JPH08114515A - Magnetostriction type torque sensor - Google Patents
Magnetostriction type torque sensorInfo
- Publication number
- JPH08114515A JPH08114515A JP25094994A JP25094994A JPH08114515A JP H08114515 A JPH08114515 A JP H08114515A JP 25094994 A JP25094994 A JP 25094994A JP 25094994 A JP25094994 A JP 25094994A JP H08114515 A JPH08114515 A JP H08114515A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetostrictive
- torque
- coil
- rotating shaft
- 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.)
- Withdrawn
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Landscapes
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は回転体のトルクを測定す
る磁歪式トルクセンサに係り、特に磁歪式トルクセンサ
の温度変化に対するトルク測定精度の改善に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostrictive torque sensor for measuring the torque of a rotating body, and more particularly to improving the torque measurement accuracy of the magnetostrictive torque sensor with respect to temperature changes.
【０００２】[0002]
【従来の技術】モータ等の回転体のトルクを測定する方
法として、今日、ピエゾ素子、半導体圧電素子、磁歪セ
ンサ、等の各種センサが開発され、回転体のトルク測定
にこれらの小型のトルクセンサが用いられている。しか
し、回転体に直接取り付け、回転体に生ずる歪みを電圧
変化として取り出すピエゾ素子では、素子から電圧出力
を得る為、例えば回転体にスリップリング等を取り付け
る必要があり、装置が複雑となる。この点、磁歪センサ
は回転体に生じる応力を磁界の変化として検出し、回転
体と非接触で回転体にかかるトルクを測定することがで
きる利点を有する。2. Description of the Related Art Today, various sensors such as a piezo element, a semiconductor piezoelectric element, and a magnetostrictive sensor have been developed as a method for measuring the torque of a rotating body such as a motor. Is used. However, in the piezo element that is directly attached to the rotating body and takes out the strain generated in the rotating body as a voltage change, a voltage output is obtained from the element, so that a slip ring or the like needs to be attached to the rotating body, which complicates the device. In this respect, the magnetostrictive sensor has an advantage that it can detect the stress generated in the rotating body as a change in the magnetic field and measure the torque applied to the rotating body without contacting the rotating body.
【０００３】図４は、上述の磁歪センサを用いたトルク
センサの断面図である。同図において、回転軸１は測定
する回転体の軸が連結する部材であり、回転軸１には磁
歪膜２及び３が形成されている。磁歪膜２、３の周面近
傍にはハウジング４に収納されたコイル５、６が配設さ
れている。このコイル５、６はコイルボビンに巻装され
ヨーク７に取り付けられており、このヨーク７は絶縁部
材８を介してハウジング４に取り付けられている。FIG. 4 is a sectional view of a torque sensor using the above-mentioned magnetostrictive sensor. In the figure, a rotating shaft 1 is a member to which the shaft of a rotating body to be measured is connected, and the rotating shaft 1 is provided with magnetostrictive films 2 and 3. Coils 5 and 6 housed in a housing 4 are arranged near the peripheral surfaces of the magnetostrictive films 2 and 3. The coils 5 and 6 are wound around a coil bobbin and attached to a yoke 7. The yoke 7 is attached to the housing 4 via an insulating member 8.
【０００４】上述の構成の磁歪式トルクセンサにおい
て、ヨーク７は磁歪式トルクセンサに組み込む前は、図
５に示す様に所謂２つ割り構成であり（尚、図５（ａ）
は正面図であり、図５（ｂ）はその側面図である）、ヨ
ーク７ａ、７ｂの２個で構成されている。In the magnetostrictive torque sensor having the above-mentioned structure, the yoke 7 has a so-called split structure as shown in FIG. 5 before being incorporated in the magnetostrictive torque sensor (note that FIG. 5A).
Is a front view, and FIG. 5 (b) is a side view thereof), and two yokes 7a and 7b.
【０００５】このヨーク７ａ、７ｂを磁歪式トルクセン
サに組み込む際には、先ず、ヨーク７ａ、７ｂの溝７
ａ’、７ｂ’に上述のコイル５を収納し、溝７ａ”、７
ｂ”に上述のコイル６を収納する。そして、２つ割り状
態のヨーク７ａ、７ｂ間に回転軸１を通し、ヨーク７
ａ、７ｂを接合し、例えば不図示のバンドを巻装して両
ヨーク７ａ、７ｂを保定する。その後、ヨーク７ａ、７
ｂは保持部材９によってハウジング４に固定され、その
際、絶縁部材８によりハウジング４とヨーク７ａ、及び
ハウジング４とヨーク７ｂは絶縁される。When incorporating the yokes 7a and 7b into the magnetostrictive torque sensor, first, the grooves 7 of the yokes 7a and 7b are formed.
The coil 5 described above is housed in a ', 7b', and the grooves 7a ", 7 '
The above-mentioned coil 6 is housed in b ″. Then, the rotary shaft 1 is passed between the yokes 7a and 7b in the two-split state, and
The yokes 7a and 7b are retained by joining a and 7b and winding a band (not shown), for example. Then, the yoke 7a, 7
b is fixed to the housing 4 by the holding member 9, and the insulating member 8 insulates the housing 4 from the yoke 7a and the housing 4 from the yoke 7b.
【０００６】この様にして作成された磁歪式トルクセン
サの回転軸１に、一定方向のトルクがかかると、磁歪膜
２及び３の磁気抵抗が変化し、コイル５、６により形成
される磁界も変化し、例えば磁気異方性が互いに対称と
なるように配設された磁歪膜２、３では、その変化も倍
増して検出され、コイル５、６の出力電圧の変化からト
ルクを検出する。When a torque in a fixed direction is applied to the rotary shaft 1 of the magnetostrictive torque sensor thus manufactured, the magnetic resistance of the magnetostrictive films 2 and 3 changes, and the magnetic field formed by the coils 5 and 6 also changes. In the magnetostrictive films 2 and 3 which are changed and are arranged so that the magnetic anisotropies are symmetrical to each other, the change is also doubled and detected, and the torque is detected from the change in the output voltage of the coils 5 and 6.
【０００７】[0007]
【発明が解決しようとする課題】上述の構成の磁歪式ト
ルクセンサでは、コイル５及び６により形成される磁界
の発生に伴って、回転軸１の周方向にうず電流が発生
し、このうず電流はヨーク７（７ａ、７ｂ）内を流れ
る。しかし、上述の磁歪式トルクセンサでは、前述の様
にヨーク７は２つ割りのヨーク７ａ、７ｂを接合して組
み立てられているのでヨーク７ａ、７ｂ間に接合部を有
する。この接合部は、ヨーク７ａ、７ｂがバンドで抑え
られている為、通常密接している。しかし、ヨーク７
ａ、７ｂはパーマロイ等で構成され、所定の熱膨張率を
有し、温度変化によりその密接度が変わる。この様に温
度変化により、接合部の密接度が変わると接触抵抗（電
気抵抗値）も変化し、このヨーク７ａ、７ｂ内を流れる
うず電流が影響を受ける。In the magnetostrictive torque sensor having the above structure, an eddy current is generated in the circumferential direction of the rotary shaft 1 with the generation of the magnetic field formed by the coils 5 and 6, and this eddy current is generated. Flows in the yoke 7 (7a, 7b). However, in the above-described magnetostrictive torque sensor, the yoke 7 is assembled by joining the two split yokes 7a and 7b as described above, and thus has a joint portion between the yokes 7a and 7b. Since the yokes 7a and 7b are restrained by the band, this joint portion is normally in close contact. But York 7
Each of a and 7b is made of permalloy or the like, has a predetermined coefficient of thermal expansion, and its closeness changes depending on the temperature change. As described above, when the degree of contact of the joint changes due to the temperature change, the contact resistance (electrical resistance value) also changes, and the eddy currents flowing in the yokes 7a and 7b are affected.
【０００８】例えば、温度変化によりヨーク７ａ、７ｂ
接合部の密接度が低下すると、接合部の接触抵抗は増加
し、ヨーク７ａ、７ｂに流れるうず電流は減る。一方、
温度変化により、ヨーク７ａ、７ｂ接合部の密接度が増
すと、接合部の接触抵抗は低下し、ヨーク７ａ、７ｂに
流れるうず電流は増加する。したがって、温度変化によ
り、ヨーク７ａ、７ｂ内を流れるうず電流は変化し、こ
のうず電流の変化によりコイル５及び６に発生する磁界
は影響を受け、正確なトルクの測定ができない。例え
ば、常温において零点設定しても、後の温度変化により
ドリフトし、基準値がずれてしまう。For example, the yokes 7a and 7b are changed due to temperature change.
When the closeness of the joint decreases, the contact resistance of the joint increases and the eddy current flowing through the yokes 7a and 7b decreases. on the other hand,
When the closeness of the joints of the yokes 7a and 7b increases due to the temperature change, the contact resistance of the joints decreases and the eddy current flowing through the yokes 7a and 7b increases. Therefore, the eddy current flowing in the yokes 7a and 7b changes due to the temperature change, and the magnetic field generated in the coils 5 and 6 is affected by the change in the eddy current, and accurate torque measurement cannot be performed. For example, even if the zero point is set at room temperature, it drifts due to the subsequent temperature change and the reference value shifts.
【０００９】また、従来のヨーク７は、上述の様に２つ
割りのヨーク７ａ、７ｂで構成されている為、バンドで
保持しても上述の温度変化や、振動等によりその接合部
が位置ずれを生じる。すなわち、従来の磁歪式トルクセ
ンサでは、接合部が接着剤等で固定されていない為、位
置ずれが生じた場合接合部の接触抵抗が増し、うず電流
が変化する原因となる。したがって、従来の磁歪式トル
クセンサではこの点からも、予め設定した基準値はず
れ、正確なトルク測定ができない。Further, since the conventional yoke 7 is composed of the two split yokes 7a and 7b as described above, even if it is held by the band, the joint portion is located due to the above-mentioned temperature change or vibration. A gap occurs. That is, in the conventional magnetostrictive torque sensor, since the joint portion is not fixed with an adhesive or the like, when the position shift occurs, the contact resistance of the joint portion increases, which causes the eddy current to change. Therefore, the conventional magnetostrictive torque sensor also deviates from the preset reference value from this point, and accurate torque measurement cannot be performed.
【００１０】本発明は上記問題に鑑み、温度変化や振動
による接合部のずれを防止し、うず電流の影響をなく
し、正確なトルク測定を可能とする磁歪式トルクセンサ
を提供することを目的とする。In view of the above problems, it is an object of the present invention to provide a magnetostrictive torque sensor capable of preventing displacement of a joint portion due to temperature change or vibration, eliminating the influence of eddy current, and enabling accurate torque measurement. To do.
【００１１】[0011]
【課題を解決するための手段】本発明の１つの構成は、
２個の相似形磁性部材を接合し該接合部に絶縁部材を介
装した円筒状磁性部材と、該円筒状磁性部材の内周に環
状に形成された凹部に配設されたコイルと、前記円筒状
磁性部材の内周部と所定の隙間を有して回転自在に配設
された回転軸と、該回転軸の周面に形成され該回転軸に
負荷されるトルクを透磁率の変化として検出し、前記コ
イルの作成する磁束を変化させる磁歪センサと、で構成
する磁歪式トルクセンサである。One structure of the present invention is as follows.
A cylindrical magnetic member in which two similar magnetic members are joined and an insulating member is interposed in the joined portion; a coil disposed in a recess formed in an inner periphery of the cylindrical magnetic member in an annular shape; A rotary shaft rotatably arranged with a predetermined gap from the inner peripheral portion of the cylindrical magnetic member, and a torque formed on the peripheral surface of the rotary shaft and applied to the rotary shaft, as a change in magnetic permeability. A magnetostrictive sensor for detecting and changing a magnetic flux created by the coil.
【００１２】また、前記構成の中で、前記回転軸には、
例えば磁気異方性の異なる２つの磁歪膜が配設され、２
つの磁歪膜の磁気異方性は例えば対称である。また、前
記構成の中で、前記円筒状磁性部材は、２個の相似形磁
性部材が接着剤で接合されて構成されている。Further, in the above construction, the rotary shaft is
For example, two magnetostrictive films having different magnetic anisotropies are arranged,
The magnetic anisotropy of the two magnetostrictive films is symmetrical, for example. Further, in the above configuration, the cylindrical magnetic member is configured by joining two similar magnetic members with an adhesive.
【００１３】さらに、本発明の他の構成は、トルクが負
荷される回転軸と、該回転軸に形成され該回転軸に負荷
されるトルクの変化を検出する磁歪センサと、該磁歪セ
ンサの近傍に形成され該磁歪センサに磁束を供給するコ
イルと、２個の相似形磁性部材に絶縁部材を介装して円
筒状に形成し、前記磁歪センサと共に前記コイルが作成
する磁束に基づく磁気回路を形成する円筒状磁性部材と
で構成する磁歪式トルクセンサである。Further, according to another structure of the present invention, a rotating shaft to which a torque is applied, a magnetostrictive sensor formed on the rotating shaft for detecting a change in the torque applied to the rotating shaft, and the vicinity of the magnetostrictive sensor. And a coil for supplying magnetic flux to the magnetostrictive sensor, and a magnetic circuit based on the magnetic flux created by the coil together with the magnetostrictive sensor, which is formed into a cylindrical shape by interposing an insulating member between two similar magnetic members. It is a magnetostrictive torque sensor configured with a formed cylindrical magnetic member.
【００１４】また、前記構成の中で、前記回転軸には、
例えば磁気異方性の異なる２つの磁歪膜が配設され、２
つの磁歪膜の磁気異方性は例えば対称である。また、前
記構成の中で、前記円筒状磁性部材は、２個の相似形磁
性部材が接着剤で接合されて構成されている。In the above construction, the rotary shaft is
For example, two magnetostrictive films having different magnetic anisotropies are arranged,
The magnetic anisotropy of the two magnetostrictive films is symmetrical, for example. Further, in the above configuration, the cylindrical magnetic member is configured by joining two similar magnetic members with an adhesive.
【００１５】[0015]
【作用】磁歪式トルクセンサとして、２つ割りの磁性部
材を接合して使用する場合、温度に基づく接触抵抗の変
化からうず電流の影響を受けトルクの測定が正確に行え
なかったが、本発明は２つ割りの磁性部材を接合する
際、その接合部にフィルム等の絶縁部材を介装し、うず
電流の流れを遮断するので、回転軸に取り付けられた磁
歪膜の透磁率の変化をうず電流に影響されることなく正
確に測定することができ、しかも２個の磁性部材は上述
の絶縁部材を介装すると共に、接着剤等で接着固定する
ので、温度変化や振動等により位置ずれを生じることも
ない。In the case of using the magnetostrictive torque sensor by joining the two magnetic members, the torque cannot be measured accurately due to the influence of the eddy current due to the change of the contact resistance based on the temperature. When joining two halves of a magnetic member, an insulating member such as a film is interposed at the joint to block the flow of eddy currents, so that the change in the magnetic permeability of the magnetostrictive film attached to the rotating shaft can be prevented. Accurate measurement is possible without being affected by electric current. Moreover, since the two magnetic members have the above-mentioned insulating member interposed therebetween and are fixedly adhered with an adhesive or the like, the positional deviation due to temperature change or vibration is caused. It never happens.
【００１６】また、トルクが加わる回転軸には、例えば
磁気異方性の異なる２つの磁歪膜を配設することによ
り、互いに対称の応力、例えば圧縮と伸張という応力を
検出でき、より正確なトルク測定を行うことが可能とな
る。Further, by disposing, for example, two magnetostrictive films having different magnetic anisotropies on the rotating shaft to which torque is applied, stresses symmetrical to each other, for example, stresses of compression and expansion can be detected, and more accurate torque can be obtained. It becomes possible to perform the measurement.
【００１７】[0017]
【実施例】以下、本発明の一実施例について、図面を参
照しながら説明する。図１は一実施例の磁歪式トルクセ
ンサの断面図である。同図において、本実施例の磁歪式
トルクセンサ１０は、トルクがかかる回転軸１１と、ハ
ウジング１２に収納された円筒状の磁性部材（ヨーク）
１３、コイル１４、基板１５、絶縁部材１６、等で構成
されている。回転軸１１には、その一端に、モータ等の
回転軸１１の軸が機構的に結合され、又は回転体１１が
モータ等の回転体の回転軸そのもので構成されている。
また、回転軸１１には磁歪膜１１ａ、１１ｂが配設され
ている。この磁歪膜１１ａ、１１ｂはトルクがかかると
（応力が加えられると）、透磁率が変化する素子であ
り、磁歪膜１１ａと１１ｂには膜そのものに溝１１
ａ’、１１ｂ’が形成されている。この溝１１ａ’、１
１ｂ’は互いに直交する方向に形成され、互いに対称の
応力、例えば圧縮と伸張という応力を検出でき、且つ後
述する測定回路により磁歪膜１１ａ、１１ｂの検出出力
を差動増幅しトルクの確実な測定を行う構成である。An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a magnetostrictive torque sensor according to an embodiment. Referring to FIG. 1, a magnetostrictive torque sensor 10 according to this embodiment includes a rotating shaft 11 to which torque is applied and a cylindrical magnetic member (yoke) housed in a housing 12.
13, the coil 14, the substrate 15, the insulating member 16, and the like. The rotary shaft 11 is mechanically coupled to one end thereof with the shaft of the rotary shaft 11 such as a motor, or the rotary body 11 is constituted by the rotary shaft itself of the rotary body such as a motor.
Magnetostrictive films 11a and 11b are arranged on the rotating shaft 11. The magnetostrictive films 11a and 11b are elements whose magnetic permeability changes when torque is applied (when stress is applied), and the magnetostrictive films 11a and 11b have grooves 11 in the films themselves.
a'and 11b 'are formed. This groove 11a ', 1
1b 'are formed in directions orthogonal to each other, and stresses symmetrical to each other, for example, stresses of compression and extension, can be detected, and the detection output of the magnetostrictive films 11a and 11b is differentially amplified by a measurement circuit described later to reliably measure torque. It is a configuration for performing.
【００１８】尚、回転軸１１はハウジング１２に固定さ
れた軸受け２０により回転自在に構成されている。ま
た、回転軸１１の直径は、例えばＬ’で構成されてい
る。一方、磁性部材１３はコイル１４から発生する磁束
の磁路を形成すると共に、この磁束がハウジング１２
（及びハウジング１２外）へ漏出することを防止する部
材である。図２は、この磁性部材１３の構成を示す図で
あり、同図（ａ）は磁性部材１３の正面図を示し、同図
（ｂ）はその側面図を示す。同図に示す様に、磁性部材
１３は２つ割りの磁性部材１３ａ、１３ｂで構成され、
磁性部材１３ａ、１３ｂは互いに相似形である。また、
磁性部材１３の内径Ｌは、上述の回転軸１１の外径Ｌ’
（図１）より数ｍｍ（例えば、２〜４ｍｍ）広く形成さ
れ、この磁性部材１３を磁歪式トルクセンサ１０に取り
付けた状態で、回転軸１１と磁性部材１３の間隔が、例
えば１〜２ｍｍとなる様に構成されている。The rotary shaft 11 is rotatably constituted by a bearing 20 fixed to the housing 12. The diameter of the rotating shaft 11 is, for example, L '. On the other hand, the magnetic member 13 forms a magnetic path of the magnetic flux generated from the coil 14, and the magnetic flux is generated by the housing 12.
(And outside the housing 12) is a member that prevents leakage. 2A and 2B are views showing the configuration of the magnetic member 13, where FIG. 2A shows a front view of the magnetic member 13 and FIG. 2B shows a side view thereof. As shown in the figure, the magnetic member 13 is composed of two split magnetic members 13a and 13b,
The magnetic members 13a and 13b are similar to each other. Also,
The inner diameter L of the magnetic member 13 is the outer diameter L ′ of the rotating shaft 11 described above.
It is formed several mm (for example, 2 to 4 mm) wider than (FIG. 1), and when the magnetic member 13 is attached to the magnetostrictive torque sensor 10, the gap between the rotary shaft 11 and the magnetic member 13 is, for example, 1 to 2 mm. It is configured to be.
【００１９】また、磁性部材１３ａ、１３ｂの接合部Ｆ
には、絶縁部材２１が介装されている。この絶縁部材２
１は円筒状の磁性部材１３に発生するうず電流を遮断す
る部材であり、フィルム等の薄い材料で構成されてい
る。尚、同図では説明上、ある程度の厚さを有して示し
ている。また、絶縁部材２１は絶縁性を有していれば良
く、誘電性を有する材料で構成しても良い。The joint F of the magnetic members 13a and 13b
An insulating member 21 is interposed between the two. This insulating member 2
Reference numeral 1 denotes a member that blocks an eddy current generated in the cylindrical magnetic member 13, and is made of a thin material such as a film. It should be noted that, in the same figure, for the sake of explanation, it is shown as having a certain thickness. Further, the insulating member 21 need only have an insulating property, and may be made of a material having a dielectric property.
【００２０】また、磁性部材１３ａと１３ｂの接合部Ｆ
には絶縁部材２１が介装されると共に、接着剤２２によ
り磁性部材１３ａと１３ｂは接続、固定されている。こ
の接着剤２２も絶縁性の材料で構成されている。したが
って、実質的には磁性部材１３ａ，１３ｂ間には絶縁部
材２１と、接着剤２２が介装されることになり、この厚
さを考慮して磁性部材１３ａ，１３ｂの周径（内径Ｌ）
は絶縁部材２１を接着剤２２と共に介装した時の層厚
分、狭い周径で構成されている。Further, the joint F between the magnetic members 13a and 13b
An insulating member 21 is interposed between the magnetic members 13a and 13b, and the magnetic members 13a and 13b are connected and fixed by an adhesive 22. This adhesive 22 is also made of an insulating material. Therefore, the insulating member 21 and the adhesive 22 are substantially interposed between the magnetic members 13a and 13b, and in consideration of this thickness, the circumferential diameter (inner diameter L) of the magnetic members 13a and 13b.
Has a narrow peripheral diameter corresponding to the layer thickness when the insulating member 21 is interposed with the adhesive 22.
【００２１】一方、上述の磁性部材１３の凹部にはコイ
ル１４が配設され（図１参照）、コイル１４はコイルボ
ビン１７に巻装されている。このコイルボビン１７には
１次コイルと２次コイルが巻装され、１次コイルは励磁
用の磁束形成を行い、２次コイルは１次コイルで形成し
た磁束が磁歪膜１１ａ、１１ｂにより影響を受け、変化
した磁束の検出用コイルを構成する。尚、コイルボビン
１７に巻装されるコイル１４の出力は、不図示のリード
線により基板１５に接続される。尚、図２（ａ）に示す
１７’は磁性部材１３の凹部に配設されるコイルボビン
１７（コイル１４）の位置を示す。また、凹部は磁性部
材１３の内周面に沿って、所定の幅で形成され、コイル
ボビン１７はこの凹部に沿って配設されている。On the other hand, a coil 14 is provided in the recess of the above-mentioned magnetic member 13 (see FIG. 1), and the coil 14 is wound around a coil bobbin 17. A primary coil and a secondary coil are wound around the coil bobbin 17, the primary coil forms a magnetic flux for excitation, and the secondary coil has a magnetic flux formed by the primary coil affected by the magnetostrictive films 11a and 11b. , A coil for detecting the changed magnetic flux. The output of the coil 14 wound around the coil bobbin 17 is connected to the substrate 15 by a lead wire (not shown). In addition, 17 'shown in FIG. 2A shows the position of the coil bobbin 17 (coil 14) disposed in the recess of the magnetic member 13. The recess is formed with a predetermined width along the inner peripheral surface of the magnetic member 13, and the coil bobbin 17 is disposed along the recess.
【００２２】また、リード線が接続される基板１５に
は、２次コイルで検出した信号から回転軸１１にかかる
トルクを測定する処理回路が設けられている。図３はこ
の処理回路、及び１次コイル、２次コイルの接続構成を
示す図である。尚、同図において基板１５内の回路は点
線で囲った範囲であり、２個のコイルボビン１７に配設
された１次コイル（図３に１４ｂで示す）は直列に接続
され、交流電源２３から交流電流が供給され、励磁用磁
束を作成する。また、２次コイル（図３に１４ｃで示
す）は２個のコイルボビンについてそれぞれ独立して処
理回路２４に接続され、磁歪膜１１ａ、１１ｂに影響さ
れた磁界の変化を処理回路２４へ出力する。The substrate 15 to which the lead wire is connected is provided with a processing circuit for measuring the torque applied to the rotary shaft 11 from the signal detected by the secondary coil. FIG. 3 is a diagram showing the connection configuration of this processing circuit, the primary coil, and the secondary coil. In the figure, the circuit inside the substrate 15 is a range surrounded by a dotted line, and the primary coils (indicated by 14b in FIG. 3) arranged in the two coil bobbins 17 are connected in series and are connected from the AC power source 23. An alternating current is supplied to create a magnetic flux for excitation. The secondary coil (indicated by 14c in FIG. 3) is independently connected to the processing circuit 24 for each of the two coil bobbins, and outputs the change in the magnetic field affected by the magnetostrictive films 11a and 11b to the processing circuit 24.
【００２３】以上の構成の磁歪式トルクセンサ１０にお
いて、回転軸１１にかかるトルクを測定する時の処理を
説明する。先ず、トルクの測定を希望する回転体の軸を
磁歪式トルクセンサ１０の回転軸１１に連結する。尚、
トルクを測定しようとする回転体の軸そのものが、回転
軸１１であっても良い。この状態で前述の交流電源２３
から１次コイル１４ｂに交流電流を供給し、１次コイル
１４ｂを励磁して上述の磁歪膜１１ａ、１１ｂを通過す
る磁界（励磁用磁界）を作成する。この状態で回転軸１
１にトルクがかかっていなければ（所謂無負荷であれ
ば）、磁歪膜１１ａ、１１ｂでの透磁率に変化はなく、
又は応力が生じたとしても磁歪膜１１ａ、１１ｂに生じ
る応力は対称的で等しいので変化した透磁率は処理回路
２４にて出力電圧の段階で互いに打ち消し合う。したが
って、２次コイル１４ｃで検出する磁界に基づく２次コ
イル１４ｃの出力電圧は実質的に変化せず、この時、処
理回路２４は回転軸１１にトルクがかかっていないと判
断する。In the magnetostrictive torque sensor 10 having the above structure, a process for measuring the torque applied to the rotary shaft 11 will be described. First, the shaft of the rotating body whose torque is desired to be measured is connected to the rotating shaft 11 of the magnetostrictive torque sensor 10. still,
The rotary shaft 11 itself may be the shaft of the rotating body for measuring the torque. In this state, the above-mentioned AC power source 23
To supply an alternating current to the primary coil 14b to excite the primary coil 14b to create a magnetic field (excitation magnetic field) that passes through the magnetostrictive films 11a and 11b. Rotating shaft 1 in this state
If no torque is applied to 1 (so-called no load), there is no change in the magnetic permeability of the magnetostrictive films 11a and 11b,
Alternatively, even if a stress is generated, the stresses generated in the magnetostrictive films 11a and 11b are symmetrical and equal, and thus the changed magnetic permeability cancels each other out at the stage of the output voltage in the processing circuit 24. Therefore, the output voltage of the secondary coil 14c based on the magnetic field detected by the secondary coil 14c does not substantially change, and at this time, the processing circuit 24 determines that the torque is not applied to the rotating shaft 11.
【００２４】一方、回転軸１１に一定方向のトルクがか
かると、磁気異方性により一方の磁歪膜（例えば磁歪膜
１１ａ）の透磁率は増大し、他方の磁歪膜（例えば磁歪
膜１１ｂ）の透磁率は低下する。この為、磁歪膜１１
ａ、１１ｂを通過する磁界に変化が生じ、例えば２次コ
イル１４ｃの両電圧を比較し差動出力する処理回路２４
の出力は大きくなり、確実なトルクの測定を行うことが
できる。On the other hand, when torque is applied to the rotating shaft 11 in a fixed direction, the magnetic permeability of one magnetostrictive film (for example, the magnetostrictive film 11a) increases due to magnetic anisotropy, and that of the other magnetostrictive film (for example, the magnetostrictive film 11b). The magnetic permeability decreases. Therefore, the magnetostrictive film 11
The magnetic field passing through a and 11b is changed, and for example, the processing circuit 24 that compares both voltages of the secondary coil 14c and outputs differentially.
Output is increased, and reliable torque measurement can be performed.
【００２５】また、上述のトルク測定の際、１次コイル
１４ｂにより形成される磁束によって、磁性部材１３に
はうず電流が発生するはずである。この時発生するはず
のうず電流は、上述の磁界を切る方向に形成される為、
円筒状の磁性部材１３の周方向に形成される。しかし、
本実施例の磁歪式トルクセンサ１０は、２つ割り構成の
磁性部材１３ａと１３ｂを接合して作成するものである
が、その接合部に絶縁部材２１が介装されているので、
磁性部材１３内を流れるうず電流を遮断することができ
る。すなわち、磁性部材１３は絶縁部材２１で電気的に
遮断されている為、うず電流は流れず、従って従来の様
に温度変化により接合部の密接度が変化し、うず電流量
が変わるという問題は発生しない。したがって、回転体
１１にかかるトルクを測定する際、うず電流に影響され
ることなく回転体１１にかかるトルクを正確に測定する
ことができる。In the above torque measurement, an eddy current should be generated in the magnetic member 13 due to the magnetic flux formed by the primary coil 14b. The eddy current that should be generated at this time is formed in the direction of cutting the above-mentioned magnetic field,
It is formed in the circumferential direction of the cylindrical magnetic member 13. But,
The magnetostrictive torque sensor 10 of the present embodiment is made by joining the magnetic members 13a and 13b having a two-piece structure, but since the insulating member 21 is interposed at the joint,
The eddy current flowing in the magnetic member 13 can be cut off. That is, since the magnetic member 13 is electrically cut off by the insulating member 21, the eddy current does not flow. Therefore, the problem that the closeness of the joint changes due to the temperature change and the eddy current amount changes unlike the conventional case. Does not occur. Therefore, when measuring the torque applied to the rotor 11, the torque applied to the rotor 11 can be accurately measured without being affected by the eddy current.
【００２６】但し、うず電流が全く零になるものではな
く、例えば絶縁部材２１で遮蔽された回路、すなわち、
それぞれの磁性部材１３ａ、１３ｂ内をうず電流が流れ
ることは考えられる。しかし、この時流れるうず電流
は、それぞれの磁性部材１３ａ、１３ｂ内を還流する電
流であり、従来の様に接合部を流れる電流ではない為、
温度変化によりうず電流量が影響を受けることはない。However, the eddy current does not become completely zero, for example, a circuit shielded by the insulating member 21, that is,
It is conceivable that an eddy current flows in each of the magnetic members 13a and 13b. However, the eddy current that flows at this time is a current that flows back in the respective magnetic members 13a and 13b, and is not a current that flows through the junction unlike in the conventional case.
The eddy current amount is not affected by the temperature change.
【００２７】また、本実施例では磁性部材１３ａと１３
ｂを接着剤で接合することにより、温度変化はもとよ
り、振動等に対しても磁性部材１３ａ、１３ｂの接合部
がずれることがない。In this embodiment, the magnetic members 13a and 13a
By joining b with an adhesive, the joining portion of the magnetic members 13a and 13b does not shift not only when the temperature changes but also when vibration or the like occurs.
【００２８】尚、本実施例では磁性部材１３ａ、１３ｂ
間に絶縁部材２１を介装したこと、及びその接合を接着
剤を用いて行うことから、従来に比べて、基準値に対す
る温度ドリフトの低減効果は大きく、例えば従来２００
％／ＦＳ（フルスケール）であったものが、１０％／Ｆ
Ｓ（フルスケール）まで低下した。In this embodiment, the magnetic members 13a and 13b are used.
Since the insulating member 21 is interposed between them and the bonding is performed by using an adhesive, the effect of reducing the temperature drift with respect to the reference value is large as compared with the conventional case.
% / FS (full scale) was 10% / F
It decreased to S (full scale).
【００２９】また、上述の実施例では磁歪膜は１１ａ、
１１ｂとして２枚で構成したが、必ずしも２枚で構成す
る必要はない。検出感度は落ちるが、１枚で構成しても
良い。In the above embodiment, the magnetostrictive film is 11a,
Although 11b is composed of two sheets, it is not always required to be composed of two sheets. Although the detection sensitivity is reduced, one sheet may be used.
【００３０】さらに、磁性部材１３ａ、１３ｂはパーマ
ロイに限らず、磁性材料であり且つうず電流が流れる導
電性材料で構成されるものであれば磁性部材として使用
することができる。Further, the magnetic members 13a and 13b are not limited to permalloy, but may be magnetic members as long as they are magnetic materials and are made of a conductive material through which an eddy current flows.
【００３１】[0031]
【発明の効果】以上詳細に説明したように、本発明によ
れば２つ割り構成の磁性部材間に絶縁部材を介装するの
で、うず電流が殆ど流れず、温度ドリフトをなくし、回
転軸にかかるトルクを正確に測定することができる。As described above in detail, according to the present invention, since the insulating member is interposed between the magnetic members having the two-divided structure, the eddy current hardly flows, the temperature drift is eliminated, and the rotating shaft is not moved. Such torque can be measured accurately.
【００３２】また、磁性部材間にフィルム等の絶縁部材
を介装し、接着するという極めて簡単な構成であるので
容易に実施でき、且つトルクの正確な測定という大きな
効果を得ることができるものである。Further, since an insulating member such as a film is interposed between the magnetic members and the members are adhered to each other, the structure can be easily implemented and a great effect of accurate measurement of torque can be obtained. is there.
【図１】一実施例の磁歪式トルクセンサの構成図であ
る。FIG. 1 is a configuration diagram of a magnetostrictive torque sensor according to an embodiment.
【図２】（ａ）は、一実施例の磁歪式トルクセンサに使
用される磁性部材の正面図である。（ｂ）は、一実施例
の磁歪式トルクセンサに使用される磁性部材の側面図で
ある。FIG. 2A is a front view of a magnetic member used in the magnetostrictive torque sensor according to the embodiment. (B) is a side view of the magnetic member used for the magnetostrictive torque sensor of one Example.
【図３】処理回路、及び１次コイル、２次コイルの接続
構成を説明する図である。FIG. 3 is a diagram illustrating a connection configuration of a processing circuit, a primary coil, and a secondary coil.
【図４】従来例の磁歪式トルクセンサの構成図である。FIG. 4 is a configuration diagram of a conventional magnetostrictive torque sensor.
【図５】２つ割りの磁性部材の構成を示す図である。FIG. 5 is a diagram showing a configuration of a magnetic member divided into two parts.
１０ 磁歪式トルクセンサ １１ 回転軸 １１ａ、１１ｂ 磁歪膜 １２ ハウジング １３ 磁性部材 １４ コイル １４ｂ １次コイル １４ｃ ２次コイル １５ 基板 １７ コイルボビン ２０ 軸受け ２１ 絶縁部材 ２２ 接着剤 ２３ 交流電源 ２４ 処理回路 Ｆ 接合部 10 Magnetostrictive Torque Sensor 11 Rotating Shafts 11a, 11b Magnetostrictive Film 12 Housing 13 Magnetic Member 14 Coil 14b Primary Coil 14c Secondary Coil 15 Substrate 17 Coil Bobbin 20 Bearing 21 Insulation Member 22 Adhesive 23 AC Power Supply 24 Processing Circuit F Joint
───────────────────────────────────────────────────── フロントページの続き (72)発明者 大立 泰治 愛知県刈谷市豊田町２丁目１番地 株式会 社豊田自動織機製作所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taiji Odachi 2-chome Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corp.
Claims (4)
部に絶縁部材を介装した円筒状磁性部材と、 該円筒状磁性部材の内周に環状に形成された凹部に配設
されたコイルと、 前記円筒状磁性部材の内周部と所定の隙間を有して回転
自在に配設された回転軸と、 該回転軸の周面に形成され、該回転軸に負荷されるトル
クを透磁率の変化として検出し、前記コイルの作成する
磁束を変化させる磁歪センサと、を有することを特徴と
する磁歪式トルクセンサ。1. A cylindrical magnetic member having two similar magnetic members joined to each other, and an insulating member interposed between the joined magnetic members, and a cylindrical magnetic member having an annular recess formed on the inner circumference thereof. Coil, a rotating shaft rotatably disposed with a predetermined gap from the inner peripheral portion of the cylindrical magnetic member, and formed on the peripheral surface of the rotating shaft and loaded on the rotating shaft. A magnetostrictive sensor that detects torque as a change in magnetic permeability and changes the magnetic flux created by the coil.
化を検出する磁歪センサと、 該磁歪センサの近傍に形成され、該磁歪センサに磁束を
供給するコイルと、 ２個の相似形磁性部材の接合部に絶縁部材を介装して円
筒状に形成され、前記磁歪センサと共に前記コイルが作
成する磁束に基づく磁気回路を形成する磁性部材と、 を有することを特徴とする磁歪式トルクセンサ。2. A rotating shaft to which a torque is applied, a magnetostrictive sensor which is provided on the rotating shaft and detects a change in the torque applied to the rotating shaft, and a magnetostrictive sensor formed in the vicinity of the magnetostrictive sensor. A coil that supplies a magnetic flux to a magnetic field, and a magnetism that forms a magnetic circuit based on the magnetic flux created by the coil together with the magnetostrictive sensor, by forming an insulating member at the joint between two similar magnetic members. A magnetostrictive torque sensor comprising: a member;
つの磁歪センサが配設されていることを特徴とする請求
項１、又は２記載の磁歪式トルクセンサ。3. The rotation axis has two different magnetic anisotropies.
The magnetostrictive torque sensor according to claim 1, wherein two magnetostrictive sensors are provided.
性部材が接着剤で接合されて成ることを特徴とする請求
項１、又は２記載の磁歪式トルクセンサ。4. The magnetostrictive torque sensor according to claim 1, wherein the cylindrical magnetic member is formed by joining two similar magnetic members with an adhesive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25094994A JPH08114515A (en) | 1994-10-17 | 1994-10-17 | Magnetostriction type torque sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25094994A JPH08114515A (en) | 1994-10-17 | 1994-10-17 | Magnetostriction type torque sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08114515A true JPH08114515A (en) | 1996-05-07 |
Family
ID=17215410
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25094994A Withdrawn JPH08114515A (en) | 1994-10-17 | 1994-10-17 | Magnetostriction type torque sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08114515A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010119773A1 (en) * | 2009-04-17 | 2010-10-21 | 本田技研工業株式会社 | Magnetostrictive torque sensor and electrical power steering device |
| JP2010249734A (en) * | 2009-04-17 | 2010-11-04 | Honda Motor Co Ltd | Magnetostrictive torque sensor and electric power steering apparatus |
-
1994
- 1994-10-17 JP JP25094994A patent/JPH08114515A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010119773A1 (en) * | 2009-04-17 | 2010-10-21 | 本田技研工業株式会社 | Magnetostrictive torque sensor and electrical power steering device |
| JP2010249734A (en) * | 2009-04-17 | 2010-11-04 | Honda Motor Co Ltd | Magnetostrictive torque sensor and electric power steering apparatus |
| US8701503B2 (en) | 2009-04-17 | 2014-04-22 | Honda Motor Co., Ltd. | Magnetostrictive torque sensor and electrical power steering device |
| JP5638516B2 (en) * | 2009-04-17 | 2014-12-10 | 本田技研工業株式会社 | Magnetostrictive torque sensor and electric power steering apparatus |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20020115 |