JP3493541B2 - Actuator using electromechanical transducer - Google Patents
Actuator using electromechanical transducerInfo
- Publication number
- JP3493541B2 JP3493541B2 JP11012297A JP11012297A JP3493541B2 JP 3493541 B2 JP3493541 B2 JP 3493541B2 JP 11012297 A JP11012297 A JP 11012297A JP 11012297 A JP11012297 A JP 11012297A JP 3493541 B2 JP3493541 B2 JP 3493541B2
- Authority
- JP
- Japan
- Prior art keywords
- conversion element
- electromechanical conversion
- actuator
- piezoelectric element
- electrode
- 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 - Fee Related
Links
Landscapes
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Description
【0001】[0001]
【発明の属する技術分野】この発明は、電気機械変換素
子を使用したアクチエ−タに関し、特にレンズその他光
学系の精密位置決めなどに適した電気機械変換素子を使
用したアクチエ−タに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator using an electromechanical conversion element, and more particularly to an actuator using an electromechanical conversion element suitable for precision positioning of lenses and other optical systems.
【0002】[0002]
【従来の技術】圧電素子に対し、緩やかな立ち上がり部
とこれに続く急速な立ち下がり部からなる波形の駆動パ
ルスを印加すると、駆動パルスの緩やかな立ち上がり部
では圧電素子が緩やかに厚み方向の伸び変位を生じ、急
速な立ち下がり部では急速に縮み変位を生じる。そこ
で、この特性を利用し、圧電素子に対して上記したよう
な波形の駆動パルスを印加して異なる速度で充放電を繰
り返し、圧電素子に速度の異なる厚み方向の振動を発生
させて圧電素子に固着された駆動軸部材を異なる速度で
往復動させ、駆動軸部材に摩擦結合した移動部材を所定
方向に移動させるリニア型のアクチエ−タが知られてい
る(一例として、特開平6−123830号公報参
照)。2. Description of the Related Art When a drive pulse having a waveform having a gentle rising portion and a rapid falling portion following the same is applied to a piezoelectric element, the piezoelectric element gently extends in the thickness direction at the gently rising portion of the driving pulse. Displacement occurs, and at the rapid falling portion, contraction displacement occurs rapidly. Therefore, by utilizing this characteristic, the drive pulse having the above waveform is applied to the piezoelectric element to repeatedly charge and discharge at different speeds, and the piezoelectric element is caused to vibrate in the thickness direction at different speeds to cause the piezoelectric element to move. A linear type actuator is known in which a fixed drive shaft member is reciprocated at different speeds, and a moving member frictionally coupled to the drive shaft member is moved in a predetermined direction (for example, Japanese Patent Laid-Open No. 6-123830). See the bulletin).
【0003】[0003]
【発明が解決しようとする課題】上記した圧電素子を使
用したリニア型のアクチエ−タでは、駆動軸部材は圧電
素子に接着により結合されているため接着剤の弾性によ
り圧電素子から伝達される駆動力が駆動軸部材に効率よ
く伝達されないという伝達効率の問題や、接着結合部が
剥がれやすいなど信頼性に問題が指摘されていた。さら
に、駆動軸部材と圧電素子とを接着結合する際に軸芯の
ずれや傾きがないように接着結合に細心の注意を必要と
するなど、組み立て工程の困難さなどの問題が指摘され
ていた。この発明は、上記した種々の課題を解決し、駆
動効率がよく、信頼性があり、組み立ての容易な電気機
械変換素子を使用したアクチエ−タの提供を目的とす
る。In the linear actuator using the above-mentioned piezoelectric element, since the drive shaft member is bonded to the piezoelectric element by adhesion, the drive force transmitted from the piezoelectric element by the elasticity of the adhesive. It has been pointed out that there is a problem in transmission efficiency in that force is not efficiently transmitted to the drive shaft member, and a problem in reliability such that the adhesive joint portion is easily peeled off. Furthermore, problems such as difficulty in the assembly process have been pointed out, for example, when the drive shaft member and the piezoelectric element are adhesively bonded, meticulous attention must be paid to the adhesive bonding so that there is no displacement or inclination of the shaft core. . SUMMARY OF THE INVENTION It is an object of the present invention to solve the various problems described above, to provide an actuator using an electromechanical conversion element that has high driving efficiency, reliability, and is easy to assemble.
【0004】[0004]
【課題を解決するための手段】この発明は上記課題を解
決するもので、請求項1の発明は、軸方向両端部付近
に、第1及び第2の電極部が形成された電気機械変換素
子と、前記の電気機械変換素子の軸方向両端部を固定支
持する支持部材と、前記電気機械変換素子に摩擦結合し
た移動部材と、駆動手段とを備え、前記駆動手段は、前
記電気機械変換素子の軸方向両端部付近に形成された第
1及び第2の電極部に対し、それぞれ所定の非対称波形
の正方向の駆動電圧及び所定の非対称波形の負方向の駆
動電圧を印加して電気機械変換素子に速度の異なる往復
振動を発生させ、前記電気機械変換素子に摩擦結合した
移動部材を所定方向に移動させるように制御することを
特徴とする。SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems. The invention of claim 1 is an electromechanical conversion element in which first and second electrode portions are formed near both ends in the axial direction. A supporting member for fixedly supporting both ends of the electromechanical conversion element in the axial direction, a moving member frictionally coupled to the electromechanical conversion element, and a driving means, wherein the driving means includes the electromechanical conversion element. The electromechanical conversion is performed by applying a positive drive voltage and a negative drive voltage with a predetermined asymmetric waveform to the first and second electrode portions formed near both ends in the axial direction, respectively. Reciprocating vibrations having different speeds are generated in the element, and the moving member frictionally coupled to the electromechanical conversion element is controlled to move in a predetermined direction.
【0005】そして、前記電気機械変換素子は円筒状に
形成された圧電セラミツクスから構成され、また、軸方
向両端部付近の第1及び第2の電極部は、それぞれ円筒
の内外に設けられた1対の電極要素から構成される。The electromechanical conversion element is composed of a piezoelectric ceramic formed in a cylindrical shape, and the first and second electrode portions near both ends in the axial direction are provided inside and outside the cylinder, respectively. It is composed of a pair of electrode elements.
【0006】また、前記電気機械変換素子は平板に形成
された圧電セラミツクスを積層して構成してもよい。The electromechanical conversion element may be formed by laminating piezoelectric ceramics formed on a flat plate.
【0007】そして、前記電気機械変換素子に印加され
る駆動電圧は、電気機械変換素子が分極反転の生じない
範囲の駆動電圧とする。Then, the drive voltage applied to the electromechanical conversion element is set to a drive voltage in a range in which polarization reversal does not occur in the electromechanical conversion element.
【0008】[0008]
【発明の実施の形態】以下、この発明の実施の形態につ
いて説明する。図1はこの発明のアクチエ−タの構成を
示す斜視図、図2はその横断面図、図3は図2のA−A
線に沿つた断面図である。図1乃至図3において、11
は基台、12及び13は支持部材、14は管状の圧電素
子で、圧電素子にはスライダ15が嵌合している。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing the structure of the actuator of the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is AA of FIG.
It is sectional drawing which followed the line. In FIGS. 1 to 3, 11
Is a base, 12 and 13 are support members, 14 is a tubular piezoelectric element, and a slider 15 is fitted to the piezoelectric element.
【0009】支持部材12には管状の圧電素子14の内
径に嵌合する環状突起12bが形成されている。また、
支持部材13にはねじ部13sが形成され、ねじ部13
sに螺合して軸方向に移動自在に形成された締付け部材
13aが配置され、締付け部材13aには管状の圧電素
子14の内径に嵌合する環状突起13bが形成されてい
る。圧電素子14の左右の管状端部を環状突起12b及
び環状突起13bに嵌合させ、締め付け部材13aをね
じ込むことにより、圧電素子14を支持部材12と13
の間に軸方向に加圧して強固に固定支持することができ
る。The support member 12 is formed with an annular projection 12b which fits into the inner diameter of the tubular piezoelectric element 14. Also,
A threaded portion 13s is formed on the support member 13, and the threaded portion 13s is formed.
A fastening member 13a that is screwed to s and is formed so as to be movable in the axial direction is arranged, and the fastening member 13a is formed with an annular projection 13b that fits into the inner diameter of the tubular piezoelectric element 14. The left and right tubular ends of the piezoelectric element 14 are fitted to the annular projection 12b and the annular projection 13b, and the tightening member 13a is screwed in, so that the piezoelectric element 14 is supported by the support members 12 and 13.
It is possible to pressurize in the axial direction between and firmly fix and support.
【0010】圧電素子14はPZT(PbZrO3 ・P
bTiO3 )を主成分とする圧電セラミックスから構成
された管状の圧電素子で、その外面の左右にそれぞれ外
部電極16及び17が形成され、また、内面全体にも内
部電極18が形成されている。外部電極16と内部電極
18で第1の電極部が、外部電極17と内部電極18で
第2の電極部が構成される。外部電極16及び17、内
部電極18には適宜の手段によりリ−ド線が接続され、
図示しない駆動源に接続されている。The piezoelectric element 14 is a PZT (PbZrO 3 .P
This is a tubular piezoelectric element made of piezoelectric ceramics containing bTiO 3 as a main component, and external electrodes 16 and 17 are formed on the left and right of the outer surface of the tubular piezoelectric element, and an internal electrode 18 is also formed on the entire inner surface. The outer electrode 16 and the inner electrode 18 constitute a first electrode portion, and the outer electrode 17 and the inner electrode 18 constitute a second electrode portion. Lead wires are connected to the external electrodes 16 and 17 and the internal electrode 18 by appropriate means,
It is connected to a drive source (not shown).
【0011】スライダ15は、図3に示すように中央部
に管状の圧電素子14の外側に嵌合する孔15aと、孔
15aを横切るスリツト15bが形成されており、スラ
イダ15は孔15aの部分で管状の圧電素子14と摩擦
結合している。スライダ15にはスリツト15bで分割
された上側部分にビス19の貫通孔15dが、分割され
た下側部分にビス孔15cが形成されており、貫通孔1
5dに挿入したビス19をビス孔15cに締め付けるこ
とで、スライダ15と管状の圧電素子14との摩擦結合
力を調整するように構成されている。スライダと管状の
圧電素子との摩擦結合力を調整するには、このほか適宜
の手段、例えばスライダ15を上下2つの部材に分割
し、2つの部材をバネを介してねじで締め付ける構成な
どを適宜採用することができる。As shown in FIG. 3, the slider 15 has a hole 15a which fits to the outside of the tubular piezoelectric element 14 and a slit 15b which crosses the hole 15a, and the slider 15 has a portion corresponding to the hole 15a. Is frictionally coupled to the tubular piezoelectric element 14. The slider 15 has a through hole 15d for the screw 19 formed in the upper portion divided by the slit 15b, and a screw hole 15c formed in the divided lower portion.
By tightening the screw 19 inserted in 5d into the screw hole 15c, the frictional coupling force between the slider 15 and the tubular piezoelectric element 14 is adjusted. In order to adjust the frictional coupling force between the slider and the tubular piezoelectric element, other suitable means, for example, a structure in which the slider 15 is divided into two members, an upper and a lower member, and the two members are fastened with a screw via a spring, are appropriately used. Can be adopted.
【0012】ここで、図4を参照してPZT系の圧電素
子の特性について説明する。この圧電素子は未分極の初
期状態から正電界を加えると、電界方向に沿つて分極
し、同時に電界方向に伸び変位が生じ、電界方向と垂直
方向に縮み変位が生じる(図4で(1) の状態)。緩やか
に電界を弱めていくと変位も減少していくが、電界が零
になつても分極状態が残り、残留歪みΔLrが残る(図
4で(2) の状態)。The characteristics of the PZT type piezoelectric element will be described with reference to FIG. When a positive electric field is applied from an unpolarized initial state, this piezoelectric element is polarized along the direction of the electric field, and at the same time, an expansion displacement is generated in the electric field direction and a contraction displacement is generated in the direction perpendicular to the electric field direction ((1) in FIG. 4). State). Although the displacement decreases as the electric field is gradually weakened, the polarization state remains and the residual strain ΔLr remains even when the electric field becomes zero (state (2) in FIG. 4).
【0013】電界を負方向(先と逆方向)に加えると、
変位が初期状態の零まで戻り(図4で(3) の状態)、分
極方向が反転して再び伸び方向に変位が生じる(図4で
(4)の状態)。緩やかに電界を弱めていくと変位も減少
していくが、電界が零になつても分極状態が残り、残留
歪みΔLrが残る(図4で(2) の状態)。電界を正方向
に加えると、変位が初期状態の零まで戻り(図4で(5)
の状態)、分極方向が反転して再び伸び方向に変位が生
じる(図4で(1) の状態)。When an electric field is applied in the negative direction (the opposite direction to the previous direction),
The displacement returns to zero in the initial state (state (3) in Fig. 4), the polarization direction is reversed, and the displacement occurs again in the extension direction (Fig. 4).
(State of (4)). Although the displacement decreases as the electric field is gradually weakened, the polarization state remains and the residual strain ΔLr remains even when the electric field becomes zero (state (2) in FIG. 4). When the electric field is applied in the positive direction, the displacement returns to zero in the initial state ((5) in Fig. 4).
State), the polarization direction is reversed and displacement occurs again in the extension direction (state (1) in FIG. 4).
【0014】圧電素子は以上説明した特性を示すが、こ
の発明では電界の変化に対して変位が略比例する図4で
(2) で示す付近の領域、即ち図5で示す領域で使用す
る。この領域では、電界強度が零の点を原点とすると、
伸び変位(縮み変位)ΔLは以下の式で表される。The piezoelectric element has the characteristics described above, but in the present invention, the displacement is substantially proportional to the change of the electric field in FIG.
It is used in the area near (2), that is, in the area shown in FIG. In this area, if the point where the electric field strength is zero is the origin,
The elongation displacement (contraction displacement) ΔL is expressed by the following formula.
【0015】ΔL=LdV/t ここで、L:圧電素子の長さ、 V:圧電素子に印加する電圧、 t:圧電素子の電極間の厚み、 d:圧電定数。ΔL = LdV / t Where L is the length of the piezoelectric element, V: voltage applied to the piezoelectric element, t: thickness between electrodes of the piezoelectric element, d: Piezoelectric constant.
【0016】即ち、図5で示す領域においては、伸び変
位(縮み変位)ΔLは圧電素子の長さLと圧電素子に印
加する電圧Vに比例し、圧電素子の電極間の厚みtに反
比例する。That is, in the region shown in FIG. 5, the elongation displacement (contraction displacement) ΔL is proportional to the length L of the piezoelectric element and the voltage V applied to the piezoelectric element, and is inversely proportional to the thickness t between the electrodes of the piezoelectric element. .
【0017】図6はアクチエ−タの制御回路を示すブロ
ツク図で、制御回路はCPU51とパルス発生回路5
2、制御部53、54から構成される。なお、パルス発
生回路55、制御部56は図10、及び図12に示すア
クチエ−タの制御に使用される回路要素であり、この部
分は後で図10、及び図12を参照して説明する。FIG. 6 is a block diagram showing the control circuit of the actuator. The control circuit includes a CPU 51 and a pulse generation circuit 5.
2. It is composed of control units 53 and 54. The pulse generation circuit 55 and the control unit 56 are circuit elements used for controlling the actuator shown in FIGS. 10 and 12, and this portion will be described later with reference to FIGS. 10 and 12. .
【0018】パルス発生回路52はCPU51の制御の
下に図8の(a)に示すような緩やかな立上り部と急速
な立下り部を持つ駆動パルス(正電圧パルス)、図8の
(b)に示すような緩やかな立上り部と急速な立下り部
を持つ逆極性の駆動パルス(負電圧パルス)を発生さ
せ、制御部53、54を経て外部電極16、17に印加
する。また、内部電極18は接地されているものとす
る。Under the control of the CPU 51, the pulse generation circuit 52 has a drive pulse (a positive voltage pulse) having a gentle rising portion and a rapid falling portion as shown in FIG. 8A, and FIG. 8B. A drive pulse (negative voltage pulse) of opposite polarity having a gentle rising portion and a rapid falling portion as shown in (3) is generated and applied to the external electrodes 16 and 17 via the control units 53 and 54. In addition, the internal electrode 18 is assumed to be grounded.
【0019】次に、この発明のアクチエ−タの動作を説
明する。図7の(a)乃至(d)は図1、図2に示すア
クチエ−タの動作を説明する模式図で、動作を理解しや
すいように実際の動きを誇張して示してある。Next, the operation of the actuator of the present invention will be described. 7A to 7D are schematic views for explaining the operation of the actuator shown in FIGS. 1 and 2, and the actual movement is exaggerated for easy understanding of the operation.
【0020】まず、管状の圧電素子14の外部電極16
と内部電極18で構成される第1電極部、外部電極17
と内部電極18で構成される第2電極部は、予め製造時
に共に半径方向に同方向に分極され、図4の(2) の状態
となつている。分極させるためには、先に述べた圧電素
子の特性を利用し、所定電圧の直流を外部電極16と内
部電極18の間、外部電極17と内部電極18に印加し
て同一方向の電界を発生させることで分極することがで
きる。First, the external electrode 16 of the tubular piezoelectric element 14
A first electrode portion composed of an internal electrode 18 and an external electrode 17
The second electrode portion composed of the internal electrode 18 and the internal electrode 18 is preliminarily polarized in the same direction in the radial direction at the time of manufacture, and is in the state of (2) in FIG. In order to polarize, using the characteristics of the piezoelectric element described above, a direct current of a predetermined voltage is applied between the external electrode 16 and the internal electrode 18 and between the external electrode 17 and the internal electrode 18 to generate an electric field in the same direction. It can be polarized.
【0021】図7の(a)は圧電素子14の第1及び第
2電極部が共に半径方向に同方向に分極されており、駆
動パルスが印加されていない初期状態を示す図である。FIG. 7A is a diagram showing an initial state in which the first and second electrode portions of the piezoelectric element 14 are both polarized in the same radial direction and no drive pulse is applied.
【0022】この状態で外部電極16に図8の(a)に
示すような緩やかな立上り部と急速な立下り部を持つ駆
動パルス(正電圧パルス)を印加し、外部電極17に図
8の(b)に示すような緩やかな立上り部と急速な立下
り部を持つ逆極性の駆動パルス(負電圧パルス)を印加
すると、駆動パルスの緩やかな立上り部では外部電極1
6の部分(第1電極部)は伸び変位を生じ、外部電極1
7の部分(第2電極部)は縮み変位を生じて図7の
(b)に示す状態となり、圧電素子14の中央付近は矢
印a方向に移動する。この結果、圧電素子14に摩擦結
合したスライダ15はΔLだけ矢印a方向に移動するこ
とになる。In this state, a drive pulse (positive voltage pulse) having a gentle rising portion and a rapid falling portion as shown in FIG. 8A is applied to the external electrode 16 and the external electrode 17 of FIG. When a drive pulse (negative voltage pulse) of opposite polarity having a gentle rising portion and a rapid falling portion as shown in (b) is applied, the external electrode 1 is generated at the gentle rising portion of the driving pulse.
The portion 6 (first electrode portion) undergoes extension displacement, and the external electrode 1
The portion 7 (second electrode portion) is contracted and displaced to the state shown in FIG. 7B, and the vicinity of the center of the piezoelectric element 14 moves in the direction of arrow a. As a result, the slider 15 frictionally coupled to the piezoelectric element 14 moves in the direction of the arrow a by ΔL.
【0023】次に、駆動パルスの急速な立下がり部では
外部電極16、17に発生した変位は急速に縮み変位を
生じて元の状態に戻る。このとき、スライダ15は、そ
の慣性力がスライダ15と圧電素子14との間の摩擦結
合力に打ち勝ち、スライダ15と圧電素子14との間に
滑りを生じてその位置に留まる方向に作用するので、結
果としてスライダ15は、多少引き戻されるがΔXだけ
矢印a方向に移動する。図7の(c)はこの状態を示
す。Next, at the rapid falling edge of the drive pulse, the displacement generated in the external electrodes 16 and 17 rapidly contracts and returns to the original state. At this time, since the inertial force of the slider 15 overcomes the frictional coupling force between the slider 15 and the piezoelectric element 14, the slider 15 acts in such a direction as to cause a slip between the slider 15 and the piezoelectric element 14 and stay at that position. As a result, although the slider 15 is pulled back to some extent, it moves in the direction of arrow a by ΔX. FIG. 7C shows this state.
【0024】図8の(a)及び(b)に示すような緩や
かな立上り部と急速な立下り部を持つ駆動パルスを外部
電極16及び17に印加して上記動作を繰り返すこと
で、スライダ15を圧電素子14との間に滑りを生じつ
つ矢印a方向に移動させることができる。繰り返し周波
数を可聴周波数以上、即ち20kHz以上の超音波領域
とすることで、人の耳に不快感を与えるノイズの発生な
しに高速駆動を行うことができる。By applying a drive pulse having a gentle rising portion and a rapid falling portion as shown in FIGS. 8A and 8B to the external electrodes 16 and 17 and repeating the above operation, the slider 15 Can be moved in the arrow a direction while causing a slip with the piezoelectric element 14. By setting the repetition frequency to the audible frequency or higher, that is, to the ultrasonic region of 20 kHz or higher, high-speed driving can be performed without the generation of noise that causes discomfort to the human ear.
【0025】スライダ15を矢印aと反対方向に移動さ
せるには、外部電極17に図8の(a)に示すような緩
やかな立上り部と急速な立下り部を持つ駆動パルス(正
電圧パルス)を、外部電極16に図8の(b)に示すよ
うな緩やかな立上り部と急速な立下り部を持つ駆動パル
ス(負電圧パルス)を印加することで達成することがで
きる。To move the slider 15 in the direction opposite to the arrow a, a drive pulse (a positive voltage pulse) having a gentle rising portion and a rapid falling portion as shown in FIG. Can be achieved by applying a drive pulse (negative voltage pulse) having a gently rising portion and a rapidly falling portion as shown in FIG. 8B to the external electrode 16.
【0026】図9は、図8の(a)及び(b)に示す駆
動パルスを、それぞれ負方向及び正方向に偏奇させ、電
位零の上下に振り分けた駆動パルスの波形を示すもので
ある。この駆動パルスを外部電極16及び17に印加す
ると、最初は外部電極16の部分は縮み変位を生じ、外
部電極17の部分は伸び変位を生じて図7の(d)に示
す状態となり、駆動パルス電圧の変化により順次、図7
の(b)、図7の(c)の状態に変化する。駆動パルス
を電位零の上下に振り分けることで、図5に示した分極
反転が生じるまでの電界領域内での駆動パルスの振幅を
大きく取ることができ、駆動速度を向上させることがで
きる。FIG. 9 shows the waveforms of the drive pulses shown in FIGS. 8A and 8B, which are biased in the negative and positive directions and distributed above and below zero potential. When this drive pulse is applied to the external electrodes 16 and 17, the external electrode 16 portion initially undergoes contraction displacement, and the external electrode 17 portion undergoes extension displacement, resulting in the state shown in (d) of FIG. Figure 7
7B, the state of FIG. 7C changes. By allocating the drive pulse above and below the zero potential, the amplitude of the drive pulse in the electric field region until the polarization inversion shown in FIG. 5 can be made large, and the drive speed can be improved.
【0027】以上の説明では、管状の圧電素子14の外
部電極16と内部電極18で構成される第1電極部、外
部電極17と内部電極18で構成される第2電極部は共
に半径方向に同方向に分極されているものとして説明し
た。しかし、外部電極16と内部電極18で構成される
第1電極部と、外部電極17と内部電極18で構成され
る第2電極部とを互いに逆方向に分極させたものでもよ
い。In the above description, the first electrode portion composed of the outer electrode 16 and the inner electrode 18 and the second electrode portion composed of the outer electrode 17 and the inner electrode 18 of the tubular piezoelectric element 14 are both arranged in the radial direction. It has been described as being polarized in the same direction. However, the first electrode portion composed of the outer electrode 16 and the inner electrode 18 and the second electrode portion composed of the outer electrode 17 and the inner electrode 18 may be polarized in opposite directions.
【0028】逆方向に分極させるためには、製造時に外
部電極16と内部電極18の間に所定電圧の直流を印加
し、外部電極17と内部電極18にはこれと逆極性の直
流を印加して互いに逆方向の電界を発生させればよい。
この場合は、外部電極16及び17に印加する駆動パル
スの電圧波形を変える必要がなく全く同じ波形の駆動パ
ルスでよい。In order to polarize in the opposite direction, a direct current having a predetermined voltage is applied between the outer electrode 16 and the inner electrode 18 during manufacturing, and a direct current having a reverse polarity is applied to the outer electrode 17 and the inner electrode 18. The electric fields may be generated in opposite directions.
In this case, it is not necessary to change the voltage waveform of the drive pulse applied to the external electrodes 16 and 17, and the drive pulse having exactly the same waveform may be used.
【0029】図10は、図1乃至図3で説明したスライ
ダ15を導電性材料で構成し、スライダ15に正方向の
電圧を印加して圧電素子14のスライダ15が摩擦結合
している部分14aに電界をかけるようにしたアクチエ
−タを示す断面図である。この構成によれば、スライダ
15に印加する電圧を加減することでスライダ15と圧
電素子14との間の摩擦結合力を制御することができ
る。In FIG. 10, the slider 15 described in FIGS. 1 to 3 is made of a conductive material, and a positive voltage is applied to the slider 15 so that the slider 15 of the piezoelectric element 14 is frictionally coupled to the portion 14a. FIG. 6 is a cross-sectional view showing an actuator configured to apply an electric field to the actuator. According to this configuration, the frictional coupling force between the slider 15 and the piezoelectric element 14 can be controlled by adjusting the voltage applied to the slider 15.
【0030】即ち、スライダ15と内部電極18との間
に正方向の電圧を印加して電界を発生させると、この部
分の圧電素子14aは管の厚み方向に伸びようとし、管
の円周方向には縮もうとするが、管の厚みは管の半径及
び円周長さに比較して小さいので、管は図10に示すよ
うに半径方向に収縮する。That is, when a positive voltage is applied between the slider 15 and the internal electrode 18 to generate an electric field, the piezoelectric element 14a in this portion tends to extend in the thickness direction of the tube, and the piezoelectric element 14a in this direction extends in the circumferential direction of the tube. However, since the thickness of the tube is small compared to the radius and the circumferential length of the tube, the tube shrinks in the radial direction as shown in FIG.
【0031】そこで、管状の圧電素子14に、先に説明
したように、外部電極16に図11の(a)、及び外部
電極17に図11の(b)に示す駆動パルスを印加する
が、駆動パルスの緩やかな立上り部を印加する時点では
スライダ15に電圧を印加せず、スライダ15と圧電素
子14との摩擦結合状態を維持させてスライダ15を移
動させる。Therefore, as described above, the drive pulse shown in FIG. 11A is applied to the external electrode 16 and the drive pulse shown in FIG. 11B is applied to the external electrode 17 to the tubular piezoelectric element 14. No voltage is applied to the slider 15 at the time of applying the gently rising portion of the drive pulse, and the slider 15 is moved while maintaining the frictionally coupled state between the slider 15 and the piezoelectric element 14.
【0032】外部電極16及び17に駆動パルスの急速
な立下り部を印加する時点では図11の(c)に示すよ
うにスライダ15に正方向の電圧を印加して、圧電素子
14の管状部14aを半径方向に収縮させ、スライダ1
5と管状部14aとの摩擦結合力を弱めて滑りやすく制
御する。At the time when the rapid falling edge of the drive pulse is applied to the external electrodes 16 and 17, a positive voltage is applied to the slider 15 as shown in FIG. 14a is contracted in the radial direction to move the slider 1
5 to weaken the frictional coupling force between the tubular portion 14a and the tubular portion 14a to control slipperiness.
【0033】以上の制御はアクチエ−タの制御回路で実
施される。即ち、図6に示すアクチエ−タの制御回路に
おいて、パルス発生回路52、制御部53、54のほ
か、さらにパルス発生回路55、制御部56が加えられ
る。パルス発生回路52はCPU51の制御の下に図1
1の(a)に示すような緩やかな立上り部と急速な立下
り部を持つ駆動パルス(正電圧パルス)、図11の
(b)に示すような緩やかな立上り部と急速な立下り部
を持つ逆極性の駆動パルス(負電圧パルス)を発生さ
せ、制御部53、54を経て外部電極16、17に印加
する。内部電極18は接地されているものとする。The above control is carried out by the control circuit of the actuator. That is, in the control circuit of the actuator shown in FIG. 6, in addition to the pulse generation circuit 52 and the control units 53 and 54, the pulse generation circuit 55 and the control unit 56 are further added. The pulse generation circuit 52 is controlled by the CPU 51 as shown in FIG.
A drive pulse (positive voltage pulse) having a gentle rising portion and a rapid falling portion as shown in (a) of 1 and a gentle rising portion and a rapid falling portion as shown in (b) of FIG. A drive pulse (negative voltage pulse) having the opposite polarity is generated and applied to the external electrodes 16 and 17 via the control units 53 and 54. The internal electrode 18 is grounded.
【0034】パルス発生回路55はCPU51の制御の
下に図11の(c)に示すような前記した駆動パルスの
急速な立下り部に応答する時点で、急速な立下り部に略
等しい幅の矩形パルスを発生させ、制御部56を経てス
ライダ15に印加する。Under the control of the CPU 51, the pulse generation circuit 55 responds to the rapid falling edge of the drive pulse as shown in FIG. 11C, and has a width substantially equal to the rapid falling edge. A rectangular pulse is generated and applied to the slider 15 via the control unit 56.
【0035】これにより、駆動パルスの急速な立下り部
に応答する時点では、スライダ15と圧電素子14との
間はスライダ15に電圧を印加しない構成のものよりも
滑りやすくなり、結果としてスライダ15を、先の場合
の移動距離ΔXよりも大きいΔLに近い寸法だけ矢印a
方向に移動させることができる。As a result, at the time of responding to the rapid trailing edge of the drive pulse, the slider 15 and the piezoelectric element 14 are more slippery than those of the structure in which no voltage is applied to the slider 15, and as a result, the slider 15 is moved. The arrow a by a dimension close to ΔL, which is larger than the moving distance ΔX in the previous case.
Can be moved in any direction.
【0036】また、図11の(d)に示すように、外部
電極16及び17に駆動パルスの緩やかな立上り部を印
加する時点では、スライダ15に負方向の電圧を印加し
て圧電素子14の部分14aを半径方向に膨脹させてス
ライダ15と圧電素子14との摩擦結合状態をより強く
維持させ、外部電極16及び17に駆動パルスの急速な
立下り部を印加する時点では、スライダ15に正方向の
電圧を印加して圧電素子14の管状部14aを半径方向
に収縮させてスライダ15と管状部14aとの摩擦結合
力を弱めて滑りやすく制御してもよい。Further, as shown in FIG. 11D, at the time of applying the gradual rising portion of the drive pulse to the external electrodes 16 and 17, a voltage in the negative direction is applied to the slider 15 to cause the piezoelectric element 14 to move. At the time when the portion 14a is expanded in the radial direction to maintain the frictional coupling state between the slider 15 and the piezoelectric element 14 more strongly and the rapid falling portion of the driving pulse is applied to the external electrodes 16 and 17, the slider 15 is positively moved. A voltage in the direction may be applied to contract the tubular portion 14a of the piezoelectric element 14 in the radial direction to weaken the frictional coupling force between the slider 15 and the tubular portion 14a to control slipperiness.
【0037】図12は、図10に示した構成において、
スライダ15を導電性材料で構成する代わりに圧電素子
14上のスライダ15が移動する範囲に第3電極19を
設けたものである。FIG. 12 shows the configuration shown in FIG.
Instead of forming the slider 15 from a conductive material, the third electrode 19 is provided on the piezoelectric element 14 in a range where the slider 15 moves.
【0038】この構成では、図6に示すアクチエ−タの
制御回路のパルス発生回路55から駆動パルスの急速な
立下り部に応答する時点で、図11の(c)に示すよう
な急速な立下り部に略等しい幅の矩形パルスを発生さ
せ、制御部56を経て第3電極19に印加する。これに
より駆動パルスの急速な立下り部に応答する時点で圧電
素子14の電極19の部分を半径方向に収縮させること
ができるから、図10に示した構成のアクチエ−タと同
様にスライダ15と管状部14aとの摩擦結合力を弱め
て滑りやすくすることができる。In this structure, at the time of responding to the rapid falling edge of the driving pulse from the pulse generating circuit 55 of the actuator control circuit shown in FIG. 6, the rapid rising edge as shown in FIG. 11 (c). A rectangular pulse having a substantially equal width is generated in the descending portion and is applied to the third electrode 19 via the control unit 56. As a result, the portion of the electrode 19 of the piezoelectric element 14 can be contracted in the radial direction at the time of responding to the rapid falling portion of the drive pulse, and thus the slider 15 and the slider 15 are formed in the same manner as the actuator having the configuration shown in FIG. It is possible to weaken the frictional coupling force with the tubular portion 14a to make it slippery.
【0039】また、この場合も、図11の(d)に示す
ように、外部電極16及び17に駆動パルスの緩やかな
立上り部を印加する時点では、圧電素子14の部分14
aを半径方向に膨脹させてスライダ15と圧電素子14
との摩擦結合状態をより強く維持させ、駆動パルスの急
速な立下り部を印加する時点では、圧電素子14の電極
19の部分を半径方向に収縮させて摩擦結合力を弱めて
滑りやすく制御することができる。Also in this case, as shown in FIG. 11D, at the time of applying the gentle rising portion of the driving pulse to the external electrodes 16 and 17, the portion 14 of the piezoelectric element 14 is applied.
a is radially expanded to expand the slider 15 and the piezoelectric element 14
At the time of applying a rapid trailing edge of the drive pulse while further maintaining the frictionally coupled state with the, the portion of the electrode 19 of the piezoelectric element 14 is contracted in the radial direction to weaken the frictional coupling force and control slippery. be able to.
【0040】以上説明しアクチエ−タでは、圧電素子と
して管状の圧電素子を使用しているが、図13に示すよ
うな、圧電素子として平板状の単位圧電素子21、2
2、23を積層し、積層された圧電素子21、22、2
3の端部付近に電極31、32、33、34、及び3
5、36、37、38、22を設けた構成のものとし、
これにスライダを摩擦結合した構成とすることもでき
る。In the actuator described above, a tubular piezoelectric element is used as the piezoelectric element. However, as shown in FIG. 13, flat unit piezoelectric elements 21 and 2 are used as the piezoelectric elements.
Piezoelectric elements 21, 22, and 2 in which 2 and 23 are laminated
Electrodes 31, 32, 33, 34 and 3 near the end of 3
5, 36, 37, 38, 22 are provided,
A slider may be frictionally coupled to the slider.
【0041】[0041]
【発明の効果】以上説明したとおり、この発明のアクチ
エ−タは、円筒状の電気機械変換素子の軸方向両端部を
固定支持し、電気機械変換素子に移動部材を摩擦結合さ
せたものであつて、電気機械変換素子の軸方向両端部付
近にそれぞれ形成された第1及び第2の電極にそれぞれ
所定の非対称波形の正方向の駆動電圧及び負方向の駆動
電圧を印加して速度の異なる往復振動を発生させ、前記
電気機械変換素子に摩擦結合した移動部材を所定方向に
移動させるように構成したものである。As described above, the actuator of the present invention comprises a cylindrical electromechanical conversion element which is fixedly supported at both axial ends thereof, and a moving member is frictionally coupled to the electromechanical conversion element. Then, a positive driving voltage and a negative driving voltage having predetermined asymmetric waveforms are applied to the first and second electrodes formed near both ends of the electromechanical conversion element in the axial direction, respectively, and reciprocating at different speeds. The moving member frictionally coupled to the electromechanical conversion element is caused to move in a predetermined direction by generating vibration.
【0042】この構成によれば、電気機械変換素子に別
体の駆動軸部材などを接着固定する構成部分がないので
機械的強度が大きく、伝達効率が改善されるほか、接着
結合部の剥離などの発生のおそれもないから高い信頼性
を確保することができ、また、部品点数が少なく接着結
合部がないので、組み立てが容易なアクチエ−タを提供
することができる。According to this structure, since the electromechanical conversion element does not have a constituent portion for adhering and fixing a separate drive shaft member or the like, the mechanical strength is large, the transmission efficiency is improved, and the adhesive joint portion is peeled off. It is possible to ensure high reliability because there is no possibility of occurrence of the above, and since there are few parts and there is no adhesive joint, it is possible to provide an actuator which is easy to assemble.
【図1】この発明の電気機械変換素子を使用したアクチ
エ−タの構成を示す斜視図。FIG. 1 is a perspective view showing the configuration of an actuator using the electromechanical conversion element of the present invention.
【図2】図1に示すアクチエ−タの横断面図。2 is a cross-sectional view of the actuator shown in FIG.
【図3】図2のA−A線に沿つたスライダの断面図。3 is a cross-sectional view of the slider taken along the line AA of FIG.
【図4】PZT系の圧電素子の特性を説明する図。FIG. 4 is a diagram illustrating characteristics of a PZT-based piezoelectric element.
【図5】PZT系の圧電素子における電界と変位の略比
例する領域を説明する図。FIG. 5 is a diagram illustrating a region in which the electric field and the displacement of the PZT-based piezoelectric element are substantially proportional to each other.
【図6】アクチエ−タの制御回路を示すブロツク図。FIG. 6 is a block diagram showing the control circuit of the actuator.
【図7】この発明のアクチエ−タの動作を説明する図。FIG. 7 is a diagram for explaining the operation of the actuator of the present invention.
【図8】圧電素子に印加する駆動パルスの波形を説明す
る図。FIG. 8 is a diagram illustrating a waveform of a drive pulse applied to a piezoelectric element.
【図9】圧電素子に印加する駆動パルスの波形の他の例
を説明する図。FIG. 9 is a diagram illustrating another example of the waveform of the drive pulse applied to the piezoelectric element.
【図10】スライダを導電性材料としたアクチエ−タの
構成を示す断面図。FIG. 10 is a sectional view showing the structure of an actuator using a slider as a conductive material.
【図11】図9に示すアクチエ−タの駆動パルスの波形
を説明する図。FIG. 11 is a diagram for explaining the waveform of a drive pulse of the actuator shown in FIG.
【図12】スライダ移動範囲に対応する圧電素子上に第
3電極を設けたアクチエ−タの構成を示す断面図。FIG. 12 is a sectional view showing a structure of an actuator in which a third electrode is provided on a piezoelectric element corresponding to a slider movement range.
【図13】平板状の単位素子を積層した圧電素子の構成
を示す斜視図。FIG. 13 is a perspective view showing the configuration of a piezoelectric element in which flat unit elements are stacked.
11 基台 12、13 支持部材 14 管状の圧電素子 15 スライダ 15b スリツト 16、17 外部電極 18 内部電極 19 第3電極 11 bases 12, 13 Support member 14 Tubular piezoelectric element 15 slider 15b slit 16, 17 External electrode 18 internal electrodes 19 Third electrode
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平7−312884(JP,A) 特開 平4−69701(JP,A) 特開 平5−126518(JP,A) 特開 昭60−219972(JP,A) 特開 平3−183378(JP,A) 特開 平4−212910(JP,A) (58)調査した分野(Int.Cl.7,DB名) H02N 2/00 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-7-312884 (JP, A) JP-A-4-69701 (JP, A) JP-A-5-126518 (JP, A) JP-A-60- 219972 (JP, A) JP-A-3-183378 (JP, A) JP-A-4-212910 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) H02N 2/00
Claims (5)
極部が形成された電気機械変換素子と、 前記の電気機械変換素子の軸方向両端部を固定支持する
支持部材と、 前記電気機械変換素子に摩擦結合した移動部材と、 駆動手段と、 を備え、 前記駆動手段は、前記電気機械変換素子の軸方向両端部
付近に形成された第1及び第2の電極部に対し、それぞ
れ所定の非対称波形の正方向の駆動電圧及び所定の非対
称波形の負方向の駆動電圧を印加して電気機械変換素子
に速度の異なる往復振動を発生させ、前記電気機械変換
素子に摩擦結合した移動部材を所定方向に移動させるよ
うに制御することを特徴とする電気機械変換素子を使用
したアクチエ−タ。1. An electromechanical conversion element in which first and second electrode portions are formed near both axial end portions, and a support member for fixedly supporting both axial end portions of the electromechanical conversion element, A moving member frictionally coupled to the electromechanical conversion element; and a driving means, wherein the driving means is provided with respect to the first and second electrode portions formed near both ends in the axial direction of the electromechanical conversion element, A positive driving voltage having a predetermined asymmetrical waveform and a negative driving voltage having a predetermined asymmetrical waveform are applied to generate reciprocating vibrations having different speeds in the electromechanical conversion element, and the movement is frictionally coupled to the electromechanical conversion element. An actuator using an electromechanical conversion element, characterized in that the member is controlled to move in a predetermined direction.
れた圧電セラミツクスから構成されることを特徴とする
請求項1記載の電気機械変換素子を使用したアクチエ−
タ。2. The actuator using the electromechanical conversion element according to claim 1, wherein the electromechanical conversion element is composed of a piezoelectric ceramic formed in a cylindrical shape.
Ta.
近の第1及び第2の電極部は、それぞれ円筒の内外に設
けられた1対の電極要素から構成されることを特徴とす
る請求項1記載の電気機械変換素子を使用したアクチエ
−タ。3. The first and second electrode portions near both ends in the axial direction of the electromechanical conversion element are each composed of a pair of electrode elements provided inside and outside the cylinder. An actuator using the electromechanical conversion element according to Item 1.
た圧電セラミツクスを積層して構成されることを特徴と
する請求項1記載の電気機械変換素子を使用したアクチ
エ−タ。4. The actuator using the electromechanical conversion element according to claim 1, wherein the electromechanical conversion element is formed by laminating piezoelectric ceramics formed on a flat plate.
電圧は、電気機械変換素子が分極反転の生じない範囲の
駆動電圧であることを特徴とする請求項1乃至請求項4
のいずれかに記載の電気機械変換素子を使用したアクチ
エ−タ。5. The driving voltage applied to the electromechanical conversion element is a driving voltage in a range in which polarization reversal does not occur in the electromechanical conversion element.
An actuator using the electromechanical conversion element according to any one of 1.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11012297A JP3493541B2 (en) | 1997-04-14 | 1997-04-14 | Actuator using electromechanical transducer |
US09/060,067 US6140750A (en) | 1997-04-14 | 1998-04-14 | Actuator using electromechanical transducer and apparatus employing the actuator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11012297A JP3493541B2 (en) | 1997-04-14 | 1997-04-14 | Actuator using electromechanical transducer |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH10290586A JPH10290586A (en) | 1998-10-27 |
JP3493541B2 true JP3493541B2 (en) | 2004-02-03 |
Family
ID=14527596
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11012297A Expired - Fee Related JP3493541B2 (en) | 1997-04-14 | 1997-04-14 | Actuator using electromechanical transducer |
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JP (1) | JP3493541B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2010032826A1 (en) * | 2008-09-22 | 2012-02-16 | アルプス電気株式会社 | Support device for vibration actuator |
-
1997
- 1997-04-14 JP JP11012297A patent/JP3493541B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH10290586A (en) | 1998-10-27 |
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