JPH01112124A - Strain detector - Google Patents
Strain detectorInfo
- Publication number
- JPH01112124A JPH01112124A JP27116487A JP27116487A JPH01112124A JP H01112124 A JPH01112124 A JP H01112124A JP 27116487 A JP27116487 A JP 27116487A JP 27116487 A JP27116487 A JP 27116487A JP H01112124 A JPH01112124 A JP H01112124A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- adhesive
- magnetic layer
- passive shaft
- balls
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000853 adhesive Substances 0.000 claims abstract description 23
- 230000001070 adhesive effect Effects 0.000 claims abstract description 23
- 238000001514 detection method Methods 0.000 claims abstract description 13
- 230000035699 permeability Effects 0.000 claims abstract description 6
- 239000010410 layer Substances 0.000 abstract description 37
- 239000012790 adhesive layer Substances 0.000 abstract description 11
- 230000035945 sensitivity Effects 0.000 abstract description 10
- 230000035882 stress Effects 0.000 description 13
- 238000003756 stirring Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
- 229920006332 epoxy adhesive Polymers 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分計〕
この発明は例えば回転軸などの受動軸の歪を検出する歪
検出器に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Meter] The present invention relates to a strain detector for detecting strain in a passive shaft such as a rotating shaft.
第２図は従来の構成を示し、１は回転軸からなる受動軸
、２は受動軸１の中心軸、３，４は受動軸１を回転自在
に支持する軸受である。受動軸１の外周には高磁性材か
らなる第１及び第２の磁性層５，６が固着される。第１
の磁性層５は中心軸２に対して＋４５度方向に、第２の
磁性層６は中心軸２に対して一４５度方向にそれぞれ細
長く複数条形成されている。又、各磁性層５，６の外周
にはギャップを介して円筒状のコイルボビン７が受動軸
１と同軸状に配設される。コイルボビン７の外周には第
１及び第２の磁性層５，６に対応１ノで第１及び第２の
検出コイル８，９が巻装され、各検出コイル８，９は検
出回路１４に接続される。FIG. 2 shows a conventional configuration, in which 1 is a passive shaft consisting of a rotating shaft, 2 is a central axis of the passive shaft 1, and 3 and 4 are bearings that rotatably support the passive shaft 1. First and second magnetic layers 5 and 6 made of highly magnetic material are fixed to the outer periphery of the passive shaft 1. 1st
The magnetic layer 5 is formed in a plurality of strips in a direction of +45 degrees with respect to the central axis 2, and the second magnetic layer 6 is formed in a plurality of elongated strips in a direction of 145 degrees with respect to the central axis 2. Further, a cylindrical coil bobbin 7 is disposed coaxially with the passive shaft 1 on the outer periphery of each of the magnetic layers 5 and 6 with a gap therebetween. First and second detection coils 8 and 9 are wound around the outer periphery of the coil bobbin 7 in a manner corresponding to the first and second magnetic layers 5 and 6, and each detection coil 8 and 9 is connected to a detection circuit 14. be done.
又、１０，１１は検出コイル８，９の周囲に設けられた
高透磁率材からなる第１及び第２の磁気収束層である。Further, 10 and 11 are first and second magnetic convergence layers made of a high magnetic permeability material and provided around the detection coils 8 and 9.
磁性層５，６の受動軸１への取付に際しては、熱硬化性
−液エポキシ系接着剤を受動軸１に塗布し、磁性層５，
６を受動軸１にカシめな後、接着剤の加熱硬化を行って
いる。When attaching the magnetic layers 5, 6 to the passive shaft 1, apply a thermosetting liquid epoxy adhesive to the passive shaft 1, and then attach the magnetic layers 5, 6 to the passive shaft 1.
After crimping 6 onto the driven shaft 1, the adhesive is heated and hardened.
次に、動作について説明する。受動軸］に外部からトル
クが印加されると応力が受動軸１から接着剤を介して磁
性層５，６に伝帳し、磁性層５゜６の一方に引張力が発
生するとともに他方に圧縮力が発生し、歪が生じる。こ
の歪が生じると磁性層５，６の透磁率が変化し、引張力
による場合と圧縮力による場合では透磁率が逆方向に変
化する。Next, the operation will be explained. When torque is applied from the outside to the passive shaft 1, stress is transferred from the passive shaft 1 to the magnetic layers 5 and 6 through the adhesive, creating a tensile force in one of the magnetic layers 5 and 6, and compression in the other. Force is generated and distortion occurs. When this strain occurs, the magnetic permeability of the magnetic layers 5 and 6 changes, and the magnetic permeability changes in opposite directions depending on whether the tensile force is applied or the compressive force is applied.
検出コイル８，９は透磁率の変化を磁気的インピーダン
スの変化として検出し、検出口＠ｉａは各検出コイル８
，９の出力を入力され、受動軸１の歪量に応じた検出電
圧■を出力する。The detection coils 8 and 9 detect changes in magnetic permeability as changes in magnetic impedance, and the detection ports @ia are connected to each detection coil 8.
, 9, and outputs a detection voltage (■) corresponding to the amount of distortion of the passive shaft 1.
しかしながら、上記した従来の歪検出器においては、磁
性層５，６を受動軸１に接着するための接着剤の厚さに
バラツキが生じ易く、これによって特性にもバラツキが
生じた。即ち、受動軸１のヤング率Ｅ１、線膨張係数β
１、厚さｔｌ、接着層の剛性率Ｇ０、厚さｈ、磁性層５
，６の長さＬ１ヤング率Ｅ２、線膨張係数β２、厚さｔ
２とすると、受動軸１及び磁性層５，６のヤング率Ｅ、
、Ｅ２が接着層のヤング率より２桁程度大きいので、受
動軸１の表面に平行な圧ｍ／引張応力が接着層のせん断
変形で吸収され、受動軸１及び磁性層５，６には長さ方
向に−様な伸縮変形のみが生じ、曲げ変形が発生しない
と仮定する。受動軸１のＸ方向（長さ方向）の変形をＵ
ｏ、磁性層５，６の変形をｕ２とすると、接着層で受け
るせん断変形γは接着層の剛性率Ｇ０とせん断応力τに
対しての関係となる。又、ｔ２は２５μ程度、ｔ、は数
千μであるので、Ｅｌｔｌ〉〉Ｅ２ｔ２という仮定が成
り立ち、受動軸１の膜厚依存性は消え、受動軸１から接
着層を介して磁性層５，６に伝帳される応力で与えられ
る。第３図は接着層の厚さｈと応力伝帳比との関係を磁
性層５，６の長さしをパラメータとして示したものであ
り、接着層の厚さが変化すると応力伝帳比も変化する。However, in the conventional strain detector described above, the thickness of the adhesive for bonding the magnetic layers 5 and 6 to the passive shaft 1 tends to vary, which causes variations in characteristics. That is, Young's modulus E1 and linear expansion coefficient β of the passive shaft 1
1. Thickness tl, adhesive layer rigidity G0, thickness h, magnetic layer 5
, 6 length L1 Young's modulus E2, linear expansion coefficient β2, thickness t
2, the Young's modulus E of the passive shaft 1 and the magnetic layers 5 and 6 is
, E2 is about two orders of magnitude larger than the Young's modulus of the adhesive layer, the pressure m/tensile stress parallel to the surface of the passive shaft 1 is absorbed by shear deformation of the adhesive layer, and the passive shaft 1 and the magnetic layers 5 and 6 have a long It is assumed that only --like expansion/contraction deformation occurs in the horizontal direction and no bending deformation occurs. The deformation of the driven shaft 1 in the X direction (length direction) is expressed as U
o, and the deformation of the magnetic layers 5 and 6 is u2, then the shear deformation γ received by the adhesive layer has a relationship with the rigidity G0 of the adhesive layer and the shear stress τ. Also, since t2 is about 25μ and t is several thousand μ, the assumption that Eltl>>E2t2 holds true, and the film thickness dependence of the passive axis 1 disappears, and the magnetic layer 5, It is given by the stress transferred to 6. Figure 3 shows the relationship between the thickness h of the adhesive layer and the stress transfer ratio using the length of the magnetic layers 5 and 6 as a parameter, and as the thickness of the adhesive layer changes, the stress transfer ratio also changes. Change.
従って、特に磁性層５，６の変化を差動的に用いる場合
には磁性層５．６の応力に対するゲインにバラツキを生
じ、出力特性に非線形性が生じ、また残留熱応力などの
温度特性が悪化し、感度が低下した。Therefore, especially when using changes in the magnetic layers 5 and 6 differentially, variations occur in the gain with respect to stress in the magnetic layers 5 and 6, nonlinearity occurs in the output characteristics, and temperature characteristics such as residual thermal stress occur. worsened and sensitivity decreased.
この発明は上記のような問題点を解決するために成され
たものであり、出力特性、温度特性を改善し、感度を向
上することができる歪検出器を得ることを目的とする。This invention was made to solve the above-mentioned problems, and aims to provide a strain detector that can improve output characteristics, temperature characteristics, and improve sensitivity.
この発明に係る歪検出器は、磁性層を多数の同径の非磁
性ボールを混入した接着剤を介して受動軸に接着したも
のである。In the strain detector according to the present invention, a magnetic layer is bonded to a passive shaft via an adhesive containing a large number of non-magnetic balls of the same diameter.
この発明における接着剤は多数の同径の非磁性ボールを
混入されており、受動軸へ磁性層を押圧接着する際、こ
の非磁性ボールの存在により接着剤の厚さが非磁性ボー
ルの直径とほぼ等しくなり、均一となる。The adhesive in this invention is mixed with a large number of non-magnetic balls of the same diameter, and when press-bonding the magnetic layer to the passive shaft, the thickness of the adhesive becomes equal to the diameter of the non-magnetic balls due to the presence of these non-magnetic balls. They become almost equal and uniform.
以下、この発明の実施例を図面とともに説明する。第１
図はこの実施例による歪検出器の要部を断面で示したも
のであり、１２は多数の同径の非磁性ボール１３を混入
された接着剤である。非磁性ボール１３は例えば直径１
００μ以下のアルミナボールを用い、この非磁性ボール
１３はｆｆｌ ｌｉｔ 剤１２に対して重量％が５％の
割合で混入する。混入に際しては真空中で撹拌して脱泡
する。接着剤１２としては熱硬化性−液エポキシ系接着
剤を用いる。又、磁性層５，６としてはヤング率１６５
００ｋｇ ｆ ／ ｍｍのアモルファス磁性材を用いる
。磁性層５．６は受動軸１の外周に非磁性ボール１３を
混入した接着剤１２を介して接着固定する。Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows a cross section of the main part of the strain detector according to this embodiment, and 12 is an adhesive mixed with a large number of non-magnetic balls 13 having the same diameter. For example, the non-magnetic ball 13 has a diameter of 1
Alumina balls with a diameter of 00 μm or less are used, and the nonmagnetic balls 13 are mixed in the ffl lit agent 12 at a weight ratio of 5%. When mixing, defoaming is performed by stirring in a vacuum. As the adhesive 12, a thermosetting liquid epoxy adhesive is used. Furthermore, the magnetic layers 5 and 6 have a Young's modulus of 165.
00 kg f/mm amorphous magnetic material is used. The magnetic layer 5.6 is adhesively fixed to the outer periphery of the passive shaft 1 via an adhesive 12 containing non-magnetic balls 13.
上記構成において、非磁性ボール１３を用いたのは、磁
性ボールを用いると検出コイル８，９が発生する磁束の
通路となり、磁性層５，６の鎖交磁束数が減少し、感度
が低下するからである。又、ａｔ磁性層、６としてアモ
ルファス磁性材を用いたのは、磁歪定数が大きいことと
、硬度が大きいために変形が生じ難く、応力集中が生じ
難いためである。さらに、接着剤１２中への非磁性ボー
ル１３の混入を真空中で撹拌しながら行うのは、空気中
で撹拌を行うと泡が混入して硬くなり、撹拌が充分に行
えないためである。In the above configuration, the non-magnetic ball 13 is used because if a magnetic ball is used, it becomes a path for the magnetic flux generated by the detection coils 8 and 9, and the number of interlinked magnetic fluxes in the magnetic layers 5 and 6 decreases, resulting in a decrease in sensitivity. It is from. Further, the reason why an amorphous magnetic material is used for the at magnetic layer 6 is that it has a large magnetostriction constant and a large hardness, so that deformation and stress concentration are difficult to occur. Furthermore, the reason why the non-magnetic balls 13 are mixed into the adhesive 12 while stirring in a vacuum is because if stirring is performed in air, bubbles will be mixed in and the adhesive will become hard, making it impossible to perform sufficient stirring.
上記した歪検出器では、接着剤１２の厚さは非磁性ボー
ル１３の直径とほぼ等しくなり、その厚さは均一になり
、誤差は士数％以内に収まる。従って、第３図に示すよ
うに受動軸１から磁性層５゜６に伝帳する応力も均一に
なり、直線的な安定した出力特性が得られる。又、温度
特性にもバラツキはなくなり、磁性層５，６を差動的に
用いた場合には相殺される。さらに、接着剤１２中に非
磁性ボール１３を混入したことにより、接着層は全体と
して硬度が大きくなり、応力伝帳比が高くなって感度が
向上し、また接着層の線膨張係数βが小さくなり、受動
軸１や磁性層５，６とのβの差が小さくなり、熱応力が
減少する。又、感度の向上により効率も向上し、このた
め検出コイル８゜９の印加電流も小さ（て良く、回路部
分での発熱が減少し、経時変化が小さくなる。In the strain detector described above, the thickness of the adhesive 12 is approximately equal to the diameter of the non-magnetic ball 13, the thickness is uniform, and the error is within a few percent. Therefore, as shown in FIG. 3, the stress transmitted from the passive shaft 1 to the magnetic layer 5.6 becomes uniform, and stable linear output characteristics can be obtained. Further, there is no variation in temperature characteristics, and when the magnetic layers 5 and 6 are used differentially, they are canceled out. Furthermore, by mixing the non-magnetic balls 13 into the adhesive 12, the hardness of the adhesive layer as a whole increases, the stress transfer ratio increases, the sensitivity improves, and the linear expansion coefficient β of the adhesive layer decreases. Therefore, the difference in β between the passive shaft 1 and the magnetic layers 5 and 6 becomes smaller, and thermal stress is reduced. In addition, efficiency is also improved due to improved sensitivity, and therefore the current applied to the detection coil 8.9 is also small (only a small amount is required), heat generation in the circuit portion is reduced, and changes over time are reduced.
尚、非磁性ボール１３としては、ガラスピース、アクリ
ル／ポリエチレンビーズなどを用いても良い０
〔発明の効果〕
以上のようにこの発明によれば、磁性層を非磁性ボール
入りの接着剤を介して受動軸に固着しており、接着剤の
厚さは非磁性ボールの直径によって定まる均一なものと
なり、受動軸から接着剤を介して磁性層に伝帳する応力
も均一なものとなる。Incidentally, as the non-magnetic balls 13, glass pieces, acrylic/polyethylene beads, etc. may be used. [Effects of the Invention] As described above, according to the present invention, the magnetic layer is bonded via an adhesive containing non-magnetic balls. The thickness of the adhesive is determined by the diameter of the non-magnetic ball, and the stress transferred from the passive shaft to the magnetic layer through the adhesive is also uniform.
従って、出力特性及び温度特性も良好となり、感度が向
上する。又、接着剤は非磁性ボールの混入により感度が
高く線膨張係数が小さなものとなり、応力伝幅比が高く
残留熱応力が小さくなって感度が向上する。Therefore, output characteristics and temperature characteristics are also improved, and sensitivity is improved. In addition, the adhesive has high sensitivity and a small coefficient of linear expansion due to the inclusion of non-magnetic balls, and the stress propagation ratio is high and residual thermal stress is small, resulting in improved sensitivity.
第１図はこの発明による歪検出器の要部断面図、第２図
は従来の歪検出器の断面図、第３図は接着層の厚さと応
力伝帳比の関係図である。
１・・・受動軸、５，６ 磁性層、８，９・・検出コイ
ル、１２・接着剤、１３・・非磁性ボール。
尚、図中同一符号は同−又は相当部分を示す。FIG. 1 is a sectional view of a main part of a strain detector according to the present invention, FIG. 2 is a sectional view of a conventional strain detector, and FIG. 3 is a diagram showing the relationship between adhesive layer thickness and stress transfer ratio. DESCRIPTION OF SYMBOLS 1... Passive axis, 5, 6 Magnetic layer, 8, 9... Detection coil, 12... Adhesive, 13... Non-magnetic ball. Note that the same reference numerals in the figures indicate the same or corresponding parts.
Claims (1)
数の同径の非磁性ボールを混入された接着剤を介して固
着された高磁歪率の磁性層と、磁性層の周囲にギャップ
を隔てて配設され、磁性層の上記応力に応じた歪による
透磁率変化を検出する検出コイルを備えたことを特徴と
する歪検出器。(1) A passive shaft that is subjected to stress, a magnetic layer with a high magnetostriction fixed to the outer periphery of the passive shaft via an adhesive containing many non-magnetic balls of the same diameter, and a magnetic layer around the magnetic layer. A strain detector comprising a detection coil disposed across a gap to detect a change in magnetic permeability due to strain in a magnetic layer according to the stress.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27116487A JPH01112124A (en) | 1987-10-26 | 1987-10-26 | Strain detector |
| PCT/JP1988/000727 WO1989000770A1 (en) | 1987-07-21 | 1988-07-20 | Production of stress sensor |
| US07/346,112 US4954215A (en) | 1987-07-21 | 1988-07-20 | Method for manufacture stress detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27116487A JPH01112124A (en) | 1987-10-26 | 1987-10-26 | Strain detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01112124A true JPH01112124A (en) | 1989-04-28 |
Family
ID=17496231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27116487A Pending JPH01112124A (en) | 1987-07-21 | 1987-10-26 | Strain detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01112124A (en) |
-
1987
- 1987-10-26 JP JP27116487A patent/JPH01112124A/en active Pending
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