JPH0861908A - Displacement detection device - Google Patents
Displacement detection deviceInfo
- Publication number
- JPH0861908A JPH0861908A JP20240294A JP20240294A JPH0861908A JP H0861908 A JPH0861908 A JP H0861908A JP 20240294 A JP20240294 A JP 20240294A JP 20240294 A JP20240294 A JP 20240294A JP H0861908 A JPH0861908 A JP H0861908A
- Authority
- JP
- Japan
- Prior art keywords
- magnetostrictive
- permanent magnet
- current pulse
- detection coil
- line
- 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
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
(57)【要約】
【目的】 本発明は変位検出装置に関し、回路構成部品
が少なくて済み、構成が簡単なことを目的とする。
【構成】 磁歪線２６は、磁歪材料で形成されており、
電流パルス発生部２８は、磁歪線に電流パルスを供給す
る。永久磁石３０は、磁歪線に対して相対変位して、磁
歪線に静的磁界を交差させる。検出コイル３１は、磁歪
線の所定位置に配設されている。検出回路は、検出コイ
ルで検出した電流パルスと、上記永久磁石と電流パルス
との相互作用による磁歪信号との時間差を検出して、上
記検出コイルと永久磁石との距離の変位を検出する。
(57) [Abstract] [Object] The present invention relates to a displacement detection device, and an object thereof is to reduce the number of circuit components and to simplify the configuration. [Structure] The magnetostrictive wire 26 is made of a magnetostrictive material,
The current pulse generator 28 supplies a current pulse to the magnetostrictive line. The permanent magnet 30 is relatively displaced with respect to the magnetostrictive line to cross the magnetostrictive line with a static magnetic field. The detection coil 31 is arranged at a predetermined position of the magnetostrictive wire. The detection circuit detects the time difference between the current pulse detected by the detection coil and the magnetostrictive signal due to the interaction between the permanent magnet and the current pulse, and detects the displacement of the distance between the detection coil and the permanent magnet.
Description
【０００１】[0001]
【産業上の利用分野】本発明は変位検出装置に関し、特
に磁歪現象を利用して変位量を検出する変位検出装置に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement detecting device, and more particularly to a displacement detecting device which detects a displacement amount by utilizing a magnetostriction phenomenon.
【０００２】[0002]
【従来の技術】従来から磁歪現象を利用して変位量を検
出する変位検出装置がある。例えば、特開昭５５−６６
７１０号公報に記載のものは、磁歪線に対して永久磁石
が変位する構造であり、磁歪線に励振パルスを流すと共
に、２つのフリップフロップをセットし、上記パルス電
流によって永久磁石位置で発生した超音波を磁歪線の両
端に設けた一対の受信手段で検出して、夫々に対応する
２つのフリップフロップを別々にリセットし、上記２つ
のフリップフロップ夫々が出力するパルスのパルス幅の
差から磁歪線に対する永久磁石の変位量を検出する。2. Description of the Related Art Conventionally, there is a displacement detection device that detects a displacement amount by utilizing a magnetostriction phenomenon. For example, JP-A-55-66
The structure described in Japanese Patent No. 710 has a structure in which a permanent magnet is displaced with respect to a magnetostrictive line, an excitation pulse is passed through the magnetostrictive line, two flip-flops are set, and the pulse current is generated at the permanent magnet position. The ultrasonic waves are detected by a pair of receiving means provided at both ends of the magnetostrictive line, and the two flip-flops corresponding to each are separately reset, and the magnetostriction is obtained from the difference in the pulse widths of the pulses output by the two flip-flops. The displacement of the permanent magnet with respect to the line is detected.
【０００３】[0003]
【発明が解決しようとする課題】従来装置は磁歪伝播速
度が周囲温度により変化するのを補償するために、一対
の検出手段及び２つのフリップフロップを必要とし、回
路構成部品が多く複雑であるという問題があった。The conventional device requires a pair of detection means and two flip-flops in order to compensate for the change in magnetostriction propagation speed due to the ambient temperature, and it is said that many circuit components are complicated. There was a problem.
【０００４】本発明は上記の点に鑑みなされたもので、
磁歪線に供給する電流パルスと永久磁石と電流パルスと
の相互作用による磁歪信号を単一の検出コイルで検出す
ることにより回路構成部品が少なくて済み、構成が簡単
な変位検出装置を提供することを目的とする。The present invention has been made in view of the above points,
To provide a displacement detection device having a simple configuration, in which the number of circuit components can be reduced by detecting a magnetostrictive signal due to the interaction between a current pulse supplied to a magnetostrictive wire and a permanent magnet and a current pulse with a single detection coil. With the goal.
【０００５】[0005]
【課題を解決するための手段】請求項１記載の発明は、
磁歪材料で形成した磁歪線と、上記磁歪線に電流パルス
を供給する電流パルス発生部と、上記磁歪線に対して相
対変位して、上記磁歪線に静的磁界を交差させる永久磁
石と、上記磁歪線の所定位置に配設された検出コイル
と、上記検出コイルで検出した電流パルスと、上記永久
磁石と電流パルスとの相互作用による磁歪信号との時間
差を検出して、上記検出コイルと永久磁石との距離の変
位を検出する検出回路とを有する。According to the first aspect of the present invention,
A magnetostrictive line formed of a magnetostrictive material, a current pulse generator that supplies a current pulse to the magnetostrictive line, a relative magnet that is relatively displaced with respect to the magnetostrictive line, and crosses a static magnetic field to the magnetostrictive line, and The detection coil disposed at a predetermined position of the magnetostrictive wire, the current pulse detected by the detection coil, and the time difference between the magnetostriction signal due to the interaction between the permanent magnet and the current pulse are detected to detect the And a detection circuit for detecting displacement of the distance to the magnet.
【０００６】請求項２に記載の発明では、前記磁歪線は
導電性材料で形成された筒体内に配設されており、上記
磁歪線の外周面に酸化被膜を形成する。According to a second aspect of the present invention, the magnetostrictive wire is disposed inside a cylinder made of a conductive material, and an oxide film is formed on the outer peripheral surface of the magnetostrictive wire.
【０００７】請求項３に記載の発明では、前記筒体は、
ショックアブソーバのアブソーバロッドの内部に設けて
あり、前記永久磁石は上記ショックアブソーバのアブソ
ーバシリンダに固定されており、上記永久磁石の両極を
挟む軟磁性材を有し、車両の車高を測定する。In the invention according to claim 3, the cylindrical body is
The permanent magnet is provided inside the absorber rod of the shock absorber, the permanent magnet is fixed to the absorber cylinder of the shock absorber, and has a soft magnetic material sandwiching both poles of the permanent magnet to measure the vehicle height of the vehicle.
【０００８】[0008]
【作用】請求項１に記載の発明においては、検出コイル
で磁歪線の電流パルスと磁歪信号とを検出するため、検
出コイルが１つで済み、回路構成部品が少なくて済み、
構成が簡単となる。According to the first aspect of the invention, since the detection coil detects the current pulse and the magnetostriction signal of the magnetostrictive line, only one detection coil is required and the number of circuit components is reduced.
The configuration is simple.
【０００９】請求項２に記載の発明においては、磁歪線
に酸化被膜を形成することにより、筒体との絶縁を行う
ことができ、筒体の磁歪線配設スペースを小さくでき、
かつ酸化被膜形成時の加熱により磁歪線の加工歪も低減
できる。According to the second aspect of the present invention, by forming an oxide film on the magnetostrictive wire, it is possible to insulate the magnetostrictive wire from the cylinder and to reduce the space for disposing the magnetostrictive wire in the cylinder.
In addition, the processing strain of the magnetostrictive wire can be reduced by heating when forming the oxide film.
【００１０】請求項３に記載の発明においては、軟磁性
材で永久磁石の両極を挟むことにより、永久磁石からの
磁束を筒体に向けて集中的に出し、アブソーバロッドが
磁性材料であっても永久磁石の磁界を磁歪線に有効に交
差させることができる。According to the third aspect of the invention, by sandwiching both poles of the permanent magnet with a soft magnetic material, the magnetic flux from the permanent magnet is concentratedly directed toward the cylindrical body, and the absorber rod is a magnetic material. Can effectively intersect the magnetic field of the permanent magnet with the magnetostrictive line.
【００１１】[0011]
【実施例】図２は本発明装置の一実施例の構成図を示
す。この実施例は変位検出装置をエアサスペンションの
ショックアブソーバに車高センサとして適用している。FIG. 2 is a block diagram of an embodiment of the device of the present invention. In this embodiment, the displacement detecting device is applied to a shock absorber of an air suspension as a vehicle height sensor.
【００１２】同図中、アブソーバシリンダ１１とサスタ
ワー（図示せず）との間には高圧のエアを封入するメイ
ンエアチャンバ１２及びサブエアチャンバ１３が形成さ
れている。アブソーバシリンダ１１は上下動するため、
メインエアチャンバ１２とアブソーバシリンダ１１とは
フレキシブル樹脂で形成されたダイヤフラム１５で連結
されている。In the figure, a main air chamber 12 and a sub air chamber 13 for enclosing high-pressure air are formed between an absorber cylinder 11 and a suspension tower (not shown). Since the absorber cylinder 11 moves up and down,
The main air chamber 12 and the absorber cylinder 11 are connected by a diaphragm 15 made of flexible resin.
【００１３】ショックアブソーバの減衰力制御はピスト
ン２０内に設けられた可変オリフィスを切換えることに
より行われる。ピストン２０で仕切られたアブソーバシ
リンダ１１内の上下室のオイルが、アブソーバシリンダ
１１の上下動に伴い、可変オリフィスを通して移動する
ことにより減衰力が発生する。従って、オリフィスの径
を可変して減衰力を増減させる。The damping force control of the shock absorber is performed by switching the variable orifice provided in the piston 20. The oil in the upper and lower chambers inside the absorber cylinder 11 partitioned by the piston 20 moves through the variable orifice as the absorber cylinder 11 moves up and down, so that a damping force is generated. Therefore, the diameter of the orifice is changed to increase or decrease the damping force.
【００１４】減衰力切換機構は、アブソーバロッド２２
内に配設されているコントロールロッド２３を回転させ
てオリフィスの径を切換える。このため、アブソーバロ
ッド２２の上部に減衰力切換アクチュエータ２５が配設
されている。The damping force switching mechanism includes an absorber rod 22.
The diameter of the orifice is switched by rotating the control rod 23 disposed inside. Therefore, the damping force switching actuator 25 is arranged above the absorber rod 22.
【００１５】また、アブソーバロッド２２内には内部に
磁歪線２６を備える筒体２７が配設されている。筒体２
７の上部には電流パルス発生部２８が設けられ、ここで
発生した電流パルスが磁歪線２６に供給される。アブソ
ーバシリンダ１１の上部にはリング状の永久磁石３０が
アブソーバロッド２２に挿通された状態で配設固定され
ている。更に、電流パルス発生部２８が設けられた側の
内部に磁歪線２６を備える筒体２７の端部には検出コイ
ル３１が磁歪線２６を周回する状態で配設されている。A cylindrical body 27 having a magnetostrictive wire 26 therein is disposed inside the absorber rod 22. Cylinder 2
A current pulse generator 28 is provided on the upper part of 7, and the current pulse generated here is supplied to the magnetostrictive line 26. On the upper part of the absorber cylinder 11, a ring-shaped permanent magnet 30 is arranged and fixed while being inserted into the absorber rod 22. Further, a detection coil 31 is arranged at the end of the cylinder 27 having the magnetostrictive wire 26 inside the side on which the current pulse generator 28 is provided, in a state of circling the magnetostrictive wire 26.
【００１６】ここで、車高が変化し、メインエアチャン
バ１２の容量が変化すると、それと共にピストン２０が
アブソーバシリンダ１１内を上下するので検出コイル３
１から永久磁石３０までの間の磁歪線２６の長さが変化
する。Here, when the vehicle height changes and the capacity of the main air chamber 12 changes, the piston 20 moves up and down in the absorber cylinder 11 accordingly, so that the detection coil 3
The length of the magnetostrictive line 26 between 1 and the permanent magnet 30 changes.
【００１７】磁歪線２６はＦｅ−Ｎｉ又はＦｅ−Ｃｏ等
を主成分とした、温度による密度変化の極めて小さな軟
質磁性材料を用いる。特にＮｉ４５〜５０−Ｆｅは−１
００〜４００℃の温度範囲で熱膨脹係数が略一定で磁歪
伝達速度の変化が極めて小さい。The magnetostrictive wire 26 is made of a soft magnetic material containing Fe-Ni or Fe-Co as a main component and having a very small density change with temperature. Especially Ni45-50-Fe is -1
The coefficient of thermal expansion is substantially constant in the temperature range of 00 to 400 ° C, and the change in magnetostriction transmission speed is extremely small.
【００１８】図３（Ａ）に示す如く、磁歪線２６は導電
性の非磁性材料で形成された筒体２７内に配設され、磁
歪線２６の一端２６ａと筒体２７の一端２７ａとを接続
し、磁歪線２６の他端２６ｂと筒体２７の他端２７ｂと
の間にパルス発生部２８を接続して磁歪線２６に電流パ
ルスを供給するため、磁歪線２６と筒体２７との間は両
者の一端２６ａ，２７ａを除いて絶縁をとる必要があ
る。As shown in FIG. 3A, the magnetostrictive wire 26 is disposed inside a cylindrical body 27 made of a conductive non-magnetic material, and one end 26a of the magnetostrictive wire 26 and one end 27a of the cylindrical body 27 are connected to each other. Since the pulse generator 28 is connected between the other end 26b of the magnetostrictive wire 26 and the other end 27b of the tubular body 27 to supply a current pulse to the magnetostrictive wire 26, the magnetostrictive wire 26 and the tubular body 27 are connected to each other. Between the two, it is necessary to insulate both ends except for one end 26a, 27a.
【００１９】このため、図３（Ｂ）に示す如く磁歪線２
６の外周面に酸化被膜４０を形成して絶縁を行う。磁歪
線２６の製造時に冷間加工を行うと加工歪が発生し磁歪
効果も小さくなる。この加工歪を除くための焼鈍加工時
に酸化被膜４０を同時に形成し、加工歪も低減させる。
このように酸化被膜４０を形成した磁歪線２６は別途絶
縁材を設ける必要がないため、筒体２７の磁歪線収容ス
ペースを小さくでき、図３（Ｃ），（Ｄ）夫々に示す如
く磁歪線２６を筒体２７の一部に埋め込む構造とするこ
とも可能となる。Therefore, as shown in FIG.
An oxide film 40 is formed on the outer peripheral surface of 6 for insulation. If cold working is performed at the time of manufacturing the magnetostrictive wire 26, working distortion occurs and the magnetostrictive effect also decreases. The oxide film 40 is simultaneously formed during the annealing process for removing the processing strain, and the processing strain is also reduced.
Since the magnetostrictive wire 26 thus formed with the oxide film 40 does not need to be provided with an insulating material separately, the space for accommodating the magnetostrictive wire in the cylindrical body 27 can be reduced, and the magnetostrictive wire can be formed as shown in FIGS. 3 (C) and (D). It is also possible to have a structure in which 26 is embedded in a part of the cylindrical body 27.
【００２０】ところで、永久磁石３０は静的磁界を磁歪
線２６に交差させるために設けられているが、図４
（Ａ）に示す如く永久磁石３０と磁歪線２６を内部に備
えた筒体２７との間には磁性材料のアブソーバロッド２
２が存在する。この場合、永久磁石３０からアブソーバ
ロッド２２の長手方向に沿って出た磁束の大半は磁気抵
抗の小さなアブソーバロッド２２を通る磁気ループを形
成し、わずかの磁束が磁歪線２６及び筒体２７に交差す
るだけとなる。By the way, the permanent magnet 30 is provided for intersecting the static magnetic field with the magnetostrictive line 26.
As shown in (A), the absorber rod 2 made of a magnetic material is provided between the permanent magnet 30 and the cylindrical body 27 having the magnetostrictive wire 26 therein.
There are two. In this case, most of the magnetic flux emitted from the permanent magnet 30 along the longitudinal direction of the absorber rod 22 forms a magnetic loop passing through the absorber rod 22 having a small magnetic resistance, and a slight magnetic flux intersects the magnetostrictive line 26 and the cylindrical body 27. It will only be done.
【００２１】そこで、図４（Ｂ）に示す如く永久磁石３
０の両極を軟磁性材３３，３４で挟持する。これによ
り、永久磁石３０の磁束の大半は軟磁性材３３，３４か
らアブソーバロッド２２の軸方向に出て、これに対向す
るアブソーバロッド２２を通る磁気ループを形成し、磁
束が軟磁性材３３，３４に集中するため、多くの磁束が
漏洩して永久磁石の磁界を有効に磁歪線２６及び筒体２
７に交差させることができる。これによって磁歪線２６
に生じる機械的ねじれを大きくでき、検出コイル３１で
検出される磁歪信号のレベルが大きくなる。Therefore, as shown in FIG. 4B, the permanent magnet 3
Both poles of 0 are sandwiched by the soft magnetic materials 33 and 34. As a result, most of the magnetic flux of the permanent magnet 30 exits from the soft magnetic materials 33 and 34 in the axial direction of the absorber rod 22, forms a magnetic loop passing through the absorber rod 22 facing the soft magnetic material 33, 34, and the magnetic flux is Since it concentrates on 34, a large amount of magnetic flux leaks and the magnetic field of the permanent magnet is effectively made effective for the magnetostrictive line 26 and the cylindrical body 2.
You can cross to 7. As a result, the magnetostrictive line 26
It is possible to increase the mechanical twist that occurs in (1), and the level of the magnetostrictive signal detected by the detection coil 31 increases.
【００２２】ここで、電流パルス発生部２８で発生した
電流パルスを磁歪線２６に供給すると、この電流パルス
により磁歪線２６に円周方向の局所的磁場が形成され、
電流パルスが磁歪線２６の軸方向下方へ瞬時に伝播する
に伴い、上記円周方向の磁場は軸方向に発生する。上記
電流パルスが検出コイル３１の設置位置を通るとき、検
出コイル３１には起電力が生じる。When the current pulse generated by the current pulse generator 28 is supplied to the magnetostrictive line 26, the current pulse forms a local magnetic field in the circumferential direction on the magnetostrictive line 26,
As the current pulse instantaneously propagates downward in the axial direction of the magnetostrictive line 26, the magnetic field in the circumferential direction is generated in the axial direction. When the current pulse passes through the installation position of the detection coil 31, an electromotive force is generated in the detection coil 31.
【００２３】この円周方向の磁場が永久磁石３０による
軸方向の磁場とぶつかることにより磁歪線２６をねじる
方向に合成磁場が形成される。磁歪材は磁場を与えると
磁力線方向に歪を生じ、逆に機械的歪を与えると歪方向
に磁化される物理的性質を持っている。このため、永久
磁石３０配置位置において磁歪線２６に機械的ねじれが
発生し、この機械的ねじれは磁歪線２６の磁化を伴って
磁歪線２６上をアブソーバロッド２２の上下方向に伝播
し、検出コイル３１の設置位置まで到達する。検出コイ
ル３１には磁歪線２６の機械的ねじれに伴う磁化により
起電力が生じる。The magnetic field in the circumferential direction collides with the magnetic field in the axial direction by the permanent magnet 30 to form a composite magnetic field in the direction in which the magnetostrictive line 26 is twisted. The magnetostrictive material has a physical property of being distorted in the direction of the magnetic force line when a magnetic field is applied, and conversely magnetized in the strain direction when a mechanical strain is applied. Therefore, a mechanical twist is generated in the magnetostrictive line 26 at the position where the permanent magnet 30 is arranged, and this mechanical twist propagates on the magnetostrictive line 26 in the up-down direction of the absorber rod 22 along with the magnetization of the magnetostrictive line 26, and the detection coil The installation position of 31 is reached. An electromotive force is generated in the detection coil 31 due to the magnetization accompanying the mechanical twist of the magnetostrictive wire 26.
【００２４】図１は検出回路の一実施例の回路図を示
す。同図中、検出コイル３１と並列に抵抗Ｒ1 及びコン
デンサＣ1 が接続され、発振回路を構成している。磁歪
線２６に電流パルスを流すと、検出コイル３１には電流
パルスの一次微分の誘導起電力が発生し、また磁歪線２
６の機械的ねじれに伴う誘導起電力が発生する。FIG. 1 shows a circuit diagram of an embodiment of the detection circuit. In the figure, a resistor R 1 and a capacitor C 1 are connected in parallel with the detection coil 31 to form an oscillation circuit. When a current pulse is passed through the magnetostrictive line 26, an induced electromotive force of the first derivative of the current pulse is generated in the detection coil 31, and the magnetostrictive line 2 is generated.
An induced electromotive force is generated due to the mechanical twist of No. 6.
【００２５】上記検出コイル３１の誘導起電力は次式で
表わされる。The induced electromotive force of the detection coil 31 is expressed by the following equation.
【００２６】[0026]
【数１】 [Equation 1]
【００２７】但し、ａ1 ，ａ2 はコイルの内半径、外半
径、Ｌはコイル長、Ｎは総巻数、ｍは磁化量、Ｖは磁歪
伝達速度である。Here, a 1 and a 2 are the inner and outer radii of the coil, L is the coil length, N is the total number of turns, m is the amount of magnetization, and V is the magnetostriction transmission speed.
【００２８】これによって、上記発振回路の出力電圧を
増幅したバッファ４０の出力信号は図５（Ａ）に示す如
くなる。ここで、Ｐ１が電流パルスの検出信号、Ｐ２が
機械的ねじれの検出信号である。As a result, the output signal of the buffer 40 obtained by amplifying the output voltage of the oscillation circuit becomes as shown in FIG. 5 (A). Here, P1 is a current pulse detection signal, and P2 is a mechanical twist detection signal.
【００２９】この図５（Ａ）に示す検出信号ａはコンパ
レータ４１において基準値と比較されて、図５（Ｂ）に
示すパルス信号ｂに整形される。パルス信号ｂはＤ形フ
リップフロップ４２のＱ端子出力をデータ入力端子Ｄに
フィードバックして構成したＴ形フリップフロップによ
り１／２分周されて図５（Ｃ）に示すパルス信号Ｃとさ
れる。パルス信号Ｃは検出信号Ｐ１時点で立下り、検出
信号Ｐ２時点で立上るパルスである。The detection signal a shown in FIG. 5A is compared with the reference value in the comparator 41 and shaped into the pulse signal b shown in FIG. 5B. The pulse signal b is divided in half by a T-type flip-flop configured by feeding back the Q terminal output of the D-type flip-flop 42 to the data input terminal D to obtain a pulse signal C shown in FIG. 5C. The pulse signal C is a pulse which falls at the time of the detection signal P1 and rises at the time of the detection signal P2.
【００３０】パルス信号ｃはトランジスタ４３のベース
に供給される。トランジスタ４３はパルス信号ｃのロー
レベル期間に遮断し、コンデンサＣ2 は抵抗Ｒ2 を通し
て時定数Ｃ2 ・Ｒ2 で充電される。これによってトラン
ジスタ４３のコレクタ電圧は図５（Ｄ）に示す如くパル
ス信号ｃのローレベル期間が長いほど上昇する。これと
共に、パルス信号ｃはコンデンサＣ3 とダイオードＤ1
と、抵抗Ｒ3 とで構成される微分回路に供給され、パル
ス信号ｃの立上りを検出した図５（Ｅ）に示す立上りエ
ッジパルスｅが生成される。The pulse signal c is supplied to the base of the transistor 43. The transistor 43 cuts off during the low level period of the pulse signal c, and the capacitor C 2 is charged with the time constant C 2 · R 2 through the resistor R 2 . As a result, the collector voltage of the transistor 43 increases as the low level period of the pulse signal c increases as shown in FIG. At the same time, the pulse signal c has a capacitor C 3 and a diode D 1
And a resistor R 3 are supplied to the differentiating circuit to generate the rising edge pulse e shown in FIG. 5E in which the rising edge of the pulse signal c is detected.
【００３１】ＦＥＴ４４，４５と、コンデンサＣ4 と、
抵抗Ｒ4 とバッファ４６とでサンプルホールド回路が構
成されている。立上りエッジパルスｅの発生時点でサン
プルホールド回路はトランジスタＱのコレクタ電圧を図
５（Ｆ）に示す如くサンプリングホールドし端子４７よ
り出力する。つまり、このホールド電圧は検出信号Ｐ１
から検出信号Ｐ２までの期間に応じた電圧となる。FETs 44 and 45, a capacitor C 4 , and
The resistor R 4 and the buffer 46 form a sample hold circuit. When the rising edge pulse e is generated, the sample and hold circuit samples and holds the collector voltage of the transistor Q as shown in FIG. That is, the hold voltage is the detection signal P1.
To a detection signal P2.
【００３２】このように本実施例では検出コイル３１で
電流パルス及び磁歪信号を検出するため、磁歪線に電流
パルスを供給してから超音波が発生するまでの遅れが生
じることはなく、かつ回路構成部品数が従来より少なく
て済み、構成が簡単となる。As described above, in the present embodiment, since the detection coil 31 detects the current pulse and the magnetostrictive signal, there is no delay between the supply of the current pulse to the magnetostrictive line and the generation of the ultrasonic wave, and the circuit. The number of components is smaller than before, and the configuration is simple.
【００３３】[0033]
【発明の効果】上述の如く、請求項１に記載の発明によ
れば、検出コイルで磁歪線の電流パルスと磁歪信号とを
検出するため、検出コイルが１つで済み、回路構成部品
が少なくて済み、構成が簡単となる。As described above, according to the first aspect of the invention, since the detection coil detects the current pulse and the magnetostriction signal of the magnetostrictive line, only one detection coil is required and the number of circuit components is small. The configuration is simple.
【００３４】また、請求項２に記載の発明によれば、磁
歪線に酸化被膜を形成することにより、筒体との絶縁を
行うことができ、筒体の磁歪線配設スペースを小さくで
き、かつ酸化被膜形成時の加熱により磁歪線の加工歪も
低減できる。According to the second aspect of the present invention, by forming an oxide film on the magnetostrictive wire, it is possible to insulate the magnetostrictive wire from the cylindrical body and reduce the space for disposing the magnetostrictive wire in the cylindrical body. In addition, the processing strain of the magnetostrictive wire can be reduced by heating when forming the oxide film.
【００３５】また、請求項３に記載の発明によれば、軟
磁性材で永久磁石の両極を挟むことにより、永久磁石か
らの磁束を筒体に向けて集中的に出し、アブソーバロッ
ドが磁性材料であっても永久磁石の磁界を磁歪線に有効
に交差させることができ、磁歪現象による磁歪線の機械
的ねじれを大きくでき、検出コイルで検出される磁歪信
号のレベルが大きくなり、実用上きわめて有用である。According to the third aspect of the present invention, by sandwiching both poles of the permanent magnet with the soft magnetic material, the magnetic flux from the permanent magnet is concentrated toward the cylindrical body, and the absorber rod is made of the magnetic material. However, the magnetic field of the permanent magnet can be effectively crossed with the magnetostrictive line, the mechanical distortion of the magnetostrictive line due to the magnetostriction phenomenon can be increased, and the level of the magnetostrictive signal detected by the detection coil can be increased. It is useful.
【図１】本発明装置の検出回路の回路図である。FIG. 1 is a circuit diagram of a detection circuit of a device of the present invention.
【図２】本発明装置の構成図である。FIG. 2 is a configuration diagram of the device of the present invention.
【図３】本発明装置の磁歪線を説明するための図であ
る。FIG. 3 is a diagram for explaining a magnetostrictive line of the device of the present invention.
【図４】本発明装置の永久磁石及び軟磁性材を説明する
ための図である。FIG. 4 is a diagram for explaining a permanent magnet and a soft magnetic material of the device of the present invention.
【図５】図１の回路各部の信号タイミングチャートであ
る。5 is a signal timing chart of each part of the circuit of FIG.
１１ アブソーバシリンダ １２ メインエアチャンバ １３ サブエアチャンバ ２０ ピストン ２２ アブソーバロッド ２３ コントロールロッド ２５ アクチュエータ ２６ 磁歪線 ２７ 筒体 ２８ 電流パルス発生部 ３０ 永久磁石 ３１ 検出コイル ３３，３４ 軟磁性材 ４０ 酸化被膜 11 Absorber Cylinder 12 Main Air Chamber 13 Sub Air Chamber 20 Piston 22 Absorber Rod 23 Control Rod 25 Actuator 26 Magnetostrictive Wire 27 Cylindrical Body 28 Current Pulse Generating Part 30 Permanent Magnet 31 Detection Coil 33, 34 Soft Magnetic Material 40 Oxidized Film
Claims (3)
と、 上記磁歪線に対して相対変位して、上記磁歪線に静的磁
界を交差させる永久磁石と、 上記磁歪線の所定位置に配設された検出コイルと、 上記検出コイルで検出した電流パルスと、上記永久磁石
と電流パルスとの相互作用による磁歪信号との時間差を
検出して、上記検出コイルと永久磁石との距離の変位を
検出する検出回路とを有することを特徴とする変位検出
装置。1. A magnetostrictive line formed of a magnetostrictive material, a current pulse generator that supplies a current pulse to the magnetostrictive line, and a relative displacement with respect to the magnetostrictive line to cross a static magnetic field on the magnetostrictive line. A permanent magnet, a detection coil arranged at a predetermined position of the magnetostrictive wire, a current pulse detected by the detection coil, and a time difference between a magnetostrictive signal due to the interaction between the permanent magnet and the current pulse is detected, A displacement detection device comprising: a detection circuit that detects displacement of the distance between the detection coil and the permanent magnet.
体内に配設されており、上記磁歪線の外周面に酸化被膜
を形成したことを特徴とする請求項１記載の変位検出装
置。2. The displacement detecting device according to claim 1, wherein the magnetostrictive wire is arranged in a cylindrical body made of a conductive material, and an oxide film is formed on an outer peripheral surface of the magnetostrictive wire. .
ソーバロッドの内部に設けてあり、前記永久磁石は上記
ショックアブソーバのアブソーバシリンダに固定されて
おり、 上記永久磁石の両極を挟む軟磁性材を有し、 車輛の車高を測定することを特徴とする請求項２記載の
変位検出装置。3. The cylindrical body is provided inside an absorber rod of a shock absorber, the permanent magnet is fixed to an absorber cylinder of the shock absorber, and a soft magnetic material sandwiching both poles of the permanent magnet is provided. The displacement detecting device according to claim 2, wherein the vehicle height of the vehicle is measured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6202402A JP3060845B2 (en) | 1994-08-26 | 1994-08-26 | Displacement detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6202402A JP3060845B2 (en) | 1994-08-26 | 1994-08-26 | Displacement detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0861908A true JPH0861908A (en) | 1996-03-08 |
| JP3060845B2 JP3060845B2 (en) | 2000-07-10 |
Family
ID=16456916
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6202402A Expired - Lifetime JP3060845B2 (en) | 1994-08-26 | 1994-08-26 | Displacement detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3060845B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1015890A (en) * | 1996-07-04 | 1998-01-20 | Meisan Kk | Positioning device such as slitter |
| CN109357611A (en) * | 2018-10-31 | 2019-02-19 | 柳州钢铁股份有限公司 | Magnetostrictive displacement sensor detection and calibration device |
-
1994
- 1994-08-26 JP JP6202402A patent/JP3060845B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1015890A (en) * | 1996-07-04 | 1998-01-20 | Meisan Kk | Positioning device such as slitter |
| CN109357611A (en) * | 2018-10-31 | 2019-02-19 | 柳州钢铁股份有限公司 | Magnetostrictive displacement sensor detection and calibration device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3060845B2 (en) | 2000-07-10 |
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