサーの厚みに対し垂直で磁気信号を発生する表面の面
積は該センサー１枚当たり０．５ｍｍ2以上１００００
ｍｍ2以下が望ましい。面積が０．５ｍｍ2未満であると
検出できる磁気信号の強度が低く、測定精度が落ちる。
また１００００ｍｍ2を超えると、構造物の局所的な応
力分布を求めることができなくなる。構造と寸法につい
ては更に後述する。The shape of the stress sensor may be a plate shape or a shape capable of closely adhering to the surface shape of the object to be measured. The area of the surface that generates a magnetic signal perpendicular to the thickness of the stress sensor is 0.5 mm 2 or more and 10000 per sensor.
mm 2 or less is desirable. If the area is less than 0.5 mm 2 , the strength of the magnetic signal that can be detected is low, and the measurement accuracy is reduced.
If it exceeds 10000 mm 2 , it becomes impossible to obtain the local stress distribution of the structure. The structure and dimensions will be described further below.
【００１５】構造物への貼り付けは接着剤を用いる接
着、アーク放電等を用いる溶接によって行うことができ
る。ただし、溶接法では溶接部の組織が変わってしまう
ので、該応力センサーの大きさは信号を検出するために
使用する磁気ヘッドの検出領域の大きさよりも熱影響部
の大きさ分だけ大きくする必要がある。The attachment to the structure can be carried out by adhesion using an adhesive, welding by using arc discharge or the like. However, the welding method changes the structure of the welded part, so the size of the stress sensor must be larger than the size of the detection area of the magnetic head used to detect signals by the size of the heat-affected zone. There is.
【００１６】本発明の応力センサーの特徴は、被測定物
に流れる電流から発生する漏洩磁束や被測定物から漏洩
する電流があっても、磁気的な手法を用いて被測定物に
負荷される応力を精度良く測定できることである。以下
に応力センサー構造の限定理由について述べる。A feature of the stress sensor of the present invention is that even if there is a leakage magnetic flux generated from a current flowing through the object to be measured or a current leaking from the object to be measured, the stress is applied to the object to be measured using a magnetic method. That is, the stress can be accurately measured. The reasons for limiting the stress sensor structure will be described below.
【００１７】本発明による応力センサーは、被測定物に
貼り付ける面から数えた第一層目が非磁性材料からな
り、第二層目が強磁性材料からなる二層構造を持つこと
を特徴としている（図１）。The stress sensor according to the present invention is characterized by having a two-layer structure in which the first layer counted from the surface to be attached to the object to be measured is made of a non-magnetic material and the second layer is made of a ferromagnetic material. (Fig. 1).
【００１８】応力センサーの被測定物から数えた第一層
目に非磁性材料を配置するのは、被測定物と第二層目の
強磁性材料の間に磁気的な空隙を空けて、被測定物に流
れる電流から発生する磁束や被測定物の磁化から漏洩す
る磁束の第二層目の強磁性材料に対する磁気的な影響を
減少させるためである。磁気的な影響とは、被測定物か
ら発生する漏れ磁束により第二層目の強磁性材料が磁化
され、第二層目から検出する磁気信号が、該第二層の強
磁性材料の励磁磁化の大きさにより変化することを指
す。したがって、第一層目の非磁性材料による磁気的な
空隙は大きいほど、被測定物に流れる電流や磁束の影響
を排除する効果は大きい。The non-magnetic material is arranged in the first layer counted from the object to be measured of the stress sensor by forming a magnetic gap between the object to be measured and the ferromagnetic material in the second layer. This is to reduce the magnetic influence of the magnetic flux generated from the current flowing through the measured object or the magnetic flux leaked from the magnetization of the measured object on the ferromagnetic material of the second layer. The magnetic effect is that the leakage magnetic flux generated from the DUT magnetizes the ferromagnetic material of the second layer, and the magnetic signal detected from the second layer is the excitation magnetization of the ferromagnetic material of the second layer. Refers to the change in size. Therefore, the larger the magnetic gap formed by the non-magnetic material in the first layer, the greater the effect of eliminating the influence of the current or magnetic flux flowing in the object to be measured.
【００１９】他方、第一層目の非磁性材料には被測定物
に生じた歪みを第二層目の強磁性材料まで伝達させる役
割が同時にあるために、材質と厚みに制限がある。剛性
の観点から材質としては、金属系の非磁性材料，有機系
の樹脂材料，酸化物系の非磁性材料等が望ましい。ま
た、非磁性材料の厚みは５μｍ以上２０ｍｍ以下に限定
する。５μｍ未満の場合には被測定物から発生する漏れ
磁束の影響を受け易く、応力測定の精度が低下する。２
０ｍｍを超えると被測定物の歪みを十分に第二層目の強
磁性材料に伝えられなくなる。したがって、非磁性材料
の厚みは５μｍ以上２０ｍｍ以下に限定した。On the other hand, the nonmagnetic material of the first layer has a role of transmitting the strain generated in the object to be measured to the ferromagnetic material of the second layer at the same time, so that the material and the thickness thereof are limited. From the viewpoint of rigidity, a metal-based non-magnetic material, an organic resin material, an oxide-based non-magnetic material, or the like is desirable. Further, the thickness of the non-magnetic material is limited to 5 μm or more and 20 mm or less. If it is less than 5 μm, it is easily affected by the leakage magnetic flux generated from the object to be measured, and the accuracy of stress measurement decreases. Two
If it exceeds 0 mm, the strain of the measured object cannot be sufficiently transmitted to the ferromagnetic material of the second layer. Therefore, the thickness of the non-magnetic material is limited to 5 μm or more and 20 mm or less.
【００２０】応力センサーの被測定物から数えた第二層
目に強磁性材料を配置するのは、被測定物に負荷された
応力に相関を持つ磁気信号を発生するためである。材質
としては、パーマロイ，センダスト，ソフトフェライ
ト，Ｆｅ系アモルファス，Ｃｏ系アモルファス，炭素鋼
等の軟磁性の強磁性材料、が望ましい。該強磁性材料の
厚みは０．１μｍ以上１０ｍｍ以下に限定する。０．１
μｍ未満であると磁気ヘッドで検出できる磁気信号が著
しく低下し、実用的に十分な測定精度を得ることができ
ない。また、１０ｍｍを超えても、検出される磁気信号
の強度は変化しないので上限を１０ｍｍとした。The ferromagnetic material is arranged in the second layer of the stress sensor, which is counted from the object to be measured, in order to generate a magnetic signal having a correlation with the stress applied to the object to be measured. As the material, permalloy, sendust, soft ferrite, Fe-based amorphous, Co-based amorphous, and soft magnetic ferromagnetic material such as carbon steel are desirable. The thickness of the ferromagnetic material is limited to 0.1 μm or more and 10 mm or less. 0.1
If it is less than μm, the magnetic signal that can be detected by the magnetic head is significantly reduced, and practically sufficient measurement accuracy cannot be obtained. Further, even if it exceeds 10 mm, the strength of the detected magnetic signal does not change, so the upper limit was made 10 mm.
【００２１】さて、被測定物に電流が流れている場合に
は、応力センサーの強磁性材料に電流が流れ込む影響が
応力測定時に測定精度を低下させる原因となる。より高
い測定精度を得るためには次の応力センサーを用いると
効果的である。すなわち被測定物に貼り付ける面から数
えた第一層目が電気絶縁材料であり、第二層目が強磁性
材料からなる二層構造であることを特徴とする応力セン
サーである。When a current is flowing through the object to be measured, the influence of the current flowing into the ferromagnetic material of the stress sensor causes a decrease in measurement accuracy during stress measurement. In order to obtain higher measurement accuracy, it is effective to use the following stress sensor. That is, the stress sensor is characterized in that the first layer counted from the surface to be attached to the object to be measured has an electric insulating material and the second layer has a two-layer structure made of a ferromagnetic material.
【００２２】応力センサーの被測定物に貼り付ける面か
ら数えた第一層目に電気絶縁材料を配置するのは、第二
層目の強磁性材料に被測定物の電流の一部が流れ込まぬ
ようにするためである。第二層目の強磁性材料に電流が
流れ込むと強磁性材料の磁化状態が変化するので、電流
量の変化にともない応力測定時に検出する磁気信号が変
化し、測定の精度が低下する。ここで電気絶縁材料の厚
みは１μｍ以上５００μｍ以下に限定する。１μｍ未満
の場合には絶縁効果が低下し、応力測定精度が低下す
る。また、５００μｍを超えると絶縁効果は飽和する。
したがって、電気絶縁材料の厚みは１μｍ以上５００μ
ｍ以下に限定した。ここで電気絶縁材料の材質として
は、エポキシ系樹脂，フェノール系樹脂，酸化物材料等
が挙げられる。The electrical insulating material is arranged in the first layer counted from the surface of the stress sensor to be attached to the object to be measured, so that part of the current of the object to be measured does not flow into the ferromagnetic material in the second layer. To do so. When a current flows into the ferromagnetic material of the second layer, the magnetization state of the ferromagnetic material changes, so that the magnetic signal detected during stress measurement changes with a change in the amount of current, and the measurement accuracy decreases. Here, the thickness of the electrically insulating material is limited to 1 μm or more and 500 μm or less. If it is less than 1 μm, the insulation effect is lowered and the stress measurement accuracy is lowered. If it exceeds 500 μm, the insulating effect is saturated.
Therefore, the thickness of the electrically insulating material is 1 μm or more and 500 μm.
It was limited to m or less. Here, examples of the material of the electric insulating material include epoxy resin, phenol resin, oxide material and the like.
【００２３】被測定物に流れる電流から発生する漏れ磁
束の影響と被測定物から流れ込む電流の影響を同時に排
除する場合には、被測定物に貼り付ける面から数えた第
三層目が強磁性材料からなり、他の二層が非磁性材料お
よび電気絶縁性材料からなる三層構造を持つことを特徴
とする応力センサー（図２）を用いると効果的である。
特に、第一層目が電気絶縁性材料からなり、第二層目が
非磁性材料からなる構造の場合には、被測定物に流れる
電流と磁束の影響を十分に排除できるので、高い精度で
応力測定が可能である。また、三層それぞれの材質や厚
みに関しては前述した内容と同じである。When the influence of the leakage magnetic flux generated from the current flowing through the object to be measured and the influence of the current flowing into the object to be measured are simultaneously eliminated, the third layer counted from the surface to be bonded to the object to be measured is ferromagnetic. It is effective to use a stress sensor (FIG. 2) characterized by having a three-layer structure made of a material and the other two layers having a non-magnetic material and an electrically insulating material.
In particular, when the first layer is made of an electrically insulating material and the second layer is made of a non-magnetic material, the influence of the current and magnetic flux flowing in the DUT can be sufficiently eliminated, so that high accuracy can be achieved. It is possible to measure stress. The material and thickness of each of the three layers are the same as described above.
【００２４】さて、被測定物に貼り付ける面から数えた
第一層目が非磁性かつ電気絶縁性の材料からなり、第二
層目が強磁性材料からなる二層構造を特徴とする応力セ
ンサーを用いることによっても、電流の流れ込みと漏洩
磁束の電流の影響を同時に受けず、精度の高い応力測定
が可能である。第一層目の非磁性かつ電気絶縁性の材料
の厚みは、５μｍ以上２０ｍｍ以下に限定される。５μ
ｍ未満の場合には被測定物から発生する漏れ磁束の影響
を受け易く、応力測定の精度が低下する。２０ｍｍを超
えると被測定物の歪みを十分に第二層目の強磁性材料に
伝えられなくなる。したがって、非磁性かつ電気絶縁性
の材料の厚みは５μｍ以上２０ｍｍ以下に限定した。な
お、被測定物に強磁性材料からなる箔板をエポキシ系接
着剤のような非磁性かつ電気絶縁性の材料で接着厚みを
５μｍ以上２０ｍｍ以下にして接着した応力センサーも
本発明に含まれる。Now, a stress sensor characterized by a two-layer structure in which the first layer counted from the surface to be attached to the object to be measured is made of a non-magnetic and electrically insulating material and the second layer is made of a ferromagnetic material. Also by using, it is possible to measure the stress with high accuracy without being affected by the current inflow and the current of the leakage magnetic flux at the same time. The thickness of the non-magnetic and electrically insulating material of the first layer is limited to 5 μm or more and 20 mm or less. 5μ
If it is less than m, it is easily affected by the leakage magnetic flux generated from the object to be measured, and the accuracy of stress measurement decreases. If it exceeds 20 mm, the strain of the object to be measured cannot be sufficiently transmitted to the ferromagnetic material of the second layer. Therefore, the thickness of the non-magnetic and electrically insulating material is limited to 5 μm or more and 20 mm or less. It should be noted that the present invention also includes a stress sensor in which a foil plate made of a ferromagnetic material is adhered to the object to be measured with a nonmagnetic and electrically insulating material such as an epoxy adhesive with an adhesion thickness of 5 μm or more and 20 mm or less.
【００２５】以上のような本発明の応力センサーの製造
方法としては、それぞれの材料による箔板を用意し接着
により多層化する方法やクラッド圧延により多層化する
方法が挙げられる。また、メッキ法で多層化を行う方法
は生産性が高いので工業的な面で有利である。加えて、
スパッタ等の蒸着法でも本発明の応力センサーを製造す
ることが可能である。Examples of the method of manufacturing the stress sensor of the present invention as described above include a method of preparing a foil plate of each material and forming a multilayer by adhesion, and a method of forming a multilayer by clad rolling. In addition, the method of forming a multi-layer by the plating method has high productivity and is therefore advantageous from the industrial viewpoint. in addition,
The stress sensor of the present invention can be manufactured by a vapor deposition method such as sputtering.
【００２６】[0026]
【実施例】以下実施例に基づき、本発明を詳細に説明す
る。The present invention will be described in detail based on the following examples.
【００２７】（実施例１）鉄鋼材料を被測定物とした。
鋼材は１５０ｍｍ×１００ｍｍ×４００ｍｍの角棒であ
り、長手方向へ交流電流が流れるようにし、磁気的な手
法を用いた応力測定に該交流電流が与える影響について
調べた。応力測定に用いる磁気信号はバルクハウゼン信
号であり、被測定物に貼り付ける応力センサーは４５ｍ
ｍ×２５ｍｍの長方形板である。実験には、表１に示す
ような４種類の応力センサーを用意した。応力センサー
Ｎｏ．１，２，３（表１）については４５ｍｍ×２５ｍ
ｍの面に垂直な方向に多層化されている。貼り付ける被
測定物面から数えた第一層目、第二層目、第三層目の材
質とそれぞれの厚みを表１にまとめた。強磁性材料とし
ては、セメンタイトを球状化させた０．７％Ｃ炭素鋼材
を選んだ。ここで応力センサーＮｏ．１の第一層目と第
二層目の接合では、クラッド圧延法を用いた。また、応
力センサーＮｏ．２，３の第一層目と第二層目と第三層
目の接合には接着剤を用いた。Example 1 A steel material was used as an object to be measured.
The steel material was a rectangular bar of 150 mm × 100 mm × 400 mm, and an alternating current was made to flow in the longitudinal direction, and the influence of the alternating current on the stress measurement using a magnetic method was examined. The magnetic signal used for stress measurement is the Barkhausen signal, and the stress sensor attached to the measured object is 45 m.
It is a rectangular plate of m × 25 mm. Four types of stress sensors as shown in Table 1 were prepared for the experiment. Stress sensor No. 45mm x 25m for 1, 2 and 3 (Table 1)
It is multi-layered in the direction perpendicular to the plane of m. Table 1 shows the materials of the first layer, the second layer, and the third layer, which are counted from the surface of the measured object to be attached, and the respective thicknesses. As the ferromagnetic material, a 0.7% C carbon steel material obtained by spheroidizing cementite was selected. Here, the stress sensor No. In the joining of the first layer and the second layer of No. 1, the clad rolling method was used. In addition, the stress sensor No. An adhesive was used for joining the first layer, the second layer, and the third layer of Nos. 2 and 3.
【００２８】[0028]
【表１】 [Table 1]
【００２９】まず、表１に示したそれぞれの応力センサ
ーを角材の１５０ｍｍ×４００ｍｍの面に角材の長手方
向と応力センサーの長手方向が一致するように貼り付け
た。応力センサーＮｏ．２についてはエポキシ系接着剤
を用いて貼り付けたが、接着厚みは３μｍであった。応
力センサーＮｏ．１，３，４についてはアーク放電溶接
法にて貼り付けた。First, each of the stress sensors shown in Table 1 was attached to a 150 mm × 400 mm surface of a square bar so that the longitudinal direction of the square bar and the longitudinal direction of the stress sensor coincided with each other. Stress sensor No. No. 2 was attached using an epoxy adhesive, and the adhesive thickness was 3 μm. Stress sensor No. Nos. 1, 3 and 4 were attached by the arc discharge welding method.
【００３０】次に、角材に交流電流を流さない条件下に
おいて、角材の長手方向に圧縮応力を負荷し、それぞれ
の応力センサーから磁気ヘッドを用いてバルクハウゼン
信号を検出した。バルクハウゼン信号を検出する方法と
しては、励磁は１００Ｈｚの正弦波入力で応力方向と同
じ方向に行い、検出は検出ヘッドに誘起された磁気信号
のうち１０ｋＨｚ〜１００ｋＨｚのバルクハウゼン信号
を周波数フィルター装置にて分離して行った。そして、
圧縮応力を０〜−１５ｋｇ／ｍｍ2に変化させた場合の
バルクハウゼン信号の実効値電圧変化を調べ、バルクハ
ウゼン信号の負荷応力に対する検量線をそれぞれの応力
センサーについて作成した。Next, under the condition that an alternating current was not applied to the square bar, compressive stress was applied in the longitudinal direction of the square bar, and the Barkhausen signal was detected from each stress sensor using the magnetic head. As a method of detecting a Barkhausen signal, excitation is performed with a 100 Hz sine wave input in the same direction as the stress direction, and detection is performed by using a Barkhausen signal of 10 kHz to 100 kHz out of a magnetic signal induced in the detection head to a frequency filter device. And separated. And
The change in the effective value voltage of the Barkhausen signal when the compressive stress was changed to 0 to -15 kg / mm 2 was examined, and a calibration curve for the load stress of the Barkhausen signal was created for each stress sensor.
【００３１】そして角材の長手方向に交流電流を流した
条件下において、上述と同じ測定条件にてバルクハウゼ
ン信号を応力センサーから検出し、作成したそれぞれの
検量線を用いて応力に換算した。ここで交流電流の周波
数は５０Ｈｚであり、電流密度は２５Ａ／ｃｍ2であ
る。表２には、負荷圧縮応力が−１０ｋｇ／ｍｍ2の場
合に、それぞれの応力センサーにおいて応力測定を１０
回行い、そのばらつきについて得られた結果を示した。Then, under the condition that an alternating current was passed in the longitudinal direction of the square bar, the Barkhausen signal was detected from the stress sensor under the same measurement conditions as described above, and the stress was converted into the stress using the prepared respective calibration curves. Here, the frequency of the alternating current is 50 Hz and the current density is 25 A / cm 2 . Table 2 shows 10 stress measurements for each stress sensor when the load compressive stress is −10 kg / mm 2.
The results obtained for the variations were shown.
【００３２】[0032]
【表２】 [Table 2]
【００３３】表２から明らかなように、本発明の応力セ
ンサーＮｏ．１を用いた場合には、測定値のばらつきが
小さいことがわかる。さらに応力センサーＮｏ．２およ
び３を用いた場合には測定値のばらつきが極めて小さい
ことがわかる。他方、応力センサーＮｏ．４では測定毎
に測定値が大きく異なり、正確な応力値を求めることが
困難であることがわかった。As can be seen from Table 2, the stress sensor No. It can be seen that when 1 is used, the variation in measured values is small. Furthermore, the stress sensor No. It can be seen that when 2 and 3 are used, the dispersion of measured values is extremely small. On the other hand, the stress sensor No. It was found that it was difficult to obtain an accurate stress value because the measured value of No. 4 was greatly different for each measurement.
【００３４】以上の結果から、本発明の応力センサーを
用いることにより、被測定物に電流が流れていても磁気
的な手法を用いる応力測定が可能であることがわかっ
た。From the above results, it was found that by using the stress sensor of the present invention, it is possible to perform stress measurement using a magnetic method even when a current is flowing through the object to be measured.
【００３５】（実施例２）銅合金材を被測定物とした。
形状はφ３０ｍｍ×４５０ｍｍの円柱状であり、長手方
向へ交流電流が流れるようにし、磁気的な手法を用いた
応力測定に該交流電流が与える影響について調べた。Example 2 A copper alloy material was used as the object to be measured.
The shape was a cylindrical shape of φ30 mm × 450 mm, and an alternating current was made to flow in the longitudinal direction, and the influence of the alternating current on the stress measurement using a magnetic method was examined.
【００３６】応力センサーから発生する磁気信号から透
磁率を求めて、透磁率の変化から負荷される応力を求め
る。応力センサーは銅合金材の円柱側面に貼り付けられ
るように同じ曲率形状に加工される。ここで応力センサ
ーの寸法は、円柱の長手方向へは５０ｍｍであり、幅方
向へは５ｍｍである。実験には、表３に示すような３種
類の応力センサーＮｏ．５，６，７を用意した。ここで
応力センサーＮｏ．５については、厚み方向に三層で多
層化されている。また応力センサーＮｏ．６は、強磁性
材料をエポキシ系接着剤で被測定物へ貼り付けたもの
で、接着厚みが０．１ｍｍである二層構造を持つ応力セ
ンサーである。貼り付ける被測定物面から数えた第一層
目，第二層目，第三層目の材質とそれぞれの厚みを表３
にまとめた。第三層目に配置した強磁性材料としては、
パーマロイを選んだ。また、第一層目と第二層目、第二
層目と第三層目の接合には接着剤を用いた。The magnetic permeability is obtained from the magnetic signal generated from the stress sensor, and the applied stress is obtained from the change in the magnetic permeability. The stress sensor is processed to have the same curvature shape so as to be attached to the side surface of the cylinder of the copper alloy material. Here, the dimension of the stress sensor is 50 mm in the longitudinal direction of the cylinder and 5 mm in the width direction. In the experiment, three types of stress sensor No. 3 as shown in Table 3 were used. Prepared 5, 6 and 7. Here, the stress sensor No. As for No. 5, three layers are formed in the thickness direction. In addition, the stress sensor No. Reference numeral 6 is a stress sensor having a two-layer structure in which a ferromagnetic material is attached to an object to be measured with an epoxy adhesive and the adhesion thickness is 0.1 mm. Table 3 shows the materials of the first layer, the second layer, and the third layer counted from the object surface to be pasted and their respective thicknesses.
Summarized in. As the ferromagnetic material arranged in the third layer,
I chose Permalloy. An adhesive was used for joining the first layer and the second layer and the second layer and the third layer.
【００３７】[0037]
【表３】 [Table 3]
【００３８】応力センサーＮｏ．５についてはエポキシ
系接着剤を用いて銅合金材に用いて貼り付けたが、接着
厚みは３μｍであった。応力センサーＮｏ．７について
は放電スポット溶接にてパーマロイ板の周囲を溶接し
た。Stress sensor No. No. 5 was attached to a copper alloy material by using an epoxy adhesive, and the adhesive thickness was 3 μm. Stress sensor No. For No. 7, the perimeter of the permalloy plate was welded by discharge spot welding.
【００３９】次に、角材に交流電流を流さない条件下に
おいて、円柱形状材の長手方向に引っ張り応力を負荷
し、それぞれの応力センサーから磁気ヘッドを用いて磁
気信号を検出し、透磁率を求めた。透磁率を測定する方
法としては、励磁を４００Ｈｚの正弦波入力で引っ張り
応力方向と同じ方向に行い、検出ヘッドに誘起された電
圧波形から透磁率を算出した。そして、引っ張り応力を
０〜１５ｋｇ／ｍｍ2に変化した場合の透磁率変化を調
べ、透磁率の負荷応力に対する検量線をそれぞれの応力
センサーについて作成した。Next, under the condition that an alternating current is not applied to the square bar, a tensile stress is applied in the longitudinal direction of the columnar bar, and a magnetic signal is detected from each stress sensor using a magnetic head to obtain the magnetic permeability. It was As a method of measuring the magnetic permeability, excitation was performed with a sine wave input of 400 Hz in the same direction as the tensile stress direction, and the magnetic permeability was calculated from the voltage waveform induced in the detection head. Then, the change in magnetic permeability when the tensile stress was changed to 0 to 15 kg / mm 2 was examined, and a calibration curve for the applied stress of magnetic permeability was created for each stress sensor.
【００４０】円柱の長手方向に交流電流を流した条件下
で応力センサーから磁気信号を検出し、その時測定した
透磁率と作成したそれぞれの検量線を用いて応力に換算
した。ここで交流電流の周波数は５０Ｈｚであり、電流
密度は１０Ａ／ｃｍ2である。表４には負荷引っ張り応
力が１０ｋｇ／ｍｍ2の場合に、それぞれの応力センサ
ーにおいて応力測定を１０回行い、そのばらつきについ
て得られた結果を示した。A magnetic signal was detected from the stress sensor under the condition that an alternating current was passed in the longitudinal direction of the cylinder, and the magnetic permeability measured at that time and each calibration curve prepared were converted into stress. Here, the frequency of the alternating current is 50 Hz and the current density is 10 A / cm 2 . Table 4 shows the results obtained with respect to variations in stress measurement performed 10 times with each stress sensor when the load tensile stress was 10 kg / mm 2 .
【００４１】[0041]
【表４】 [Table 4]
【００４２】表４から明らかなように、本発明の応力セ
ンサーＮｏ．５およびＮｏ．６を用いた場合には、測定
値のばらつきが極めて小さいことがわかる。他方、応力
センサーＮｏ．７では測定毎に測定値が大きく異なり、
正確な応力値を求めることが困難であることがわかっ
た。As is clear from Table 4, the stress sensor Nos. 5 and No. It can be seen that when 6 is used, the variation in measured values is extremely small. On the other hand, the stress sensor No. In 7, the measured value is greatly different for each measurement,
It has been found that it is difficult to obtain an accurate stress value.
【００４３】以上の結果から、本発明の応力センサーを
用いることにより、被測定物に電流が流れていても磁気
的な手法を用いる応力測定が可能であることがわかっ
た。From the above results, it was found that by using the stress sensor of the present invention, it is possible to measure stress using a magnetic method even when a current is flowing through the object to be measured.
【００４４】[0044]
【発明の効果】以上の結果より、本発明の応力センサー
を用いることによって、被測定物に流れる電流や磁束に
影響されること無く磁気的な手法を用いた応力測定が可
能であることがわかる。本発明の応力センサーを用いる
ことにより、従来磁気的な手法を用いた応力測定が困難
であった鉄道設備，発電，送電，配電設備等においても
容易に応力測定が実施できるようになり、設備の保全や
安全確保が可能となる。From the above results, it can be seen that by using the stress sensor of the present invention, stress measurement using a magnetic method can be performed without being affected by the current or magnetic flux flowing in the object to be measured. . By using the stress sensor of the present invention, it becomes possible to easily perform stress measurement in railway equipment, power generation, power transmission, power distribution equipment, etc., where stress measurement using a magnetic method has been conventionally difficult. Maintenance and safety can be ensured.
【図１】 本発明の二層構造の応力センサーの層構成を
示す斜視図である。FIG. 1 is a perspective view showing a layer structure of a stress sensor having a two-layer structure of the present invention.
【図２】 本発明の三層構造の応力センサーの層構成を
示す斜視図である。FIG. 2 is a perspective view showing a layer structure of a stress sensor having a three-layer structure of the present invention.
Claims (8)
けて使用し、発生する磁気信号により応力を測定可能と
する応力センサーであって、 被測定物に貼り付ける面から数えた第一層目が非磁性材
料からなり、第二層目が強磁性材料からなる二層構造を
特徴とする応力センサー。1. A stress sensor, which is used by being attached to an object to be measured to measure stress and is capable of measuring stress by a generated magnetic signal, the first sensor being counted from the surface to be attached to the object to be measured. A stress sensor featuring a two-layer structure in which the second layer is made of a non-magnetic material and the second layer is made of a ferromagnetic material.
上２０ｍｍ以下であり、第二層目の強磁性材料の厚みが
０．１μｍ以上１０ｍｍ以下であることを特徴とする請
求項１に記載の応力センサー。2. The nonmagnetic material of the first layer has a thickness of 5 μm or more and 20 mm or less, and the ferromagnetic material of the second layer has a thickness of 0.1 μm or more and 10 mm or less. The stress sensor described in.
けて使用し、発生する磁気信号により応力を測定可能と
する応力センサーであって、 被測定物に貼り付ける面から数えた第一層目が電気絶縁
性材料からなり、第二層目が強磁性材料からなる二層構
造を特徴とする応力センサー。3. A stress sensor, which is used by being attached to an object to be measured to measure stress and is capable of measuring stress by a generated magnetic signal, the first sensor being counted from the surface to be attached to the object to be measured. A stress sensor characterized by a two-layer structure in which the second layer is made of an electrically insulating material and the second layer is made of a ferromagnetic material.
ｍ以上５００μｍ以下であり、第二層目の強磁性材料の
厚みが０．１μｍ以上１０ｍｍ以下であることを特徴と
する請求項３に記載の応力センサー。4. The thickness of the electrically insulating material of the first layer is 1 μm.
The stress sensor according to claim 3, wherein the second ferromagnetic material has a thickness of 0.1 μm or more and 10 μm or less.
けて使用し、発生する磁気信号により応力を測定可能と
する応力センサーであって、 被測定物に貼り付ける面から数えた第三層目が強磁性材
料からなり、他の二層が非磁性材料および電気絶縁性材
料からなる三層構造を特徴とする応力センサー。5. A stress sensor, which is used by being attached to an object to be measured to measure stress and is capable of measuring stress by a generated magnetic signal, the third sensor being counted from the surface to be attached to the object to be measured. A stress sensor characterized by a three-layer structure in which the second layer is made of a ferromagnetic material and the other two layers are made of a non-magnetic material and an electrically insulating material.
μｍ以下であり、非磁性材料の厚みが５μｍ以上２０ｍ
ｍ以下であり、強磁性材料の厚みが０．１μｍ以上１０
ｍｍ以下であることを特徴とする請求項５に記載の応力
センサー。6. The thickness of the electrically insulating material is 1 μm or more and 500.
The thickness of the non-magnetic material is 5 μm or more and 20 m or less.
The thickness of the ferromagnetic material is 0.1 μm or more and 10 or less.
The stress sensor according to claim 5, wherein the stress sensor is less than or equal to mm.
けて使用し、発生する磁気信号により応力を測定可能と
する応力センサーであって、 被測定物に貼り付ける面から数えた第一層目が非磁性か
つ電気絶縁性の材料からなり、第二層目が強磁性材料か
らなる二層構造を特徴とする応力センサー。7. A stress sensor, which is used by being attached to an object to be measured to measure stress, and which can measure stress by a magnetic signal generated, the first being counted from the surface to be attached to the object to be measured. A stress sensor characterized by a two-layer structure in which the second layer is made of a non-magnetic and electrically insulating material and the second layer is made of a ferromagnetic material.
μｍ以上２０ｍｍ以下であり、強磁性材料の厚みが０．
１μｍ以上１０ｍｍ以下であることを特徴とする請求項
７に記載の応力センサー。8. The thickness of the non-magnetic and electrically insulating material is 5
The thickness of the ferromagnetic material is 0.
The stress sensor according to claim 7, wherein the stress sensor is 1 μm or more and 10 mm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06289358A JP3078989B2 (en) | 1994-11-24 | 1994-11-24 | Stress sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06289358A JP3078989B2 (en) | 1994-11-24 | 1994-11-24 | Stress sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08145815A true JPH08145815A (en) | 1996-06-07 |
| JP3078989B2 JP3078989B2 (en) | 2000-08-21 |
Family
ID=17742179
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06289358A Expired - Lifetime JP3078989B2 (en) | 1994-11-24 | 1994-11-24 | Stress sensor |
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| Country | Link |
|---|---|
| JP (1) | JP3078989B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001295838A (en) * | 2000-04-12 | 2001-10-26 | Nsk Ltd | Bearing preload adjusting method and bearing structure |
| CN108759653A (en) * | 2018-07-25 | 2018-11-06 | 明阳智慧能源集团股份公司 | A kind of wind power generating set load strain monitoring device based on current vortex sensor |
-
1994
- 1994-11-24 JP JP06289358A patent/JP3078989B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001295838A (en) * | 2000-04-12 | 2001-10-26 | Nsk Ltd | Bearing preload adjusting method and bearing structure |
| CN108759653A (en) * | 2018-07-25 | 2018-11-06 | 明阳智慧能源集团股份公司 | A kind of wind power generating set load strain monitoring device based on current vortex sensor |
| CN108759653B (en) * | 2018-07-25 | 2023-12-22 | 明阳智慧能源集团股份公司 | Wind generating set load strain monitoring device based on eddy current sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3078989B2 (en) | 2000-08-21 |
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