JPH06225550A - Ultrasonic motor - Google Patents
Ultrasonic motorInfo
- Publication number
- JPH06225550A JPH06225550A JP50A JP1187393A JPH06225550A JP H06225550 A JPH06225550 A JP H06225550A JP 50 A JP50 A JP 50A JP 1187393 A JP1187393 A JP 1187393A JP H06225550 A JPH06225550 A JP H06225550A
- Authority
- JP
- Japan
- Prior art keywords
- ultrasonic motor
- rotor
- envelope
- grooves
- stator
- 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.)
- Granted
Links
- 230000008859 change Effects 0.000 claims abstract description 31
- 238000001514 detection method Methods 0.000 claims abstract description 14
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 9
- 238000005259 measurement Methods 0.000 description 7
- 238000006073 displacement reaction Methods 0.000 description 6
- 239000002783 friction material Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Landscapes
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、圧電、磁歪等の電気
−機械変換による超音波モータの位置情報の検知と制御
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detection and control of position information of an ultrasonic motor by electromechanical conversion such as piezoelectric and magnetostriction.
【０００２】[0002]
【従来の技術】従来、超音波モータのロータの回転数、
位置等の回転情報を検知するためには磁気的、または光
学的なエンコーダ等の装置を超音波モータに付加しなけ
ればならなかった。2. Description of the Related Art Conventionally, the number of revolutions of a rotor of an ultrasonic motor,
A device such as a magnetic or optical encoder has to be added to the ultrasonic motor in order to detect rotation information such as position.
【０００３】このような課題を改善する方法として、超
音波モータに検出器を組み込んだものとして、例えば、
特開昭６２−２２１８８５号公報に、ロータに溝等の不
連続部分を設け、ステータに発生する断続的な波形歪み
を検出して、回転情報を得るものがある。As a method of improving such a problem, for example, an ultrasonic motor incorporating a detector,
Japanese Unexamined Patent Publication No. 62-221885 discloses a method in which a rotor is provided with a discontinuous portion such as a groove, and intermittent waveform distortion occurring in the stator is detected to obtain rotation information.
【０００４】[0004]
【発明が解決しようとする課題】しかし、前述したよう
に超音波モータに前記エンコーダを付加すると、超音波
モータ全体の体積が増大し、大きな組み込みスペースが
必要となり、使用範囲が限定され、超音波モータ自体の
製造工数も増大する。従って、特開昭６２−２２１８８
５号公報による従来の方法は、圧電体の駆動電極の一部
を、回転情報検出電極として使用しているため、駆動電
極の使用効率が低下するだけでなく、回転情報の精度を
上げるためには検出電極を多くしなければならず、さら
に、駆動電極の使用効率が低下するという課題があっ
た。However, when the encoder is added to the ultrasonic motor as described above, the volume of the ultrasonic motor as a whole increases, a large installation space is required, and the range of use is limited. The manufacturing man-hours of the motor itself also increase. Therefore, JP-A-62-22188
The conventional method disclosed in Japanese Patent No. 5 uses a part of the drive electrode of the piezoelectric body as a rotation information detection electrode, and therefore not only reduces the use efficiency of the drive electrode but also improves the accuracy of the rotation information. However, the number of detection electrodes must be increased, and further, the use efficiency of the drive electrodes is reduced.
【０００５】そこで、この発明の目的は、従来のこのよ
うな課題を解決するために、エンコーダ等の別付加の検
出器を設けたり、駆動電極の一部を回転情報検出用に使
用することなく、回転情報を簡易な方法で検出できる超
音波モータを提供できるようにした。Therefore, an object of the present invention is to solve the above-mentioned conventional problems without providing an additional detector such as an encoder or using a part of the drive electrode for detecting rotation information. , It has become possible to provide an ultrasonic motor that can detect rotation information by a simple method.
【０００６】[0006]
【課題を解決するための手段】上記課題を解決するため
に、この発明の超音波モータは、ロータに溝または突起
部等の不均一部を設け、ステータへ接着等で接合された
圧電素子への駆動電流の波高値の包絡線の変化を検出
し、電気的な信号処理をすることにより、ロータの回転
情報を検出できるようにした。In order to solve the above-mentioned problems, the ultrasonic motor of the present invention has a rotor having a non-uniform portion such as a groove or a projection, and a piezoelectric element bonded to the stator by adhesion or the like. The rotation information of the rotor can be detected by detecting the change in the envelope of the crest value of the drive current and performing electrical signal processing.
【０００７】その原理は、円板または円環型の進行波型
の超音波モータで、進行波を発生させるための電気−機
械変換子である圧電素子を等分割して、超音波の進行波
を、発生させると、圧電素子の分割数に応じた個数の進
行波が、ステータに発生し、進行波の振幅の変化によ
り、不均一部を設けない通常の状態でも、ステータに接
合された圧電素子へ供給している駆動電流の波高値の包
絡線に変化が生じるが、この駆動電流の波高値の包絡線
の変化は、進行波の波数の２倍と同数である。すなわち
進行波によりモータが回転すると、１回転当たり進行波
の波数の２倍と同数の駆動電流の波高値の包絡線の変化
による信号波が発生する。またステータに設けた櫛歯状
の突起部とロータの不均一部と圧電素子の分割数との関
係により、不均一部の数と同数の電流変化を生じさせ、
さらに、不均一部の数の２倍、３倍の駆動電流の波高値
の包絡線の変化を発生させることもでき、さらに駆動電
流の波高値の包絡線の変化を顕著にすることもできる。The principle is that in a traveling-wave type ultrasonic motor of a disk or annular type, a piezoelectric element, which is an electro-mechanical transducer for generating a traveling wave, is equally divided, and a traveling wave of the ultrasonic wave is generated. Then, the number of traveling waves corresponding to the number of divisions of the piezoelectric element is generated in the stator, and due to the change in the amplitude of the traveling wave, even if the non-uniform portion is not provided in the normal state, the piezoelectric wave bonded to the stator is A change occurs in the crest value envelope of the drive current supplied to the element, and the change in the crest value envelope of the drive current is the same as twice the wave number of the traveling wave. That is, when the motor is rotated by the traveling wave, a signal wave is generated due to a change in the envelope of the crest value of the driving current, which is equal to twice the wave number of the traveling wave per rotation. Also, due to the relationship between the comb-teeth-shaped protrusions provided on the stator, the non-uniform portion of the rotor, and the number of divisions of the piezoelectric element, the same number of current changes as the number of non-uniform portions are generated.
Furthermore, it is possible to generate a change in the crest value envelope of the drive current that is twice or three times the number of non-uniform portions, and it is possible to make the change in the crest value envelope of the drive current noticeable.
【０００８】[0008]
【作用】上記のように構成された超音波モータにおいて
は、ステータの圧電素子への駆動電流の変化を検出し、
フィルタ等を介して超音波モータの駆動周波数成分をと
りのぞき、アナログ、デジタル信号処理をすることによ
り、ロータの回転情報をアナログ、デジタル信号として
取り出し、別付加のエンコーダ等を設けることなく、超
音波モータおよび超音波モータを使用した機器の回転
数、速度、位置制御等が可能となる。In the ultrasonic motor configured as described above, the change of the drive current to the piezoelectric element of the stator is detected,
By removing the drive frequency component of the ultrasonic motor through a filter and performing analog and digital signal processing, the rotation information of the rotor can be extracted as analog and digital signals, and ultrasonic waves can be obtained without providing an additional encoder. It is possible to control the number of revolutions, speed, position, etc. of equipment using a motor and an ultrasonic motor.
【０００９】[0009]
【実施例】以下に、この発明の実施例を図面に基づいて
説明する。なお実施例の各図において、同様の部位には
同一の符号を付し、重複した説明は省略する。図１乃至
図８は、本発明の超音波モータの実施例を示す。図１
は、本発明の超音波モータの駆動とロータの回転情報を
得る回路をブロック的に示した説明図であり、図２は、
本発明の超音波モータの検出した信号の処理課程におけ
る信号の波形変化を示す図である。図３及び図４は、本
発明の超音波モータの駆動回路に対応した、圧電素子の
実施例を示す平面図である。図５は本発明の超音波モー
タの構造の実施例を示した縦断面図である。図６乃至図
８は、本発明の超音波モータの構造を示す斜視図であ
る。Embodiments of the present invention will be described below with reference to the drawings. In each of the drawings of the embodiments, the same parts are designated by the same reference numerals, and the duplicated description will be omitted. 1 to 8 show an embodiment of the ultrasonic motor of the present invention. Figure 1
FIG. 2 is a block diagram showing a circuit for driving the ultrasonic motor and obtaining rotation information of the rotor of the present invention, and FIG.
It is a figure which shows the waveform change of the signal in the process of the signal which the ultrasonic motor of this invention detected. 3 and 4 are plan views showing an embodiment of a piezoelectric element corresponding to the drive circuit of the ultrasonic motor of the present invention. FIG. 5 is a vertical sectional view showing an embodiment of the structure of the ultrasonic motor of the present invention. 6 to 8 are perspective views showing the structure of the ultrasonic motor of the present invention.
【００１０】図１において、超音波モータのステータ１
は振動子１ａに駆動電極１ｃ１、及び駆動電極１ｃ２を
有する圧電素子１ｂが接合され、発振回路６によりステ
ータ１の共振周波数近傍で発振された信号を２つの信号
に分岐し、一方は増幅器４により増幅し、他方は±９０
゜移相器５により正転、逆転設定に応じた±９０゜の位
相回転を与え、増幅器３により、それぞれ駆動電極１ｃ
２、駆動電極１ｃ１に駆動信号を印加し、ステータ１の
振動子１ａに進行波を発生させる。またステータ１の振
動子１ａとＧＮＤ２０間に検出抵抗７が挿入され、駆動
電流の変化を検出する。検出抵抗７の両端より検出され
た駆動電流の波形は、図２（Ａ）に示すように、ロータ
の回転による低周波信号により変調された波形となる。
図２（Ａ）の信号をバッファ増幅検波回路８で増幅、検
波、インピーダンス変換して、超音波モータの駆動周波
数成分を波高値の包絡線の成分だけにすると、図２
（Ｂ）に示す波形となり、フィルタ９を通して、回転に
よる変化分だけ、すなわち駆動電流の波高値の包絡線の
周波数成分を取り出すと図２（Ｃ）に示す波形となる。
このようにして取り出された信号を処理を行い、図２
（Ｃ）に示す波形のアナログ、または図１（Ｄ）に示す
波形の信号としてデジタル処理をし、超音波モータの位
置情報として出力する。In FIG. 1, the stator 1 of the ultrasonic motor is shown.
The piezoelectric element 1b having the drive electrode 1c1 and the drive electrode 1c2 is joined to the vibrator 1a, and the signal oscillated by the oscillation circuit 6 in the vicinity of the resonance frequency of the stator 1 is branched into two signals. Amplify, the other is ± 90
The phase shifter 5 gives a phase rotation of ± 90 ° according to the forward and reverse rotation settings, and the amplifier 3 drives the drive electrodes 1c respectively.
2. A drive signal is applied to the drive electrode 1c1 to generate a traveling wave in the vibrator 1a of the stator 1. A detection resistor 7 is inserted between the vibrator 1a of the stator 1 and the GND 20 to detect a change in drive current. The waveform of the drive current detected from both ends of the detection resistor 7 is a waveform modulated by a low frequency signal due to the rotation of the rotor, as shown in FIG. 2 (A).
When the signal of FIG. 2A is amplified, detected, and impedance-converted by the buffer amplification detection circuit 8 so that the drive frequency component of the ultrasonic motor is only the component of the crest value envelope,
The waveform shown in FIG. 2B is obtained through the filter 9, and only the change due to rotation, that is, the frequency component of the envelope of the peak value of the drive current is extracted, and the waveform shown in FIG. 2C is obtained.
The signal thus extracted is processed, and
An analog signal having a waveform shown in FIG. 1C or a signal having a waveform shown in FIG. 1D is digitally processed and output as position information of the ultrasonic motor.
【００１１】また図３及び図４は、前記本発明の超音波
モータの進行波を発生させ、回転による駆動電流変化分
を取り出すための駆動回路に対応した駆動電極１ｃ１、
駆動電極１ｃ２を有する圧電素子の平面図である。駆動
電極１ｃ１、駆動電極１ｃ２は電気角で９０゜の位相差
を有し、同一の駆動電極郡では各々の電極は交互に異極
に分極され、駆動電極１ｃ１は内周で接続し、駆動電極
１ｃ２は外周で接続され、それぞれ２つの電極群を構成
しており、駆動電極１ｃ１、駆動電極１ｃ２全体では１
２等分割されている。この各々の駆動電極に前記の駆動
信号が印加されるとステータ１には電気角で９０゜の位
相差を有する３波の進行波が励起される。Further, FIGS. 3 and 4 show a drive electrode 1c1 corresponding to a drive circuit for generating a traveling wave of the ultrasonic motor of the present invention and extracting a drive current change due to rotation.
It is a top view of a piezoelectric element which has drive electrode 1c2. The drive electrodes 1c1 and 1c2 have a phase difference of 90 ° in terms of electrical angle, and in the same drive electrode group, the electrodes are alternately polarized to different polarities, and the drive electrodes 1c1 are connected on the inner circumference. 1c2 is connected on the outer circumference and constitutes two electrode groups, and the drive electrode 1c1 and the drive electrode 1c2 as a whole are 1
It is divided into two equal parts. When the drive signal is applied to each drive electrode, three traveling waves having a phase difference of 90 ° in electrical angle are excited in the stator 1.
【００１２】図５は本発明の超音波モータの構成を示す
縦断面図の例であり、図６は構成例を示す模式図であ
る。駆動用の圧電素子１ｂを接合されたステータ１は駆
動回路により共振周波数近傍で進行波を発生し、進行波
により摩擦材１１を通して摩擦力によりロータ体１２を
回転させる。ロータ体１２には図６に示すように溝部１
２ａを設けてある。加圧機構１３は加圧力を発生、調整
して摩擦力を調整する。図５ではコイルばねの実施例、
図６には板ばねの実施例を示す。また中心軸１５は超音
波モータの中心を構成しステータ１を固着支持し、外部
にモータを取り付けるための支持板１４に打ち込み固着
されている。FIG. 5 is an example of a vertical sectional view showing the structure of the ultrasonic motor of the present invention, and FIG. 6 is a schematic view showing an example of the structure. The stator 1 to which the driving piezoelectric element 1b is joined generates a traveling wave near the resonance frequency by the driving circuit, and the traveling wave causes the rotor body 12 to rotate by the frictional force through the friction material 11. As shown in FIG. 6, the groove portion 1 is formed on the rotor body 12.
2a is provided. The pressure mechanism 13 generates and adjusts a pressing force to adjust the frictional force. In FIG. 5, an embodiment of a coil spring,
FIG. 6 shows an embodiment of the leaf spring. Further, the central shaft 15 constitutes the center of the ultrasonic motor, fixes and supports the stator 1, and is driven and fixed to a support plate 14 for mounting the motor to the outside.
【００１３】また図７及び図８には本発明の超音波モー
タの実施例のロータ１２を示す。図７は、不均一部１２
ａが溝の実施例を示し、図８は不均一部１２ａが凸部の
実施例を示す。ここに、溝部および凸部の幅Ｂはそれ以
外の部分の幅Ａよりも狭い。また図７に示す溝の実施例
では、摩擦材１１まで溝部となっているが、図８に示す
凸部の実施例では摩擦材１１は均一である。7 and 8 show a rotor 12 of an ultrasonic motor according to an embodiment of the present invention. FIG. 7 shows the uneven portion 12
FIG. 8 shows an example in which a is a groove, and FIG. 8 shows an example in which the uneven portion 12a is a convex portion. Here, the width B of the groove portion and the convex portion is narrower than the width A of the other portion. Further, in the embodiment of the groove shown in FIG. 7, the friction material 11 is a groove portion, but in the embodiment of the convex portion shown in FIG. 8, the friction material 11 is uniform.
【００１４】次に信号の取り出し方法について説明す
る。図１に示す本発明の超音波モータのの構成により超
音波モータを回転させ、検出抵抗７により超音波モータ
に流れる駆動電流波形を観察すると、ロータに溝等の不
均一部を設けなくても明確ではないが、電流波形の波高
値の包絡線の変化が、１回転当たり６個発生している。
これはステータに発生している進行波の波数の２倍であ
る。Next, a method of extracting a signal will be described. When the ultrasonic motor having the configuration of the ultrasonic motor of the present invention shown in FIG. 1 is rotated and the drive current waveform flowing through the ultrasonic motor by the detection resistor 7 is observed, it is possible to provide a rotor with no nonuniform portion such as grooves. Although not clear, six changes in the envelope of the peak value of the current waveform occur per rotation.
This is twice the wave number of the traveling wave generated in the stator.
【００１５】図９は、この様子を示したものであり、ロ
ータに溝等の不均一部を設けずにロータの回転の状態を
観察するために、非常に小さなアルミ粘着テープ３枚を
ロータに１２０゜間隔で貼付して、反射型の光センサー
によりロータの回転状態と、駆動電流波形の関係を、観
察した結果を示す。FIG. 9 shows this state. In order to observe the rotating state of the rotor without providing the rotor with uneven portions such as grooves, three very small aluminum adhesive tapes are attached to the rotor. The results obtained by observing the relationship between the rotation state of the rotor and the drive current waveform by using a reflection type optical sensor, which are attached at 120 ° intervals, are shown.
【００１６】図１０乃至図１４は、ロータに溝による不
均一部を設け、光の反射による変位計で溝部の数を変え
て溝部の位置を測定し、電流波形と比較観察した結果を
示す。図１５は、以上の結果と溝部を１、３、４本にし
た場合の結果を加えて一覧表にしたものである図９と図
１０乃至図１４を比較すると、ロータに溝による不均一
部を設けると、電流波形の波高値の包絡線の変化が強調
されることが明確である。FIGS. 10 to 14 show the results of comparison of the current waveform with the current waveform by measuring the position of the groove portions by changing the number of the groove portions with a displacement meter that reflects light and changing the number of the groove portions in the rotor. FIG. 15 is a table in which the above results and the results when the number of grooves is 1, 3, and 4 are added, and FIG. 9 is compared with FIG. 10 to FIG. It is clear that the change of the envelope of the peak value of the current waveform is emphasized by providing.
【００１７】さらに図１５の表より、ロータの溝部の
数、６、１２、１８としたとき駆動電流の波高値の包絡
線の波形は、ロータ１回転あたりそれぞれ６、１２、１
８個の変化を発生し、この様子を図１０乃至図１２に示
す。一般的には、ロータに設けた溝等の不均一部の数
を、進行波の波数の２＊Ｎ倍にとると進行波の２＊Ｎ倍
の電流波形の波高値の包絡線の変化が生じる。ここに、
Ｎは１以上の正の整数でＮ＝１、２、３、．．．であ
る。すなわち、溝等の不均一部の数と同数の電流波形の
波高値の包絡線の変化が生じることになる。Further, from the table of FIG. 15, when the number of groove portions of the rotor is 6, 12, and 18, the waveforms of the envelope curves of the peak value of the drive current are 6, 12, and 1 per rotation of the rotor, respectively.
Eight changes are generated, and this state is shown in FIGS. Generally, when the number of non-uniform portions such as grooves provided in the rotor is set to 2 * N times the wave number of the traveling wave, the change in the crest value envelope of the current waveform 2 * N times the traveling wave occurs. Occurs. here,
N is a positive integer of 1 or more and N = 1, 2, 3 ,. ． ． Is. That is, the same number of changes in the crest value envelope of the current waveform as the number of non-uniform portions such as grooves occur.
【００１８】さらに、ロータの溝部の数を１５本にした
ときに、電流波形の波高値の包絡線の変化がロータ１回
転当たり３０個発生している。この実験結果を図１４に
示す。これを一般式にすれば、ロータの溝等の不均一部
の数を、進行波の波数をｍとするとｍ＊（Ｎ＋１）にと
ると、２＊ｍ＊（Ｎ＋１）の電流波形の波高値の包絡線
の変化が生じる。Further, when the number of groove portions of the rotor is set to 15, there are 30 changes in the envelope curve of the crest value of the current waveform per rotation of the rotor. The results of this experiment are shown in FIG. Using this as a general formula, if the number of non-uniform portions such as the grooves of the rotor is m * (N + 1) where m is the wave number of the traveling wave, the peak value of the current waveform is 2 * m * (N + 1). A change in the envelope of occurs.
【００１９】すなわち、これは溝等の不均一部の数の２
倍の電流波形の波高値の包絡線の変化が生じることにな
る。ただし、ｍ＊（Ｎ＋１）が２＊ｍの公倍数になって
いる時は、ｍ＊（Ｎ＋１）の電流波形の波高値の包絡線
の変化しか生じない。すなわち前記の溝部の数と同数の
電流波形の波高値の包絡線の変化しか生じないことにな
る。That is, this is 2 which is the number of non-uniform portions such as grooves.
A change in the envelope of the peak value of the doubled current waveform will occur. However, when m * (N + 1) is a common multiple of 2 * m, only the change in the envelope of the peak value of the current waveform of m * (N + 1) occurs. That is, only the number of changes in the envelope of the crest value of the current waveform is the same as the number of the groove portions.
【００２０】同様に、ロータの溝部の数を１０本にした
ときに、電流波形の波高値の包絡線の変化がロータ１回
転当たり３０個発生している。この実験結果を図１３に
示す。これを一般式にすれば、ロータの溝等の不均一部
の数を、２＊ｍ＊（Ｎ＋２）／３倍にとると、２＊ｍ＊
（Ｎ＋２）倍の電流波形の波高値の包絡線の変化が生じ
る。すなわち、これは溝等の不均一部の数の３倍の電流
波形の波高値の包絡線の変化が生じることになる。ただ
し、２＊ｍ＊（Ｎ＋２）／３は、ロータの溝等の不均一
部の数であるから、整数でなければなず、２＊ｍの公倍
数になっている時は、２＊ｍ＊（Ｎ＋２）／３の電流波
形の波高値の包絡線の変化しか生じない。すなわち、上
述の条件を満足する場合には、ロータの溝等の不均一部
の数の２倍、３倍の電流波形の波高値の包絡線の変化を
生じさせることができる。なお、ＮはＮ＝１、２、
３、．．．．の整数である。Similarly, when the number of groove portions of the rotor is 10, there are 30 changes in the envelope of the crest value of the current waveform per rotor revolution. The result of this experiment is shown in FIG. Using this as a general formula, if the number of non-uniform portions such as the grooves of the rotor is taken as 2 * m * (N + 2) / 3 times, then 2 * m *
A change occurs in the envelope of the peak value of the current waveform that is (N + 2) times. That is, this results in a change in the envelope of the crest value of the current waveform that is three times the number of non-uniform portions such as grooves. However, since 2 * m * (N + 2) / 3 is the number of non-uniform portions such as the grooves of the rotor, it must be an integer, and when it is a common multiple of 2 * m, it is 2 * m *. Only the change in the crest value envelope of the (N + 2) / 3 current waveform occurs. That is, when the above conditions are satisfied, it is possible to cause a change in the envelope of the peak value of the current waveform that is twice or three times the number of non-uniform portions such as the grooves of the rotor. Note that N is N = 1, 2,
3 ,. ． ． ． Is an integer.
【００２１】エンコーダとして評価したとき、１回転当
たりの信号数が多いほど分解能が高くなるので、溝等の
不均一部の数を増やせば良いが、加工工数が増加する、
強度が弱くなる、さらに溝の数を増加させるとモータの
トルクが減少する等の課題が発生する。When evaluated as an encoder, the higher the number of signals per rotation, the higher the resolution. Therefore, it is sufficient to increase the number of non-uniform portions such as grooves, but the processing man-hour increases.
If the strength becomes weaker and the number of grooves is further increased, problems such as a decrease in motor torque occur.
【００２２】またステータに設けた突起部との関係であ
るが、図１５により明らかなようにステータ１に接合さ
れた圧電素子１ｂの駆動電極１ｃ１、駆動電極１ｃ２の
分割数１２の公約数になっていない分割数２２、２５本
では、上記の溝数の１、２、３倍の電流波形の波高値の
包絡線の変化は生じず、進行波の２倍の変化、すなわち
６個の電流波形の波高値の包絡線の変化しか生じない。
これより、ステータに設けた突起部の数は進行波の波数
をｍとすれば、ｍ＊４＊Ｎ（Ｎ＝１、２、３、．．．）
でなければならない。Regarding the relationship with the protrusions provided on the stator, as is clear from FIG. 15, the driving electrode 1c1 and the driving electrode 1c2 of the piezoelectric element 1b joined to the stator 1 is a common divisor of the number of divisions 12. When the number of divisions is 22 and 25, the envelope of the peak value of the current waveform that is 1, 2, or 3 times the number of grooves does not change, but does not change twice that of the traveling wave, that is, 6 current waveforms. Only changes in the envelope of the peak value of
From this, the number of protrusions provided on the stator is m * 4 * N (N = 1, 2, 3, ...) When the wave number of the traveling wave is m.
Must.
【００２３】また、溝等の不均一部の数をできるだけ少
なくして、１回転当たりの信号数を増加させることが望
ましい。従って、ロータに設けた溝部等の不均一部の
２、３倍の電流変化による信号を発生させることが有利
となる。本実施例のｍ＝３、ステータの突起部の数が２
４の場合は、溝部の数が１０本で信号波形３０程度がエ
ンコーダとして特性的にも、経済的にも適している。Further, it is desirable to increase the number of signals per rotation by reducing the number of non-uniform portions such as grooves. Therefore, it is advantageous to generate a signal due to a current change that is two or three times as large as that of a nonuniform portion such as a groove portion provided in the rotor. In this embodiment, m = 3, and the number of protrusions of the stator is 2.
In the case of 4, the number of grooves is 10 and the signal waveform of about 30 is suitable as an encoder both in terms of characteristics and economically.
【００２４】同様にして、圧電素子の分割数、ステータ
の突起部の数、溝等の不均一部の数を適正に選べば、溝
等の不均一部の数の５倍、７倍等素数倍の駆動電流の波
高値の包絡線波形の変化を生ぜしめる可能性もある。一
般式としては、溝等の不均一部の数の１個当たりｋ倍の
駆動電流の波高値の包絡線波形の変化を生ぜしめたい場
合には、溝等の不均一部の数をＳｎとすれば Ｓｎ＝２＊ｍ＊（Ｎ＋ｋ−１）／ｋ ただし、Ｓｎは整数で Ｓｎ＞２＊ｍ またｋはＮ以下の数であって素数であり、Ｓｎがｋ以下
の場合の溝等の不均一部の数の公倍数になっている場合
には、溝等の不均一部の数の１個当たりの電流波形の波
高値の包絡線の変化は、ｋ以下の最小の公約数しか生じ
ない。Similarly, if the number of divisions of the piezoelectric element, the number of protrusions of the stator, and the number of nonuniform portions such as grooves are properly selected, the prime number is 5 times or 7 times the number of nonuniform portions such as grooves. There is also a possibility of causing a change in the envelope waveform of the peak value of the double drive current. As a general formula, when it is desired to cause a change in the envelope waveform of the peak value of the drive current that is k times the number of non-uniform portions such as grooves, the number of non-uniform portions such as grooves is set to Sn. Then Sn = 2 * m * (N + k-1) / k where Sn is an integer Sn> 2 * m Also, k is a number less than or equal to N and is a prime number, such as a groove when Sn is less than or equal to k. When it is a common multiple of the number of non-uniform portions, the change in the envelope of the peak value of the current waveform per one number of non-uniform portions such as grooves occurs only in the lowest common divisor of k or less. .
【００２５】また前述したロータに設ける不均一部を溝
部とした場合には、溝部の数を増加させるとモータのト
ルクが減少する問題が生じるが、この改善の実施例を図
１６に示す。図１６においてロータ１２には溝部１２ａ
を設けるが、ロータに接着、またはインサート成形等に
より接合された摩擦材１１には、溝部を設けない構造と
すればトルクの減少は大幅に改善され、さらに溝部の中
まで摩擦材を充填してロータと摩擦材とをインサート成
形等により一体成形をすることもできる。When the above-mentioned non-uniform portion provided on the rotor is a groove, there is a problem that the torque of the motor decreases when the number of grooves is increased. An example of this improvement is shown in FIG. In FIG. 16, the rotor 12 has a groove 12a.
However, if the friction member 11 bonded to the rotor by bonding, or joined by insert molding or the like is not provided with a groove, the reduction in torque is greatly improved. Further, the friction material is filled into the groove. It is also possible to integrally form the rotor and the friction material by insert molding or the like.
【００２６】[0026]
【発明の効果】この発明は、以上説明したように、超音
波モータのロータに溝または突起部等の不均一部を設
け、不均一部の数と、ステータに接合した圧電素子の分
割数とステータの突起部の数を適正に設定することによ
り駆動電流の波高値の包絡線の変化の数をロータに溝ま
たは突起部等の不均一部の数の１、２、３、．．．ｋ倍
（ただしｋはＮ以下の数であって素数）にすることがで
き、エンコーダ等の別付加の検出器を設けたり、駆動電
極の一部を回転情報検出用に使用することなく、超音波
モータの回転情報を簡易な方法で、高分解能に検出でき
る超音波モータを提供できるようにし、本発明の超音波
モータを使用した装置では、この回転情報により別付加
のエンコーダ等を使用することなく、回転数、位置等の
制御が可能となる。As described above, according to the present invention, the rotor of the ultrasonic motor is provided with the non-uniform portion such as the groove or the projection, and the number of the non-uniform portions and the number of divisions of the piezoelectric element joined to the stator. By properly setting the number of protrusions of the stator, the number of changes in the envelope of the peak value of the drive current can be set to 1, 2, 3 ,. ． ． It can be multiplied by k (where k is a number less than or equal to N and is a prime number), and without using an additional detector such as an encoder or using a part of the drive electrode for rotation information detection, An ultrasonic motor capable of detecting the rotation information of the ultrasonic motor by a simple method with a high resolution can be provided. In an apparatus using the ultrasonic motor of the present invention, an additional encoder or the like can be used depending on the rotation information. Instead, it becomes possible to control the number of revolutions, the position, and the like.
【図１】本発明の超音波モータの駆動およびロータの回
転情報を得る回路をブロック的に示した説明図である。FIG. 1 is an explanatory diagram showing a block diagram of a circuit for driving an ultrasonic motor and obtaining rotation information of a rotor of the present invention.
【図２】本発明の超音波モータの信号処理課程における
信号の波形変化を模式的に示した説明図である。FIG. 2 is an explanatory view schematically showing a signal waveform change in a signal processing process of the ultrasonic motor of the present invention.
【図３】本発明の超音波モータの駆動回路に対応した圧
電素子の実施例の第一の面を示す平面図である。FIG. 3 is a plan view showing a first surface of an embodiment of the piezoelectric element corresponding to the drive circuit for the ultrasonic motor of the present invention.
【図４】本発明の超音波モータの構造の駆動回路に対応
した圧電素子の実施例の第二の面を示す平面図である。FIG. 4 is a plan view showing a second surface of an embodiment of the piezoelectric element corresponding to the drive circuit of the ultrasonic motor structure of the present invention.
【図５】本発明の超音波モータの構造の実施例を示した
縦断面図である。FIG. 5 is a vertical sectional view showing an embodiment of the structure of the ultrasonic motor of the present invention.
【図６】本発明の超音波モータの構造の実施例を示す斜
視図である。FIG. 6 is a perspective view showing an embodiment of the structure of the ultrasonic motor of the present invention.
【図７】本発明の超音波モータのロータの構造の実施例
を示す斜視図である。FIG. 7 is a perspective view showing an embodiment of the structure of the rotor of the ultrasonic motor of the present invention.
【図８】本発明の超音波モータのロータの構造の実施例
を示す斜視図である。FIG. 8 is a perspective view showing an embodiment of the structure of the rotor of the ultrasonic motor of the present invention.
【図９】本発明の超音波モータの実施例のロータに溝等
の不均一部を設けずに、ロータの回転状態と駆動電流波
形の関係を示す測定結果である。FIG. 9 is a measurement result showing the relationship between the rotation state of the rotor and the drive current waveform without providing the rotor with an uneven portion such as grooves in the embodiment of the ultrasonic motor of the present invention.
【図１０】本発明の超音波モータの実施例のロータに溝
による６本の不均一部を設け、光の反射による変位計に
よるロータの回転状態と駆動電流波形とを比較観察した
測定結果である。FIG. 10 is a measurement result of comparing and observing a rotation state of the rotor and a drive current waveform by a displacement meter due to reflection of light, in which a rotor of an ultrasonic motor of the present invention is provided with six non-uniform portions due to grooves. is there.
【図１１】本発明の超音波モータの実施例のロータに溝
による１２本の不均一部を設け、光の反射による変位計
によるロータの回転状態と駆動電流波形とを比較観察し
た測定結果である。FIG. 11 is a measurement result of comparing and observing a rotating state of a rotor and a drive current waveform by a displacement meter due to reflection of light, in which a rotor of an ultrasonic motor according to an embodiment of the present invention is provided with 12 non-uniform portions due to grooves. is there.
【図１２】本発明の超音波モータの実施例のロータに溝
による１８本の不均一部を設け、光の反射による変位計
によるロータの回転状態と駆動電流波形とを比較観察し
た測定結果である。FIG. 12 is a measurement result of comparing and observing a rotating state of the rotor and a drive current waveform by a displacement meter due to reflection of light, by providing 18 non-uniform portions due to grooves in the rotor of the ultrasonic motor of the present invention. is there.
【図１３】本発明の超音波モータの実施例のロータに溝
による１０本の不均一部を設け、光の反射による変位計
によるロータの回転状態と駆動電流波形とを比較観察し
た測定結果である。FIG. 13 is a measurement result obtained by comparing and observing the rotation state of the rotor and the drive current waveform by a displacement meter due to the reflection of light, in which the rotor of the embodiment of the ultrasonic motor of the present invention is provided with ten non-uniform portions due to grooves. is there.
【図１４】本発明の超音波モータの実施例のロータに溝
による１５本の不均一部を設け、光の反射による変位計
によるロータの回転状態と駆動電流波形とを比較観察し
た測定結果である。FIG. 14 is a measurement result obtained by comparing and observing the rotation state of the rotor and the drive current waveform by a displacement meter due to the reflection of light, in which the rotor of the ultrasonic motor of the present invention is provided with 15 non-uniform portions due to grooves. is there.
【図１５】本発明の超音波モータの実施例の回転検出の
測定結果とステータの不均一部の数、圧電素子の電極の
分割数、および溝部を１、３、４本にしたときの結果を
まとめた一覧表である。FIG. 15 is a measurement result of rotation detection in the embodiment of the ultrasonic motor of the present invention, the number of non-uniform portions of the stator, the number of divisions of the electrodes of the piezoelectric element, and the results when the number of groove portions is 1, 3, and 4. It is a list that summarizes.
【図１６】本発明の超音波モータの溝部を有するロータ
の実施例を示す斜視図である．FIG. 16 is a perspective view showing an embodiment of a rotor having a groove portion of the ultrasonic motor of the present invention.
１ 圧電振動子 １ａ 振動子 １ｂ 圧電素子 １ｃ１、１ｃ２ 駆動電極 ２ フィルタ ３、４ 増幅器 ５ ９０゜移相器 ６ 発振回路 ７ 検出抵抗 ８ バッファ増幅検波回路 ９ フィルタ １０ 信号処理回路 １１ 摺動板 １２ ロータ体 １２ａ 摩擦材 １３ 加圧機構 １４ 支持板 １５ 中心軸 DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 1a Oscillator 1b Piezoelectric element 1c1, 1c2 Drive electrode 2 Filter 3, 4 Amplifier 5 90 ° phase shifter 6 Oscillation circuit 7 Detection resistor 8 Buffer amplification detection circuit 9 Filter 10 Signal processing circuit 11 Sliding plate 12 Rotor Body 12a Friction material 13 Pressure mechanism 14 Support plate 15 Center axis
Claims (6)
前記発振器よりの交流信号を増幅して出力する増幅器
と、前記増幅器よりの出力により励振される振動体と、
前記振動体により摩擦駆動されるロータより構成される
超音波モータにおいて、ロータの円周方向に不均一部を
設け、前記不均一部により強調される駆動電流の波高値
の包絡線を、連続またはパルス状の信号に変換する変換
回路を備え、前記ロータの回転状態を変換回路からの信
号により検出する回転検出手段を有することを特徴とす
る超音波モータ。1. An oscillator for generating a high-frequency AC signal,
An amplifier that amplifies and outputs an AC signal from the oscillator, and a vibrating body excited by the output from the amplifier,
In an ultrasonic motor composed of a rotor that is frictionally driven by the vibrating body, a non-uniform portion is provided in the circumferential direction of the rotor, and the envelope of the peak value of the drive current emphasized by the non-uniform portion is continuous or An ultrasonic motor comprising: a conversion circuit for converting the signal into a pulse signal, and a rotation detecting means for detecting a rotation state of the rotor by a signal from the conversion circuit.
均一部が溝部で構成され、溝部の幅が溝部以外の幅より
狭い請求項１記載の超音波モータ。2. The ultrasonic motor according to claim 1, wherein in the ultrasonic motor, the non-uniform portion of the rotor is formed by grooves, and the width of the grooves is narrower than the width other than the grooves.
均一部が凸部で構成され、凸部の幅が凸部以外の部分の
幅より狭い請求項１記載の超音波モータ。3. The ultrasonic motor according to claim 1, wherein in the ultrasonic motor, the non-uniform portion of the rotor is formed by convex portions, and the width of the convex portions is narrower than the width of portions other than the convex portions.
突起部の数が進行波の波の数の４＊Ｎ（Ｎ＝１、２、
３、．．．）倍である請求項１記載の超音波モータ。4. In the ultrasonic motor, the number of protrusions of the stator is 4 * N (N = 1, 2,
3 ,. ． ． The ultrasonic motor according to claim 1, wherein the ultrasonic motor is doubled.
均一部の数の２倍の駆動電流の波高値の包絡線の変化を
検出する検出回路を有する請求項４記載の超音波モー
タ。5. The ultrasonic motor according to claim 4, further comprising a detection circuit that detects a change in the envelope of the peak value of the drive current that is twice the number of non-uniform portions of the rotor.
均一部の数の３倍の駆動電流の波高値の包絡線の変化を
検出する検出回路を有する請求項４記載の超音波モー
タ。6. The ultrasonic motor according to claim 4, further comprising a detection circuit that detects a change in an envelope of a crest value of a drive current that is three times as large as the number of non-uniform portions of the rotor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5011873A JP3060081B2 (en) | 1993-01-27 | 1993-01-27 | Ultrasonic motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5011873A JP3060081B2 (en) | 1993-01-27 | 1993-01-27 | Ultrasonic motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06225550A true JPH06225550A (en) | 1994-08-12 |
| JP3060081B2 JP3060081B2 (en) | 2000-07-04 |
Family
ID=11789850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5011873A Expired - Fee Related JP3060081B2 (en) | 1993-01-27 | 1993-01-27 | Ultrasonic motor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3060081B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0723213A1 (en) * | 1994-12-29 | 1996-07-24 | Eta SA Fabriques d'Ebauches | Piezoelectric motor with means for delivering information about the position and/or the rotational speed of the rotor |
| JP2000060164A (en) * | 1998-06-02 | 2000-02-25 | Seiko Instruments Inc | Ultrasonic motor and electronic equipment with ultrasonic motor |
| JP2012124983A (en) * | 2010-12-06 | 2012-06-28 | Nikon Corp | Oscillatory wave motor, lens barrel and camera |
| JP2018067980A (en) * | 2016-10-17 | 2018-04-26 | キヤノン株式会社 | Drive circuit, vibration actuator and apparatus having the same |
| JPWO2022114181A1 (en) * | 2020-11-30 | 2022-06-02 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5679781B2 (en) | 2010-11-26 | 2015-03-04 | キヤノン株式会社 | Control device for vibration actuator |
| JP2014018027A (en) | 2012-07-11 | 2014-01-30 | Canon Inc | Vibration type actuator, imaging apparatus, and stage |
-
1993
- 1993-01-27 JP JP5011873A patent/JP3060081B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0723213A1 (en) * | 1994-12-29 | 1996-07-24 | Eta SA Fabriques d'Ebauches | Piezoelectric motor with means for delivering information about the position and/or the rotational speed of the rotor |
| CH686854GA3 (en) * | 1994-12-29 | 1996-07-31 | Ebauchesfabrik Eta Ag | Piezoelectric motor with device that provides information regarding the rotor position and / or speed. |
| US5719461A (en) * | 1994-12-29 | 1998-02-17 | Eta Fabriques D'ebauches | Piezoelectric motor having an arrangement which provides information relative to the rotor position and/or the rotor's number of revolutions |
| JP2000060164A (en) * | 1998-06-02 | 2000-02-25 | Seiko Instruments Inc | Ultrasonic motor and electronic equipment with ultrasonic motor |
| JP2012124983A (en) * | 2010-12-06 | 2012-06-28 | Nikon Corp | Oscillatory wave motor, lens barrel and camera |
| US8786163B2 (en) | 2010-12-06 | 2014-07-22 | Nikon Corporation | Vibrational wave motor, lens barrel and camera |
| JP2018067980A (en) * | 2016-10-17 | 2018-04-26 | キヤノン株式会社 | Drive circuit, vibration actuator and apparatus having the same |
| JPWO2022114181A1 (en) * | 2020-11-30 | 2022-06-02 | ||
| WO2022114181A1 (en) * | 2020-11-30 | 2022-06-02 | ミツミ電機株式会社 | Optical actuator, camera module, and camera-equipped device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3060081B2 (en) | 2000-07-04 |
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