JPH11122957A - Ultrasonic motor and manufacture thereof - Google Patents
Ultrasonic motor and manufacture thereofInfo
- Publication number
- JPH11122957A JPH11122957A JP9293470A JP29347097A JPH11122957A JP H11122957 A JPH11122957 A JP H11122957A JP 9293470 A JP9293470 A JP 9293470A JP 29347097 A JP29347097 A JP 29347097A JP H11122957 A JPH11122957 A JP H11122957A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- piezoelectric element
- ultrasonic motor
- electrodes
- driving
- 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
Landscapes
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Abstract
Description
【０００１】[0001]
【技術分野】本発明は，耐久性等に優れた超音波モータ
及びその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor having excellent durability and a method for manufacturing the same.
【０００２】[0002]
【従来技術】超音波モータは，後述する図４に示すごと
く，リング状の圧電素子１０と，圧電素子１０に貼設し
た振動体２と，振動体２に加圧当接させた回転体３とを
有してなる。そして，上記圧電素子１０に位相が９０度
異なる２種類の高周波電圧を印加することにより上記振
動体２に進行波を発生させて回転体３を摩擦駆動するタ
イプのモータである。2. Description of the Related Art As shown in FIG. 4, which will be described later, an ultrasonic motor is composed of a ring-shaped piezoelectric element 10, a vibrating body 2 attached to the piezoelectric element 10, and a rotating body 3 pressed against the vibrating body 2. And The motor is of a type in which a traveling wave is generated in the vibrating body 2 by applying two kinds of high-frequency voltages having phases different by 90 degrees to the piezoelectric element 10 to frictionally drive the rotating body 3.
【０００３】即ち，図８に示すごとく，振動体２に進行
波が発生した場合には，振動体２の表面が楕円運動をし
ながら上下動する。そのため，振動体２に接触している
回転体３は，振動体２の表面の上記楕円運動に伴って進
行波の進行方向と逆方向に進む。なお図８における符号
３８は振動体２との摩擦係数を向上させるための摩擦材
であり，上記回転体３の表面に貼設されている。この進
行波は，振動体２に貼設されている圧電素子１０によっ
て発生させる。That is, as shown in FIG. 8, when a traveling wave is generated in the vibrating body 2, the surface of the vibrating body 2 moves up and down while performing an elliptical motion. Therefore, the rotating body 3 that is in contact with the vibrating body 2 travels in a direction opposite to the traveling direction of the traveling wave with the elliptical motion of the surface of the vibrating body 2. Reference numeral 38 in FIG. 8 denotes a friction material for improving the coefficient of friction with the vibrating body 2, and is attached to the surface of the rotating body 3. This traveling wave is generated by the piezoelectric element 10 attached to the vibrator 2.
【０００４】具体的には，図９に示すごとく，圧電素子
１０の表側面をその円周方向に細かく区画し，その区画
毎に分極用の電極１１，１２，９１〜９４を設ける。電
極の配置は，同図において左右に位置する駆動用電極群
１１０，１２０と，上下に位置する検知用電極９１，９
２，９３，９４とに大別される。また，各電極の円周方
向の長さは，得ようとする進行波の波長をλとした場
合，駆動用電極１１，１２がλ／２，各検知用電極９
１，９２，９３はいずれもλ／４である。More specifically, as shown in FIG. 9, the front surface of the piezoelectric element 10 is finely divided in its circumferential direction, and electrodes 11, 12, 91 to 94 for polarization are provided for each division. The arrangement of the electrodes is such that drive electrode groups 110 and 120 located on the left and right in FIG.
2,93,94. When the wavelength of the traveling wave to be obtained is λ, the driving electrodes 11 and 12 are λ / 2, and the length of each electrode in the circumferential direction is λ / 2.
1, 92 and 93 are all λ / 4.
【０００５】また，各電極には，隣接する電極と逆の分
極方向となるように分極処理を施す。即ち，図９に示す
ごとく，分極方向を「＋」，「−」により示すと円周方
向に交互に「＋」と「−」を配置する。なお，圧電素子
１０の裏側面には，図１０に示すごとく，上記駆動用電
極群１１０，１２０，及び各検知用電極９１〜９４にそ
れぞれ対応する位置に，裏面電極１５，１６，９５〜９
８を設けてある。[0005] Each electrode is subjected to a polarization treatment so as to have a polarization direction opposite to that of an adjacent electrode. That is, as shown in FIG. 9, when the polarization direction is indicated by "+" and "-", "+" and "-" are alternately arranged in the circumferential direction. As shown in FIG. 10, on the back surface of the piezoelectric element 10, the back electrodes 15, 16, 95 to 9 are provided at positions corresponding to the drive electrode groups 110 and 120 and the detection electrodes 91 to 94, respectively.
8 is provided.
【０００６】そして，第１の駆動用電極群１１０の各電
極１１のみに高周波電圧を印加すると，図１１（ａ）に
示すごとき定在波Ａが発生する。一方，第２の駆動用電
極群１２０の各電極１２のみに上記高周波電圧と位相が
９０度異なる高周波電圧を印加すると，図１１（ｂ）に
示すごとき定在波Ｂが発生する。When a high-frequency voltage is applied only to each electrode 11 of the first drive electrode group 110, a standing wave A as shown in FIG. 11A is generated. On the other hand, when a high-frequency voltage having a phase different from that of the high-frequency voltage by 90 degrees is applied only to each electrode 12 of the second driving electrode group 120, a standing wave B as shown in FIG. 11B is generated.
【０００７】そして，上記２つの駆動用電極群１１０，
１２０に同時に位相が９０度ずれた上記高周波電圧をそ
れぞれ印加すると，図１２に示すごとく，定在波Ａと定
在波Ｂとが合成されて進行波Ｃが発生する。一方，上記
検知用電極９１〜９４は，いずれも電圧を印加せず，駆
動には寄与させない。そして，これら検知用電極９１〜
９４のいずれかの電圧変化を測定することにより，圧電
素子１０の振動状態をモニターすることができる。The two driving electrode groups 110,
When the high-frequency voltages whose phases are shifted by 90 degrees are simultaneously applied to 120, respectively, the standing wave A and the standing wave B are combined to generate a traveling wave C as shown in FIG. On the other hand, none of the detection electrodes 91 to 94 applies a voltage and does not contribute to driving. And these detection electrodes 91 to 91
By measuring any one of the voltage changes 94, the vibration state of the piezoelectric element 10 can be monitored.
【０００８】[0008]
【解決しようとする課題】しかしながら，上記従来の超
音波モータにおいては，次の問題がある。即ち，上記圧
電素子１０には，上記のごとく，駆動用電極１１，１
２，検知用電極９１〜９４を設ける。そして，これら各
電極１１，１２，９１〜９４に対して，隣接するものと
逆方向の分極方向を有するように分極処理を施す。However, the above conventional ultrasonic motor has the following problems. That is, as described above, the driving electrodes 11, 1
2. The detection electrodes 91 to 94 are provided. Then, a polarization process is performed on each of the electrodes 11, 12, 91 to 94 so as to have a polarization direction opposite to that of an adjacent electrode.
【０００９】この逆方向の分極処理がなされた電極間の
境界部分においては，残留応力が発生する。この残留応
力は，最も幅の狭い電極が３つ連続して配されている検
知用電極９２〜９４間において最大となる。この大きな
残留応力は，圧電素子１０にそりを発生させる原因とも
なる。また，残留応力やそりの発生は，圧電素子１０と
振動体２との間の接着性や，圧電素子１０の耐久性の低
下に影響を及ぼす。[0009] Residual stress is generated at the boundary between the electrodes subjected to the reverse polarization processing. This residual stress becomes maximum between the detecting electrodes 92 to 94 in which the three electrodes having the narrowest width are continuously arranged. This large residual stress also causes the piezoelectric element 10 to warp. Further, the occurrence of residual stress or warpage affects the adhesiveness between the piezoelectric element 10 and the vibrating body 2 and lowers the durability of the piezoelectric element 10.
【００１０】本発明は，かかる従来の問題点に鑑みてな
されたもので，圧電素子の残留応力及びそりが小さく，
耐久性に優れた超音波モータ及びその製造方法を提供し
ようとするものである。The present invention has been made in view of such a conventional problem, and has a small residual stress and warpage of a piezoelectric element.
An object of the present invention is to provide an ultrasonic motor having excellent durability and a method for manufacturing the same.
【００１１】[0011]
【課題の解決手段】請求項１の発明は，リング状の圧電
素子と，該圧電素子の表側面又は裏側面に貼設した振動
体と，該振動体に加圧当接させた回転体とを有してな
り，上記圧電素子に位相が９０度異なる２種類の高周波
電圧を印加することにより上記振動体に進行波を発生さ
せて上記回転体を摩擦駆動する超音波モータにおいて，
上記圧電素子の表側面には，円周上において１８０度の
角度を隔てて配された第１検知用電極及び第２検知用電
極を設けてなると共に，これら第１検知用電極と第２検
知用電極との間の２つの領域には，それぞれ複数の駆動
用電極に区分してなる駆動用電極群を設けてなり，ま
た，上記第１検知用電極，上記第２検知用電極及び上記
駆動用電極は，それぞれ隣接する電極と逆方向に分極処
理されており，かつ，上記圧電素子における各電極の円
周方向の長さは，振動体に発生させる進行波の波長をλ
とした場合に，上記第１検知用電極はλ／４，上記第２
検知用電極は３λ／４，上記駆動用電極はλ／２である
ことを特徴とする超音波モータにある。According to a first aspect of the present invention, there is provided a ring-shaped piezoelectric element, a vibrating body attached to a front side or a back side of the piezoelectric element, and a rotating body pressed and abutted on the vibrating body. An ultrasonic motor that frictionally drives the rotating body by generating a traveling wave in the vibrating body by applying two kinds of high-frequency voltages having phases different by 90 degrees to the piezoelectric element,
A first detection electrode and a second detection electrode are provided on the front surface of the piezoelectric element at an angle of 180 degrees on the circumference, and the first detection electrode and the second detection electrode are provided. A drive electrode group divided into a plurality of drive electrodes is provided in each of the two regions between the first and second detection electrodes, the second detection electrode, and the drive electrode. Each of the electrodes is polarized in a direction opposite to that of an adjacent electrode, and the length of each electrode in the piezoelectric element in the circumferential direction is determined by the wavelength of the traveling wave generated by the vibrator.
, The first detection electrode is λ / 4, and the second detection electrode is
The ultrasonic motor is characterized in that the detecting electrode is 3λ / 4 and the driving electrode is λ / 2.
【００１２】本発明において最も注目すべき点は，上記
圧電素子には，上記第１及び第２の２つの検知用電極を
設けこれらの円周方向の長さをそれぞれλ／４及び３λ
／４にしたこと，かつ，これら検知用電極も含めてすべ
ての電極に電極単位で分極処理を施してあることであ
る。The most notable point in the present invention is that the piezoelectric element is provided with the first and second detection electrodes, and their circumferential lengths are set to λ / 4 and 3λ, respectively.
/ 4, and all electrodes, including these detection electrodes, are subjected to polarization processing in electrode units.
【００１３】検知用電極は，超音波モータの駆動には寄
与しない電極であって，圧電素子の振動状態を電気信号
として取り出すための電極である。本発明においては，
検知用電極として，上記第１検知用電極と第２検知用電
極とを設けてある。なお，これら２つの検知用電極両方
から振動検出用の電気信号を取り出す構造にしても良い
し，いずれか一方から電気信号を取り出す構造にしても
良い。The detection electrode is an electrode which does not contribute to the driving of the ultrasonic motor, and is an electrode for extracting the vibration state of the piezoelectric element as an electric signal. In the present invention,
The first detection electrode and the second detection electrode are provided as detection electrodes. It should be noted that a structure for extracting an electric signal for vibration detection from both of these two detection electrodes or a structure for extracting an electric signal from one of them may be employed.
【００１４】次に，本発明の作用につき説明する。本発
明の超音波モータは，上記のごとく，第２検知用電極の
円周方向の長さを３λ／４という長さに設定してある。
即ち，上記圧電素子における電極は，λ／２の長さの複
数の駆動用電極と，λ／４の長さの１つの第１検知用電
極と，３λ／４の長さの１つの第２検知用電極とにより
構成されている。そのため，従来のようなλ／４の長さ
の電極が隣接するという部分は存在しない。Next, the operation of the present invention will be described. As described above, in the ultrasonic motor of the present invention, the length of the second detection electrode in the circumferential direction is set to 3λ / 4.
That is, the electrodes of the piezoelectric element include a plurality of drive electrodes having a length of λ / 2, one first detection electrode having a length of λ / 4, and one second detection electrode having a length of 3λ / 4. And a detection electrode. Therefore, there is no portion in which electrodes having a length of λ / 4 are adjacent to each other as in the related art.
【００１５】そのため，圧電素子に分極処理を施すこと
による残留応力は，従来よりも大幅に低減させることが
できる。また，残留応力の影響により生ずる圧電素子の
そりも従来よりも小さくすることができる。それ故，圧
電素子と振動体との接着性の向上，及び圧電素子の耐久
性の向上を図ることができる。特に，圧電素子に大振幅
を生じさせた場合等における割れ発生率を従来よりも大
幅に低減することができる。[0015] Therefore, the residual stress due to the polarization treatment applied to the piezoelectric element can be greatly reduced as compared with the related art. Also, the warpage of the piezoelectric element caused by the influence of the residual stress can be reduced as compared with the related art. Therefore, the adhesion between the piezoelectric element and the vibrating body can be improved, and the durability of the piezoelectric element can be improved. In particular, the rate of occurrence of cracks when a large amplitude is generated in the piezoelectric element can be significantly reduced as compared with the conventional case.
【００１６】従って，本発明によれば，圧電素子の残留
応力及びそりが小さく，耐久性に優れた超音波モータを
提供することができる。Therefore, according to the present invention, it is possible to provide an ultrasonic motor having small residual stress and warpage of the piezoelectric element and excellent durability.
【００１７】次に，請求項２の発明のように，上記圧電
素子の裏側面には，区画を設けることなく面全体に配設
してなるベタ電極を設けてあることが好ましい。即ち，
圧電素子への高周波電圧の印加は上記駆動用電極群毎に
行う。この場合，圧電素子の裏側面の電極を表側の各駆
動用電極群全体に対応して設け，その裏側面の電極ごと
にそれぞれ高周波電圧を印加することが一般的である。
しかしながら，この場合には，表側面の電極群と裏側面
の電極の円周方向の位置関係を正確に対応させることが
困難であるという問題がある。Next, as in the second aspect of the present invention, it is preferable that the back surface of the piezoelectric element is provided with a solid electrode which is disposed on the entire surface without providing a partition. That is,
The application of the high-frequency voltage to the piezoelectric element is performed for each of the driving electrode groups. In this case, generally, electrodes on the back side of the piezoelectric element are provided corresponding to the entire driving electrode group on the front side, and a high-frequency voltage is applied to each electrode on the back side.
However, in this case, there is a problem that it is difficult to accurately correspond the circumferential positional relationship between the electrode group on the front surface and the electrode on the rear surface.
【００１８】そこで，上記のごとく裏側面全体を上記ベ
タ電極として，表側面の電極配置のみによって高周波電
圧印加領域を規制するよう構成することにより，表側面
と裏側面の電極の円周方向の位置合わせを不要とするこ
とが好ましい。これにより，表裏の電極位置ずれによる
電圧印加時の不具合を解消することができる。Therefore, as described above, the entire back surface is used as the solid electrode so as to regulate the high-frequency voltage application region only by the electrode arrangement on the front surface, so that the circumferential positions of the electrodes on the front and back surfaces are adjusted. Preferably, no alignment is required. As a result, it is possible to solve the problem at the time of applying a voltage due to the displacement of the front and rear electrodes.
【００１９】また，請求項３の発明のように，上記振動
体は，上記圧電素子の裏側面に貼設してあることが好ま
しい。これにより，構造の簡単な超音波モータを得るこ
とができる。即ち，上記のごとく圧電素子の裏側面に上
記ベタ電極を配設した場合には，表側面に複数の配線を
行う必要がある。そのため，圧電素子の裏側面を振動体
に貼設して表側面を開放することにより，配線構造等を
簡単にすることができる。Further, as in the third aspect of the present invention, it is preferable that the vibrating body is attached to a back side surface of the piezoelectric element. Thereby, an ultrasonic motor having a simple structure can be obtained. That is, when the solid electrode is provided on the back surface of the piezoelectric element as described above, it is necessary to perform a plurality of wirings on the front surface. Therefore, by attaching the back side surface of the piezoelectric element to the vibrator and opening the front side surface, the wiring structure and the like can be simplified.
【００２０】また，請求項４の発明のように，上記圧電
素子の各駆動用電極群においては，隣接する上記駆動用
電極を互いに短絡させてあることが好ましい。これによ
り，駆動用電極に印加する電圧を，各駆動用電極群毎に
まとめて行うことができ，さらに配線構造を簡単にする
ことができる。In the driving electrode group of the piezoelectric element, the driving electrodes adjacent to each other are preferably short-circuited to each other. Thus, the voltages applied to the driving electrodes can be collectively performed for each driving electrode group, and the wiring structure can be further simplified.
【００２１】また，請求項５の発明のように，上記駆動
用電極の短絡は，隣接配置された各駆動用電極間を樹脂
Ａｇよりなる導電層により連結することにより行ってい
ることが好ましい。これにより，容易かつ確実に駆動用
電極の短絡を行うことができる。ここで，上記樹脂Ａｇ
とは，樹脂の中にＡｇ粉を混入させたものをいう。Further, as in the invention of claim 5, it is preferable that the short-circuiting of the driving electrodes is performed by connecting adjacent driving electrodes with a conductive layer made of resin Ag. As a result, the drive electrodes can be short-circuited easily and reliably. Here, the resin Ag
"A" means that Ag powder is mixed in a resin.
【００２２】また，請求項６の発明のように，請求項４
又は５に記載の超音波モータを製造する方法であって，
上記駆動用電極の短絡処理は，同一駆動用電極群内の駆
動用電極間を結ぶように樹脂Ａｇを塗布し，該樹脂Ａｇ
を１８０℃以下の温度により硬化して導電層を形成する
ことにより行うことを特徴とする超音波モータの製造方
法がある。即ち，上記樹脂Ａｇにより駆動用電極の短絡
を行う場合には，樹脂Ａｇを１８０℃以下の温度により
硬化させて導電層を形成する。これにより，圧電素子の
圧電性を低下させることなく駆動用電極の短絡を行うこ
とができる。Further, as in the invention of claim 6, claim 4
Or a method of manufacturing the ultrasonic motor according to 5, wherein
The short-circuit processing of the drive electrodes is performed by applying a resin Ag so as to connect the drive electrodes in the same drive electrode group, and applying the resin Ag.
By forming a conductive layer by curing at a temperature of 180 ° C. or less. That is, when the drive electrode is short-circuited by the resin Ag, the resin Ag is cured at a temperature of 180 ° C. or less to form a conductive layer. Thus, the drive electrodes can be short-circuited without lowering the piezoelectricity of the piezoelectric element.
【００２３】また，請求項７の発明のように，請求項４
に記載の超音波モータを製造する方法であって，上記駆
動用電極の短絡処理は，上記圧電素子の表面を短絡部分
を残してマスキングし，次いで，上記圧電素子の温度上
昇が１８０℃以下となるように制御しながら表面処理に
より導電層を形成することにより行うことを特徴とする
超音波モータの製造方法もある。また，請求項８の発明
のように，上記表面処理としては，例えばスパッタリン
グ処理又は蒸着処理がある。Also, as in the invention of claim 7, claim 4
2. The method of manufacturing an ultrasonic motor according to claim 1, wherein the short-circuiting of the driving electrodes is performed by masking the surface of the piezoelectric element while leaving a short-circuited portion, and then increasing the temperature of the piezoelectric element to 180 ° C. or less. There is also a method of manufacturing an ultrasonic motor, wherein the method is performed by forming a conductive layer by surface treatment while controlling so as to be as follows. Further, as in the invention of claim 8, the surface treatment includes, for example, a sputtering process or a vapor deposition process.
【００２４】この場合には，上記導電層を非常に薄い膜
にすることができ，圧電素子全体の厚みをほとんど大き
くすることなく短絡処理を施すことができる。また，上
記表面処理時において圧電素子の温度を１８０℃以下に
保持することにより，圧電素子の圧電性低下を防止する
ことができる。In this case, the conductive layer can be formed as a very thin film, and short-circuiting can be performed without increasing the thickness of the entire piezoelectric element. Further, by maintaining the temperature of the piezoelectric element at 180 ° C. or less during the surface treatment, it is possible to prevent the piezoelectricity of the piezoelectric element from lowering.
【００２５】[0025]
実施形態例１ 本発明の実施形態例にかかる超音波モータにつき，図１
〜図４を用いて説明する。本例の超音波モータ１は，図
４に示すごとく，リング状の圧電素子１０と，圧電素子
１０の表側面又は裏側面に貼設した振動体２と，振動体
２に加圧当接させた回転体３とを有してなる。そして，
圧電素子１０に位相が９０度異なる２種類の高周波電圧
を印加することにより振動体２に進行波を発生させて回
転体３を摩擦駆動するモータである。Embodiment 1 FIG. 1 shows an ultrasonic motor according to an embodiment of the present invention.
This will be described with reference to FIG. As shown in FIG. 4, the ultrasonic motor 1 of the present embodiment is configured such that a ring-shaped piezoelectric element 10, a vibrating body 2 attached to the front side or back side of the piezoelectric element 10, and a pressure contact with the vibrating body 2. Rotator 3. And
A motor that applies frictional drive to the rotating body 3 by applying a traveling wave to the vibrating body 2 by applying two types of high-frequency voltages having phases different by 90 degrees to the piezoelectric element 10.
【００２６】圧電素子１０はリング状のＰＺＴ素子より
なり，その表側面には，図１に示すごとく，円周上にお
いて１８０度の角度を隔てて配された第１検知用電極１
３及び第２検知用電極１４を設けてなる。また，これら
第１検知用電極１３と第２検知用電極１４との間の２つ
の領域には，それぞれ複数の駆動用電極に１１，１２に
区分してなる駆動用電極群１１０，１２０を設けてあ
る。The piezoelectric element 10 is composed of a ring-shaped PZT element, and has a first detection electrode 1 disposed on the front surface thereof at an angle of 180 degrees on the circumference as shown in FIG.
3 and the second detection electrode 14. In two regions between the first detection electrode 13 and the second detection electrode 14, a plurality of driving electrodes are provided with driving electrode groups 110 and 120, which are divided into 11 and 12, respectively. It is.
【００２７】また，第１検知用電極１３，第２検知用電
極１４及び駆動用電極１１，１２は，それぞれ隣接する
電極と逆分極方向に分極処理されている。かつ，圧電素
子１０における各電極の円周方向の長さは，振動体に発
生させる進行波の波長をλとした場合に，第１検知用電
極１３はλ／４，第２検知用電極１４は３λ／４，駆動
用電極１１，１２はλ／２である。The first detecting electrode 13, the second detecting electrode 14, and the driving electrodes 11, 12 are polarized in the direction opposite to that of the adjacent electrodes. When the wavelength of the traveling wave generated in the vibrating body is λ, the first detection electrode 13 is λ / 4, and the second detection electrode 14 is a circular length of each electrode in the piezoelectric element 10. Is 3λ / 4, and the driving electrodes 11 and 12 are λ / 2.
【００２８】図１には，圧電素子１０の表側面における
電極の配置状態と分極方向の分布を示してある。同図に
おいて中央上部に第１検知用電極１３，中央下部に第２
検知用電極１４を配置してあり，同図の左右にそれぞれ
８つの駆動用電極１１，１２よりなる駆動用電極群１１
０，１２０を配置してある。そして，各電極の分極方向
を「＋」，「−」により示してある。同図より知られる
ように隣接する電極はいずれも逆方向の分極がなされて
いる。FIG. 1 shows the arrangement of the electrodes on the front surface of the piezoelectric element 10 and the distribution of the polarization directions. In the figure, the first detection electrode 13 is located at the upper center and the second electrode 13 is located at the lower center.
A detection electrode 14 is disposed, and a driving electrode group 11 including eight driving electrodes 11 and 12 on the left and right sides of FIG.
0 and 120 are arranged. The polarization direction of each electrode is indicated by “+” and “−”. As is known from the figure, the adjacent electrodes are all polarized in opposite directions.
【００２９】また，図２に示すごとく，圧電素子１０の
裏側面には，駆動用電極１１０，１２０に対応する電極
１５，１６と，第１検知用電極，第２検知用電極に対応
する電極１７，１８を設けてある。なお，これらすべて
の電極は，スクリーン印刷によりＡｇを塗布し，これを
硬化させて形成してある。As shown in FIG. 2, electrodes 15 and 16 corresponding to the driving electrodes 110 and 120, and electrodes corresponding to the first and second detecting electrodes are provided on the back side surface of the piezoelectric element 10. 17 and 18 are provided. In addition, all these electrodes are formed by applying Ag by screen printing and curing it.
【００３０】また，本例の圧電素子１０は，その表側面
を振動体２に接着すると共に，裏側面の電極１５，１６
に駆動用の高周波電圧を印加するための配線を，電極１
７に振動検知用の配線を行っている（図示略）。また，
接地電極は上記振動体２からとってある。The piezoelectric element 10 of this embodiment has its front side adhered to the vibrating body 2 and the electrodes 15 and 16 on the back side.
Wiring for applying a driving high-frequency voltage to the electrode 1
7, a wiring for vibration detection is provided (not shown). Also,
The ground electrode is taken from the vibrator 2.
【００３１】また，図４に示すごとく，圧電素子１０を
接着してなる振動体２は，その内周部２１を下部ハウジ
ング５に固定してある。また，振動体２の上面には，回
転体３の外周部３１を加圧当設させてある。また，外周
部３１の当設面には，回転体３と振動体２との間の摩擦
係数を上げるための摩擦材３８を配設してある。また，
振動体２の上面には，溝２５を多数設けて回転体３との
接触面を細かく区分してある。As shown in FIG. 4, the vibrating body 2 to which the piezoelectric element 10 is adhered has its inner peripheral portion 21 fixed to the lower housing 5. An outer peripheral portion 31 of the rotating body 3 is provided on the upper surface of the vibrating body 2 under pressure. In addition, a friction material 38 for increasing a friction coefficient between the rotating body 3 and the vibrating body 2 is provided on the contact surface of the outer peripheral portion 31. Also,
A large number of grooves 25 are provided on the upper surface of the vibrating body 2 so that the contact surface with the rotating body 3 is finely divided.
【００３２】また，下部ハウジング５の中央部には，回
転軸６をベアリング５８を解して回転可能に保持してい
る。回転軸６は，下部ハウジング５の下方に突出してい
ると共に，その上部を上記回転体３の内周部に固着して
ある。また，回転軸６には，皿バネ６６を配設してあ
り，これにより回転軸３を振動体２に向けて加圧してあ
る。また，下部ハウジング５には，図３，図４に示すご
とく，カップ状の上部ケース７を被せてある。In the center of the lower housing 5, the rotating shaft 6 is rotatably held by a bearing 58. The rotating shaft 6 protrudes below the lower housing 5 and has an upper portion fixed to the inner peripheral portion of the rotating body 3. Further, a disc spring 66 is provided on the rotating shaft 6, whereby the rotating shaft 3 is pressed toward the vibrating body 2. The lower housing 5 is covered with a cup-shaped upper case 7, as shown in FIGS.
【００３３】そして，このような構成の超音波モータ１
においては，従来例にも示したごとく，各駆動用電極群
１１０，１２０に位相が９０度異なる高周波電圧を印加
することにより，振動体２に進行波Ｃが発生し（図１
２），これにより，回転体３が摩擦駆動される。Then, the ultrasonic motor 1 having such a configuration
In this case, as shown in the conventional example, a traveling wave C is generated in the vibrating body 2 by applying a high-frequency voltage having a phase difference of 90 degrees to each of the driving electrode groups 110 and 120 (FIG. 1).
2) Due to this, the rotating body 3 is driven by friction.
【００３４】次に，本例の作用につき説明する。本例の
超音波モータ１における，第２検知用電極１４の円周方
向の長さは，３λ／４という長さに設定してある。即
ち，圧電素子１０における電極は，λ／２の長さの１６
個の駆動用電極１１，１２と，λ／４の長さの１つの第
１検知用電極１３と，３λ／４の長さの１つの第２検知
用電極１４とにより構成されている。そのため，従来の
ようなλ／４の長さの電極が隣接するという部分は存在
しない。Next, the operation of this embodiment will be described. The circumferential length of the second detection electrode 14 in the ultrasonic motor 1 of the present embodiment is set to 3λ / 4. That is, the electrode of the piezoelectric element 10 has a length of 16
It is composed of driving electrodes 11 and 12, one first detecting electrode 13 having a length of λ / 4, and one second detecting electrode 14 having a length of 3λ / 4. Therefore, there is no portion in which electrodes having a length of λ / 4 are adjacent to each other as in the related art.
【００３５】そのため，圧電素子１０に分極処理を施す
ことによる残留応力は，従来よりも小さく，圧電素子１
０のそりも従来よりも小さくなる。それ故，圧電素子１
０と振動体２との接着性の向上，及び圧電素子の耐久性
の向上を図ることができる。For this reason, the residual stress due to the polarization treatment applied to the piezoelectric element 10 is smaller than in the prior art.
The warp of 0 is also smaller than before. Therefore, the piezoelectric element 1
It is possible to improve the adhesiveness between the vibration element 2 and the piezoelectric element 2 and the durability of the piezoelectric element.
【００３６】実施形態例２ 本例においては，実施形態例１の超音波モータ１（本発
明品）の耐久性の向上効果及び圧電素子１０のそり減少
効果を定量的に求めるべく試験を行った。また，比較の
ため，従来例に示した圧電体９０（図９，図１０）を用
いると共に，その他は実施形態例１と同様にした超音波
モータ（比較品）を準備し，同様に試験した。Embodiment 2 In this embodiment, a test was conducted to quantitatively determine the effect of improving the durability of the ultrasonic motor 1 (product of the present invention) of Embodiment 1 and the effect of reducing the warpage of the piezoelectric element 10. . For comparison, an ultrasonic motor (comparative product) was prepared using the same piezoelectric body 90 (FIGS. 9 and 10) shown in the conventional example as in the first embodiment, and the same test was conducted. .
【００３７】まず，圧電体１０，９０を分極処理した後
のそり量を測定した。ここで，そり量とは，圧電体１
０，９０（ＰＺＴ素子）を鉛直方向に対して垂直な平面
上に置いた場合の，ＰＺＴ素子の内周端と外周端との落
差をいう。測定結果を表１に示す。表１より知られるご
とく，本発明品における圧電素子１０は，従来よりも大
幅にそりが低減されていることが分かる。First, the amount of warpage of the piezoelectric bodies 10 and 90 after the polarization treatment was measured. Here, the amount of warpage means the piezoelectric body 1
The drop between the inner and outer peripheral ends of the PZT element when 0, 90 (PZT element) is placed on a plane perpendicular to the vertical direction. Table 1 shows the measurement results. As can be seen from Table 1, the warpage of the piezoelectric element 10 of the present invention is significantly reduced as compared with the conventional one.
【００３８】[0038]
【表１】 [Table 1]
【００３９】次に，本発明品としての超音波モータ１と
比較品としての超音波モータ９との疲労寿命試験を行っ
た。試験は，周囲温度２５±５℃にて圧電素子に２１０
Ｖｒｍｓの電圧を印加して行った。そして，３秒間のモ
ータ正転，１２秒間の停止，３秒間のモータ逆転，１２
秒間の停止を順次行う３０秒のサイクルを１回とし，こ
のサイクルを続けることができた回数により寿命を判断
した。その結果を表１に示す。表１より知られるごと
く，本発明品の寿命は比較品の１０倍以上の寿命が得ら
れることが分かる。Next, a fatigue life test was performed on the ultrasonic motor 1 as the product of the present invention and the ultrasonic motor 9 as the comparative product. The test was performed on the piezoelectric element at an ambient temperature of 25 ± 5 ° C.
The test was performed by applying a voltage of Vrms. Then, the motor rotates forward for 3 seconds, stops for 12 seconds, reverses the motor for 3 seconds,
The cycle of 30 seconds for sequentially stopping for one second was defined as one, and the life was determined based on the number of times the cycle could be continued. Table 1 shows the results. As can be seen from Table 1, the life of the product of the present invention is 10 times or more that of the comparative product.
【００４０】実施形態例３ 本例は，図６に示すごとく，実施形態例１における圧電
素子１０の裏面側の電極パターンを，区画を設けること
なく面全体に配設してなるベタ電極１９に代えた例であ
る。また，図５に示すごとく，圧電素子１０の表側面の
駆動用電極１１，１２は，それぞれの駆動用電極群１１
０，１２０内において樹脂Ａｇよりなる導電層８により
短絡させた。Embodiment 3 In this embodiment, as shown in FIG. 6, the electrode pattern on the back surface side of the piezoelectric element 10 in Embodiment 1 is applied to a solid electrode 19 which is disposed on the entire surface without providing a partition. This is a modified example. As shown in FIG. 5, the driving electrodes 11 and 12 on the front surface of the piezoelectric element 10 are
A short circuit was caused by the conductive layer 8 made of resin Ag in the inside of the metal layers 0 and 120.
【００４１】また，本例における圧電素子１０と振動体
２との接着は，図７に示すごとく，圧電素子１０の裏側
面１０２を振動体２に接着剤により接着した。そして，
駆動用の高周波電圧印加用の配線は各駆動用電極群１１
０，１２０に，振動検出用の配線は検知用電極１３に，
接地電極への配線は振動体２にそれぞれ行った（図示
略）。Further, as shown in FIG. 7, the back surface 102 of the piezoelectric element 10 was bonded to the vibrating body 2 with an adhesive, as shown in FIG. And
The wiring for applying the driving high-frequency voltage is provided by each of the driving electrode groups 11.
0, 120, the wiring for vibration detection is on the detection electrode 13,
Wiring to the ground electrode was performed on each of the vibrators 2 (not shown).
【００４２】また，上記駆動用電極１１，１２の短絡
は，同一駆動用電極群内の駆動用電極間を結ぶように樹
脂Ａｇをスクリーン印刷により塗布し，その樹脂Ａｇを
１８０℃以下の温度により硬化させて導電層８を形成す
ることにより行った。その他は実施形態例１と同様であ
る。The short-circuit between the driving electrodes 11 and 12 is performed by applying resin Ag by screen printing so as to connect the driving electrodes in the same driving electrode group, and applying the resin Ag at a temperature of 180 ° C. or less. The curing was performed by forming the conductive layer 8. Others are the same as the first embodiment.
【００４３】本例の場合には，圧電素子１０の表裏の電
極形成位置を厳密に位置合わせする必要がない。そし
て，上記駆動用電極群１１０，１２０ごとへの高周波電
圧の印加は，上記短絡した各駆動用電極群１１０，１２
０から容易に行うことができる。そのため，裏側面に設
けた電極毎にそれぞれ高周波電圧を印加する場合におけ
る，表裏の電極ずれによる不具合の発生を防止すること
ができる。In the case of the present embodiment, it is not necessary to strictly position the electrode formation positions on the front and back of the piezoelectric element 10. The application of the high-frequency voltage to each of the driving electrode groups 110 and 120 depends on the short-circuited driving electrode groups 110 and 12.
It can be easily done from zero. Therefore, when applying a high-frequency voltage to each of the electrodes provided on the back side surface, it is possible to prevent the occurrence of a problem due to the displacement of the front and back electrodes.
【００４４】また，上記駆動用電極１１，１２の短絡
は，電極１１，１２の導電材質と同じ樹脂Ａｇよりなる
導電層８により行っている。そのため，導電層８による
短絡構造は，非常に密着性に優れ，かつ導電性の優れた
ものとなる。それ故，耐久性等を低下させることなく上
記効果を発揮させることができる。その他は実施形態例
１と同様の効果が得られる。The drive electrodes 11 and 12 are short-circuited by the conductive layer 8 made of the same resin Ag as the conductive material of the electrodes 11 and 12. Therefore, the short-circuit structure using the conductive layer 8 has very excellent adhesion and excellent conductivity. Therefore, the above effects can be exerted without lowering the durability and the like. The other effects are the same as those of the first embodiment.
【００４５】なお，本例においては，上記駆動用電極の
短絡を樹脂Ａｇの塗布，硬化により行ったが，これに代
えて，スパッタリング，蒸着等の表面処理によりＡｇ等
の薄膜よりなる導電層を形成して行うこともできる。In this embodiment, the drive electrodes are short-circuited by applying and curing resin Ag. Alternatively, a conductive layer made of a thin film of Ag or the like may be formed by surface treatment such as sputtering or vapor deposition. It can also be formed.
【図１】実施形態例１における，圧電素子の表側面にお
ける電極配置を示す説明図。FIG. 1 is an explanatory diagram showing an electrode arrangement on a front surface of a piezoelectric element in a first embodiment.
【図２】実施形態例１における，圧電素子の裏側面にお
ける電極は位置を示す説明図。FIG. 2 is an explanatory view showing positions of electrodes on a back surface of a piezoelectric element in the first embodiment.
【図３】実施形態例１の超音波モータの正面図。FIG. 3 is a front view of the ultrasonic motor according to the first embodiment.
【図４】実施形態例１の超音波モータの一部切り欠き断
面図。FIG. 4 is a partially cutaway sectional view of the ultrasonic motor according to the first embodiment.
【図５】実施形態例３における，圧電素子の表側面にお
ける電極配置を示す説明図。FIG. 5 is an explanatory view showing an electrode arrangement on a front surface of a piezoelectric element according to a third embodiment.
【図６】実施形態例３における，圧電素子の裏側面にお
ける電極は位置を示す説明図。FIG. 6 is an explanatory view showing positions of electrodes on a back side surface of a piezoelectric element in a third embodiment.
【図７】実施形態例３における，振動体を貼設した圧電
素子の正面図。FIG. 7 is a front view of a piezoelectric element to which a vibrating body is attached according to a third embodiment.
【図８】超音波モータの駆動原理を示す説明図。FIG. 8 is an explanatory diagram showing a driving principle of the ultrasonic motor.
【図９】従来例における，圧電素子の表側面における電
極配置を示す説明図。FIG. 9 is an explanatory view showing the arrangement of electrodes on the front surface of a piezoelectric element in a conventional example.
【図１０】従来例における，圧電素子の裏側面における
電極は位置を示す説明図。FIG. 10 is an explanatory diagram showing positions of electrodes on a back side surface of a piezoelectric element in a conventional example.
【図１１】従来例における，個々の駆動用電極群への通
電によって発生する位相の異なる固定波を示す説明図。FIG. 11 is an explanatory view showing fixed waves having different phases generated by energizing individual drive electrode groups in a conventional example.
【図１２】従来例における，２つの固定波が合成された
移動波を示す説明図。FIG. 12 is an explanatory diagram showing a moving wave in which two fixed waves are combined in a conventional example.
１．．．超音波モータ， １０．．．圧電素子， １１，１２．．．駆動用電極， １１０，１２０．．．駆動用電極群， １３．．．第１検知用電極， １４．．．第２検知用電極， ２．．．振動体， ３．．．回転体， 1. . . Ultrasonic motor, 10. . . Piezoelectric element, 11,12. . . Driving electrode, 110, 120. . . 12. drive electrode group; . . 13. first detection electrode; . . 1. second detection electrode; . . Vibrator, 3. . . Rotating body,
Claims (8)
側面又は裏側面に貼設した振動体と，該振動体に加圧当
接させた回転体とを有してなり，上記圧電素子に位相が
９０度異なる２種類の高周波電圧を印加することにより
上記振動体に進行波を発生させて上記回転体を摩擦駆動
する超音波モータにおいて，上記圧電素子の表側面に
は，円周上において１８０度の角度を隔てて配された第
１検知用電極及び第２検知用電極を設けてなると共に，
これら第１検知用電極と第２検知用電極との間の２つの
領域には，それぞれ複数の駆動用電極に区分してなる駆
動用電極群を設けてなり，また，上記第１検知用電極，
上記第２検知用電極及び上記駆動用電極は，それぞれ隣
接する電極と逆方向に分極処理されており，かつ，上記
圧電素子における各電極の円周方向の長さは，振動体に
発生させる進行波の波長をλとした場合に，上記第１検
知用電極はλ／４，上記第２検知用電極は３λ／４，上
記駆動用電極はλ／２であることを特徴とする超音波モ
ータ。1. A piezoelectric device comprising: a ring-shaped piezoelectric element; a vibrating body attached to a front side or a back side of the piezoelectric element; and a rotating body pressed against the vibrating body. In an ultrasonic motor in which a traveling wave is generated in the vibrating body by applying two kinds of high-frequency voltages having phases different by 90 degrees to the element and the rotating body is frictionally driven, a circumferential surface is provided on a surface of the piezoelectric element. A first detection electrode and a second detection electrode disposed at an angle of 180 degrees on the upper side;
A drive electrode group divided into a plurality of drive electrodes is provided in each of the two regions between the first detection electrode and the second detection electrode. ,
The second detecting electrode and the driving electrode are polarized in a direction opposite to that of an adjacent electrode, and the length of each electrode in the piezoelectric element in the circumferential direction is equal to the length of the electrode generated by the vibrator. Where the wavelength of the wave is λ, the first detection electrode is λ / 4, the second detection electrode is 3λ / 4, and the driving electrode is λ / 2, .
面には，区画を設けることなく面全体に配設してなるベ
タ電極を設けてあることを特徴とする超音波モータ。2. The ultrasonic motor according to claim 1, wherein a solid electrode is provided on the rear side surface of the piezoelectric element without providing a partition, over the entire surface.
圧電素子の裏側面に貼設してあることを特徴とする超音
波モータ。3. The ultrasonic motor according to claim 2, wherein the vibrating body is attached to a back surface of the piezoelectric element.
の各駆動用電極群においては，隣接する上記駆動用電極
を互いに短絡させてあることを特徴とする超音波モー
タ。4. The ultrasonic motor according to claim 2, wherein adjacent driving electrodes are short-circuited in each driving electrode group of the piezoelectric element.
絡は，隣接配置された各駆動用電極間を樹脂Ａｇよりな
る導電層により連結することにより行っていることを特
徴とする超音波モータ。5. The ultrasonic motor according to claim 4, wherein the driving electrodes are short-circuited by connecting adjacent driving electrodes by a conductive layer made of resin Ag. .
製造する方法であって，上記駆動用電極の短絡処理は，
同一駆動用電極群内の駆動用電極間を結ぶように樹脂Ａ
ｇを塗布し，該樹脂Ａｇを１８０℃以下の温度により硬
化して導電層を形成することにより行うことを特徴とす
る超音波モータの製造方法。6. The method of manufacturing an ultrasonic motor according to claim 4, wherein the short-circuiting of the driving electrode is performed by:
Resin A so as to connect between the drive electrodes in the same drive electrode group
a method of manufacturing an ultrasonic motor, wherein the method is performed by applying g, and curing the resin Ag at a temperature of 180 ° C. or less to form a conductive layer.
る方法であって，上記駆動用電極の短絡処理は，上記圧
電素子の表面を短絡部分を残してマスキングし，次い
で，上記圧電素子の温度上昇が１８０℃以下となるよう
に制御しながら表面処理により導電層を形成することに
より行うことを特徴とする超音波モータの製造方法。7. The method for manufacturing an ultrasonic motor according to claim 4, wherein the short-circuiting of the driving electrode is performed by masking a surface of the piezoelectric element while leaving a short-circuited portion. Forming a conductive layer by surface treatment while controlling the temperature rise to 180 ° C. or less.
ッタリング処理又は蒸着処理であることを特徴とする超
音波モータの製造方法。8. The method for manufacturing an ultrasonic motor according to claim 7, wherein said surface treatment is a sputtering treatment or a vapor deposition treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9293470A JPH11122957A (en) | 1997-10-08 | 1997-10-08 | Ultrasonic motor and manufacture thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9293470A JPH11122957A (en) | 1997-10-08 | 1997-10-08 | Ultrasonic motor and manufacture thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11122957A true JPH11122957A (en) | 1999-04-30 |
Family
ID=17795172
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9293470A Pending JPH11122957A (en) | 1997-10-08 | 1997-10-08 | Ultrasonic motor and manufacture thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11122957A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006174618A (en) * | 2004-12-16 | 2006-06-29 | Kyocera Corp | Piezoelectric actuator and liquid discharging apparatus |
| JP2013034366A (en) * | 2011-06-27 | 2013-02-14 | Canon Inc | Piezoelectric elements, stators for oscillatory wave motors, oscillatory wave motors, driving control systems, optical apparatus, and method of manufacturing stators for oscillatory wave motors |
-
1997
- 1997-10-08 JP JP9293470A patent/JPH11122957A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006174618A (en) * | 2004-12-16 | 2006-06-29 | Kyocera Corp | Piezoelectric actuator and liquid discharging apparatus |
| JP4594060B2 (en) * | 2004-12-16 | 2010-12-08 | 京セラ株式会社 | Liquid ejection device |
| JP2013034366A (en) * | 2011-06-27 | 2013-02-14 | Canon Inc | Piezoelectric elements, stators for oscillatory wave motors, oscillatory wave motors, driving control systems, optical apparatus, and method of manufacturing stators for oscillatory wave motors |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH08213664A (en) | Multilayered ceramics piezoelectric element | |
| JPS61144565A (en) | High-polymer piezo-electric type ultrasonic probe | |
| JP4026885B2 (en) | Piezoelectric element and vibration type driving device | |
| CN101707445B (en) | Sheet and dual traveling wave type rotary ultrasonic motor and control method thereof | |
| KR910003672B1 (en) | Ultrasonic motor | |
| JPH11122957A (en) | Ultrasonic motor and manufacture thereof | |
| CN103368457A (en) | Thin-plate-type rotating ultrasonic motor | |
| JP2002142473A (en) | Vibration wave driver and apparatus using vibration wave driver | |
| JPS60183981A (en) | Supersonic wave motor | |
| JPH0650949B2 (en) | Method for manufacturing piezoelectric actuator | |
| JPS63257474A (en) | Ultrasonic motor | |
| JPS6026476A (en) | Piezoelectric motor | |
| JP2585574B2 (en) | Ultrasonic drive using a ring-shaped piezoelectric vibrator | |
| JP4731737B2 (en) | Vibration wave motor | |
| JPH09223825A (en) | Piezoelectric application element | |
| JP4341227B2 (en) | Drive device and equipment using the same | |
| JP2601659B2 (en) | Ultrasonic drive | |
| JP3089324B2 (en) | Ultrasonic motor | |
| JP2002369556A (en) | Electrical-mechanical energy conversion element and vibration wave drive apparatus | |
| JP3161028B2 (en) | Ultrasonic motor | |
| JPS6353985A (en) | Manufacture of ultrasonic driving body | |
| JPH03243180A (en) | Oscillation wave motor | |
| JPH0628951Y2 (en) | Piezoelectric actuator | |
| JP2537947B2 (en) | Ultrasonic motor | |
| JPS63171174A (en) | Ultrasonic motor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050112 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050208 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20050621 |