JPH0152911B2 - - Google Patents
Info
- Publication number
- JPH0152911B2 JPH0152911B2 JP56057149A JP5714981A JPH0152911B2 JP H0152911 B2 JPH0152911 B2 JP H0152911B2 JP 56057149 A JP56057149 A JP 56057149A JP 5714981 A JP5714981 A JP 5714981A JP H0152911 B2 JPH0152911 B2 JP H0152911B2
- Authority
- JP
- Japan
- Prior art keywords
- displacement
- electrostrictive element
- bolt
- electrostrictive
- equation
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、微小隙間や微小変位などの測定装置
に組込む好適な変位発生装置に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a displacement generating device suitable for being incorporated into a measuring device for measuring minute gaps, minute displacements, and the like.
一般に電歪素子などの変位発生素子は、微小変
位を発生させる手段として広く利用されている。
この変位発生素子で発生した変位量は駆動電圧を
測定して間接的に求めることが考えられるが、電
歪素子は、電圧と出力変位との関係がヒステリシ
ス特性を有している。このため、電歪素子の変位
量を間接的に求めた場合には、ヒステリシスが誤
差分として加算されることになり、測定精度が低
下する。
In general, displacement generating elements such as electrostrictive elements are widely used as means for generating minute displacements.
The amount of displacement generated by this displacement generating element may be indirectly determined by measuring the drive voltage, but the electrostrictive element has a hysteresis characteristic in the relationship between voltage and output displacement. For this reason, when the amount of displacement of the electrostrictive element is indirectly determined, hysteresis is added as an error amount, resulting in a decrease in measurement accuracy.
この問題を解決するために、ヒステリシス特性
を考慮して電歪素子の駆動電圧の波形を工夫した
方法が特公昭54−29359号公報に開示されている。
これによりヒステリシス特性による精度の改善が
みられるが、電圧と出力変位との関係を完全に直
線にすることが困難であるので、さらに高精度の
測定結果を必要とする場合には不十分である。 In order to solve this problem, Japanese Patent Publication No. 54-29359 discloses a method in which the waveform of the driving voltage of the electrostrictive element is devised in consideration of the hysteresis characteristics.
Although this improves accuracy due to hysteresis characteristics, it is difficult to make the relationship between voltage and output displacement completely linear, so it is insufficient when more accurate measurement results are required. .
また、圧電積層体の上部に突片を有する可動部
材を設け、圧電積層体の変位を差動トランスによ
つて検出する技術が特開昭55−120186号公報に開
示されている。この装置によれば、圧電積層体全
体の変位量を測定できるので、ヒステリシス特性
があつてもそれを補償した測定が可能となる。 Furthermore, Japanese Patent Laid-Open No. 120186/1986 discloses a technique in which a movable member having a protrusion is provided on the top of a piezoelectric laminate and the displacement of the piezoelectric laminate is detected by a differential transformer. According to this device, the amount of displacement of the entire piezoelectric laminate can be measured, so even if there is a hysteresis characteristic, it is possible to perform measurements that compensate for it.
ところで、この装置では、測定のために突片を
有する可動部材およびその突片の微動をとらえる
差動トランスなどが必要となり、構造が複雑とな
る。また、この突片やトランスなどがあるため
に、これを微小隙間や微小変形などの測定装置に
組込むことが困難であり、他の装置への組込の際
に実用上の問題を有する。そして、更に、この方
法では、突片が片持梁となつているので、変位発
生装置あるいはそれを組込む測定装置の機械的振
動により突片が上下に振れ、正確な測定を行う上
で問題を残している。
By the way, this device requires a movable member having a protruding piece and a differential transformer for capturing minute movements of the protruding piece for measurement, making the structure complicated. Furthermore, because of the protrusion and transformer, it is difficult to incorporate this into a device for measuring minute gaps or minute deformations, and there are practical problems when incorporating it into other devices. Furthermore, in this method, since the protrusion is in the form of a cantilever beam, the protrusion swings up and down due to mechanical vibration of the displacement generator or the measuring device incorporating it, which poses a problem in making accurate measurements. I'm leaving it behind.
本発明の目的は、簡単な構成で、測定装置など
へ組込むに適したものであつて、しかも正確な変
位測定を行うことのできる変位発生装置を提供す
ることである。 An object of the present invention is to provide a displacement generating device that has a simple configuration, is suitable for being incorporated into a measuring device, etc., and is capable of accurately measuring displacement.
本発明は、駆動電圧を印加することにより厚さ
方向に変位する変位発生素子と、この変位発生素
子の変位方向を拘束する拘束手段とを備えた変位
発生装置において、この拘束手段に変位発生素子
の変位を検出するためのひずみゲージを設けてい
る。
The present invention provides a displacement generating device that includes a displacement generating element that is displaced in the thickness direction by applying a driving voltage, and a restraining means that restrains the displacement direction of the displacement generating element. A strain gauge is provided to detect the displacement of the
電歪素子等の変位発生素子は、拘束手段によつ
てその変位方向が拘束される。この拘束によつ
て、変位発生素子に電圧を印加したときの変位に
抗する力が拘束手段に作用する。変位発生素子の
変位が大きければ大きいほど拘束手段に加わるひ
ずみは大きくなる。このため、拘束手段に設けら
れたひずみゲージは、変位発生素子の変位に対応
した出力を行うことになる。この場合、ひずみゲ
ージの出力は、変位発生素子全体の変位に対応し
たものとなる。このような手段によれば、変位素
子の補強のために従来より設けられている拘束手
段にひずみゲージを設けるだけで良いので、測定
のための構造が極めて簡単であり、特別な外付け
部品も必要としないので全体がコンパクトとな
り、測定装置に変位発生装置を組込むことも容易
にできる。また、全体が機械的に振動しても、拘
束手段が変位素子を拘束しており、その拘束手段
にひずみゲージを取付けているので、振動によつ
て測定誤差が生じるということはほとんどない。
The direction of displacement of a displacement generating element such as an electrostrictive element is restrained by a restraining means. Due to this restraint, a force that resists the displacement when voltage is applied to the displacement generating element acts on the restraint means. The greater the displacement of the displacement generating element, the greater the strain applied to the restraining means. Therefore, the strain gauge provided in the restraint means outputs an output corresponding to the displacement of the displacement generating element. In this case, the output of the strain gauge corresponds to the displacement of the entire displacement generating element. According to this method, it is only necessary to provide a strain gauge to the conventional restraint means for reinforcing the displacement element, so the structure for measurement is extremely simple and no special external parts are required. Since this is not necessary, the entire device becomes compact, and the displacement generator can be easily incorporated into the measuring device. Further, even if the entire device vibrates mechanically, the restraint means restrains the displacement element, and the strain gauge is attached to the restraint means, so the vibration hardly causes measurement errors.
以下本発明装置の一実施例を変位発生素子とし
て電歪素子を用いた場合について説明する。
Hereinafter, an embodiment of the apparatus of the present invention will be described in which an electrostrictive element is used as the displacement generating element.
第１図において、１は変位発生装置で、この変
位発生素子１は駆動電圧を印加させることにより
変位する電歪素子２と、この電歪素子２の変位を
拘束する拘束手段の例えば複数本のボルト３と、
このボルト３に接着され、電歪素子２の変位によ
つてボルト３に発生するひずみを検出する検出手
段の例えばひずみゲージ４などから構成されてい
る。 In FIG. 1, reference numeral 1 denotes a displacement generating device, and the displacement generating element 1 includes an electrostrictive element 2 that is displaced by applying a driving voltage, and a plurality of restraining means for restraining the displacement of the electrostrictive element 2. Bolt 3 and
It consists of a detecting means such as a strain gauge 4, which is bonded to the bolt 3 and detects the strain generated in the bolt 3 due to the displacement of the electrostrictive element 2.
上記のように構成される変位発生装置におい
て、電歪素子２をボルト３による拘束しない場
合、第２図に示す如く電歪素子２の厚さ方向に直
流の駆動電圧を印加すると、電歪素子２はもとの
厚さｔに対してΔtだけ変位する。 In the displacement generating device configured as described above, when the electrostrictive element 2 is not restrained by the bolts 3, when a DC driving voltage is applied in the thickness direction of the electrostrictive element 2 as shown in FIG. 2 is displaced by Δt with respect to the original thickness t.
次に変位状態にある電歪素子２をボルト３によ
り拘束したとき、ボルト３に発生するひずみにつ
いて検討する。 Next, when the electrostrictive element 2 in a displaced state is restrained by the bolt 3, the strain generated in the bolt 3 will be discussed.
まず、圧電ひずみ定数（電歪素子２に単位電界
を与えたときのひずみ率）をｄ、電歪素子２への
駆動電圧をＥとすると、電歪素子２の変位量Δt
は(1)式より得られる。 First, if the piezoelectric strain constant (strain rate when a unit electric field is applied to the electrostrictive element 2) is d, and the drive voltage to the electrostrictive element 2 is E, then the displacement amount Δt of the electrostrictive element 2 is
is obtained from equation (1).
Δt＝ｄ・Ｅ …(1)
次に電歪素子２をボルト３により拘束した場合
の同じ駆動電圧Ｅに対する電歪素子２の変位量は
減少することになるから、電歪素子２の内部には
圧縮応力が発生する。 Δt=d・E (1) Next, when the electrostrictive element 2 is restrained by the bolt 3, the amount of displacement of the electrostrictive element 2 with respect to the same driving voltage E will decrease. generates compressive stress.
ここで、電歪素子２の弾性率をEp、電歪素子
２の厚さをｔとすると、電歪素子２に発生する圧
縮応力σpに起因する圧縮ひずみδpおよび圧縮応力
σpは(2)、(3)式から得られる。 Here, if the elastic modulus of the electrostrictive element 2 is E p and the thickness of the electrostrictive element 2 is t, then the compressive strain δ p and the compressive stress σ p caused by the compressive stress σ p generated in the electrostrictive element 2 are It can be obtained from equations (2) and (3).
δ＝Δt−Δt′／ｔ …(2)
σ＝δp・Ep＝Δt−Δt′／ｔ・Ep …(3)
ここで、Δt′は電歪素子２をボルト３により拘
束したときの変位量である。 δ=Δt−Δt′/t…(2) σ=δ p・E p =Δt−Δt′/t・E p …(3) Here, Δt′ is the value when the electrostrictive element 2 is restrained by the bolt 3. is the amount of displacement.
したがつて、電歪素子が発生する力Fpは、電
歪素子２の面積をSpとした場合、(4)式から得られ
る。 Therefore, the force F p generated by the electrostrictive element can be obtained from equation (4), where S p is the area of the electrostrictive element 2.
Fp＝σp・Sp …(4)
ここで、電歪素子２の面積Spは、電子素子２の
直径をDpとすると、(5)式から得られる。 F p =σ p ·S p (4) Here, the area S p of the electrostrictive element 2 is obtained from equation (5), assuming that the diameter of the electronic element 2 is D p .
Sp＝π・D2 P／４ …(5) (4)式に(3)、(5)式を代入すると、(6)式が得られる。 S p =π·D 2 P /4 (5) By substituting equations (3) and (5) into equation (4), equation (6) is obtained.
Fp＝Δt−Δt′／ｔ・Epπ.D2 P／４ …(6)
一方、ボルト３に発生するひずみをδBとする
と、このδBは(7)式で示される。 F p =Δt−Δt′/t·E p π.D 2 P /4 (6) On the other hand, if the strain occurring in the bolt 3 is δ B , this δ B is expressed by equation (7).
δB＝Δt′／ｔ …(7)
ここで、ボルト３の数をＮ、ボルトの直径を
DB、ボルトのヤング率をEBとすると、ボルト３
が発生する力FBは(8)式で示される。 δ B =Δt'/t...(7) Here, the number of bolts 3 is N, and the diameter of the bolt is
D B and the Young's modulus of the bolt as E B , the bolt 3
The force F B generated is shown by equation (8).
FB＝Δt′／ｔEB・πD2 B／４・Ｎ …(8)
ところで、前記電歪素子２が発生する力Fpと
ボルト３が発生する力FBとは等しいから(9)式が
得られる。 F B =Δt'/tE B・πD 2 B /4・N (8) By the way, since the force F p generated by the electrostrictive element 2 and the force F B generated by the bolt 3 are equal, Equation (9) is obtained.
（Δt−Δt′）Ep・π・D2 P／４・ｔ ＝Δt′・EB・π・D2 B・Ｎ／４・ｔ …(9) (9)式からΔt′を求めると(10)式が得られる。 (Δt−Δt′) E p・π・D 2 P /4・t = Δt′・E B・π・D 2 B・N/4・t …(9) Calculating Δt′ from equation (9) Equation (10) is obtained.
Δt′＝Ep・D2 P・Δt／Ｎ・EB・D2 B＋EpD2 P
＝Ep・D2 P・ｄ・Ｅ／Ｎ・EB・D2 B＋EpD2 P …(10)
(10)式に示すように必要とする変位量Δt′は駆動電
圧Ｅに比例する。また、変位量Δt′の大きさはＮ、
EB、Ep、DB、Dp、ｄ等によつて任意に決めるこ
とができる。 Δt′＝E p・D 2 P・Δt／N・E B・D 2 B ＋E p D 2 P ＝E p・D 2 P・d・E/N・E B・D 2 B ＋E p D 2 P ...(10) As shown in equation (10), the required displacement Δt' is proportional to the drive voltage E. In addition, the magnitude of the displacement Δt′ is N,
It can be arbitrarily determined by E B , E p , D B , D p , d, etc.
そして、駆動電圧Ｅに対する変位量Δt′は第１
図に示す如くボルト３に設けられたひずみゲージ
４の出力を測定することによつて求められる。 Then, the displacement Δt' with respect to the driving voltage E is the first
It is determined by measuring the output of a strain gauge 4 provided on the bolt 3 as shown in the figure.
したがつて、従来のように電歪素子２の駆動電
圧を測定することなく、電歪素子２の変位を直接
的に測定するため、電歪素子２の変位をヒステリ
シス特性の関係なく求めることができる。 Therefore, since the displacement of the electrostrictive element 2 is directly measured without measuring the driving voltage of the electrostrictive element 2 as in the conventional case, the displacement of the electrostrictive element 2 can be determined regardless of the hysteresis characteristics. can.
第３図は本発明装置の他の実施例を示すもの
で、電歪素子２の変位を拘束するボルト５を、前
記ボルト３のように断面積を一様とせずに、切欠
部６を設けて断面積の小さい部分を形成し、この
断面積の小さい部分で主に電歪素子２の変位を発
生するようにすれば、この部分のひずみ率が大き
くなり、精度の高いひずみ測定、すなわち、電歪
素子２の変位量を正確に得ることができる。 FIG. 3 shows another embodiment of the device of the present invention, in which a bolt 5 for restraining the displacement of the electrostrictive element 2 is provided with a notch 6 instead of having a uniform cross-sectional area like the bolt 3. If a portion with a small cross-sectional area is formed and the displacement of the electrostrictive element 2 is mainly generated in this portion with a small cross-sectional area, the strain rate in this portion becomes large, and highly accurate strain measurement is possible. The amount of displacement of the electrostrictive element 2 can be accurately obtained.
尚、本発明の一実施例では、電歪素子を１個に
ついて説明したが、複数個の電歪素子を厚さ方向
に積層したものを拘束した場合にも上記と同様の
効果が得られる。 In one embodiment of the present invention, a single electrostrictive element has been described, but the same effect as described above can be obtained even when a plurality of electrostrictive elements stacked in the thickness direction are restrained.
以上詳細に説明したように本発明によれば、拘
束手段にひずみゲージを設けただけで実現できる
ので、非常に簡単な構成で高精度の変位を測定す
ることができる。また、変位測定のために他の特
別な部品を必要としないので、測定装置などに組
込むことが容易となる。したがつて、本発明の変
位発生装置を、例えば微小変位や微小隙間などの
光学的手段に利用した場合には、大きな効果を発
揮する。
As described in detail above, according to the present invention, it is possible to achieve this by simply providing a strain gauge on the restraint means, and therefore, highly accurate displacement can be measured with a very simple configuration. Furthermore, since no other special parts are required for displacement measurement, it can be easily incorporated into a measuring device or the like. Therefore, when the displacement generating device of the present invention is used for optical means such as minute displacement or minute gap, it exhibits great effects.
第１図は本発明の変位発生装置を概略的に示す
図、第２図は本発明装置における変位発生素子の
動作説明図、第３図は本発明装置における拘束手
段の他の実施例を示す図である。
１…変位発生装置、２…電歪素子、３，５…ボ
ルト、４…ひずみゲージ。
FIG. 1 is a diagram schematically showing the displacement generating device of the present invention, FIG. 2 is an explanatory diagram of the operation of the displacement generating element in the device of the present invention, and FIG. 3 is a diagram showing another embodiment of the restraining means in the device of the present invention. It is a diagram. 1... Displacement generator, 2... Electrostrictive element, 3, 5... Bolt, 4... Strain gauge.
Claims (1)
位する変位発生素子と、該変位発生素子の変位方
向を拘束する拘束手段とを備えた変位発生装置に
おいて、該拘束手段に該変位発生素子の変位を検
出するためのひずみゲージを設けたことを特徴と
する変位発生装置。1. In a displacement generating device that includes a displacement generating element that is displaced in the thickness direction by applying a driving voltage, and a restraining means that restrains the displacement direction of the displacement generating element, the restraining means controls the displacement of the displacement generating element. A displacement generator characterized by being equipped with a strain gauge for detecting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56057149A JPS57172202A (en) | 1981-04-17 | 1981-04-17 | Displacement generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56057149A JPS57172202A (en) | 1981-04-17 | 1981-04-17 | Displacement generator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57172202A JPS57172202A (en) | 1982-10-23 |
| JPH0152911B2 true JPH0152911B2 (en) | 1989-11-10 |
Family
ID=13047505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56057149A Granted JPS57172202A (en) | 1981-04-17 | 1981-04-17 | Displacement generator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57172202A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6263317A (en) * | 1986-09-16 | 1987-03-20 | Hitachi Ltd | Minute displacement generator |
| JPS63140661U (en) * | 1987-03-06 | 1988-09-16 | ||
| JPS63283180A (en) * | 1987-05-15 | 1988-11-21 | Yokogawa Electric Corp | Piezoelectric actuator with displacement sensor |
| JP2580418Y2 (en) * | 1992-11-25 | 1998-09-10 | 株式会社豊田中央研究所 | Displacement measuring device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5427116B2 (en) * | 1973-01-31 | 1979-09-07 | ||
| JPS5716395Y2 (en) * | 1976-12-01 | 1982-04-06 | ||
| JPS55120186A (en) * | 1979-03-09 | 1980-09-16 | Ngk Spark Plug Co Ltd | Piezoelectric element displacement control system |
-
1981
- 1981-04-17 JP JP56057149A patent/JPS57172202A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57172202A (en) | 1982-10-23 |
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