JP2574284B2 - Ultrasonic motor - Google Patents
Ultrasonic motorInfo
- Publication number
- JP2574284B2 JP2574284B2 JP62072436A JP7243687A JP2574284B2 JP 2574284 B2 JP2574284 B2 JP 2574284B2 JP 62072436 A JP62072436 A JP 62072436A JP 7243687 A JP7243687 A JP 7243687A JP 2574284 B2 JP2574284 B2 JP 2574284B2
- Authority
- JP
- Japan
- Prior art keywords
- ultrasonic motor
- vibrator
- elastic body
- bending vibration
- ring
- 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 - Lifetime
Links
- 238000005452 bending Methods 0.000 claims description 21
- 230000002093 peripheral effect Effects 0.000 claims 2
- 238000000034 method Methods 0.000 claims 1
- 238000006073 displacement reaction Methods 0.000 description 7
- 239000002783 friction material Substances 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 4
- 238000005299 abrasion Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000012447 hatching Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
- H02N2/10—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors
- H02N2/16—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors using travelling waves, i.e. Rayleigh surface waves
- H02N2/163—Motors with ring stator
Landscapes
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は圧電体を用いて駆動力を発生する超音波モー
タに関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor that generates a driving force using a piezoelectric body.
従来の技術 近年圧電セラミック等の圧電体を用いた振動体に弾性
振動を励振し、これを駆動力とした超音波モータが注目
されている。2. Description of the Related Art In recent years, an ultrasonic motor that excites elastic vibrations in a vibrating body using a piezoelectric body such as a piezoelectric ceramic and uses this as a driving force has attracted attention.
以下、図面を参照しながら超音波モータの従来技術に
ついて説明を行う。Hereinafter, a conventional technique of an ultrasonic motor will be described with reference to the drawings.
第４図は従来の円環形超音波モータの斜視図であり、
円環形の弾性体１の円環面の一方に圧電体として円環形
の圧電セラミック２を貼合せて振動体３を構成してい
る。４は耐磨耗性材料の摩擦材、５は弾性体であり、互
いに貼合せられて移動体６を構成している。移動体６は
摩擦材４を介して振動体３と接触している。圧電体２に
電界を印加すると振動体３の周方向に曲げ振動の進行波
が励起され、移動体６を駆動する。尚、同図中の矢印は
移動体６の回転方向を示す。FIG. 4 is a perspective view of a conventional annular ultrasonic motor,
A vibrating body 3 is formed by bonding an annular piezoelectric ceramic 2 as a piezoelectric body to one of the annular surfaces of an annular elastic body 1. Reference numeral 4 denotes a friction material made of an abrasion-resistant material, and reference numeral 5 denotes an elastic body. The moving body 6 is in contact with the vibrating body 3 via the friction material 4. When an electric field is applied to the piezoelectric body 2, a traveling wave of bending vibration is excited in the circumferential direction of the vibrating body 3 to drive the moving body 6. Note that the arrow in the figure indicates the rotation direction of the moving body 6.
第５図は第４図の超音波モータに使用した圧電セラミ
ック２の電極構造の一例を示している。同図では円周方
向に９波の弾性波がのるようにしてある。同図におい
て、ＡおよびＢはそれぞれ２分の１波長相当の小領域か
ら成る電極群で、Ｃは４分の３波長、Ｄは４分の１波長
の長さの電極である。電極ＣおよびＤは電極群ＡとＢに
位置的に４分の１波長（＝90度）の位相差を作ってい
る。電極ＡとＢ内の隣り合う小電極部は互いに反対に厚
み方向に分極されている。圧電体２の弾性体１との接着
面は、第５図に示めされた面と反対の面であり、電極は
ベタ電極である。使用時には、電極群ＡおよびＢは第５
図に斜線で示されたように、それぞれ短絡して用いられ
る。FIG. 5 shows an example of the electrode structure of the piezoelectric ceramic 2 used in the ultrasonic motor of FIG. In the figure, nine elastic waves are applied in the circumferential direction. In the figure, A and B are electrode groups each composed of a small area corresponding to a half wavelength, C is an electrode having a length of 3/4 wavelength, and D is an electrode having a length of a quarter wavelength. The electrodes C and D form a phase difference of a quarter wavelength (= 90 degrees) between the electrode groups A and B in position. The adjacent small electrode portions in the electrodes A and B are polarized in the thickness direction opposite to each other. The bonding surface of the piezoelectric body 2 with the elastic body 1 is a surface opposite to the surface shown in FIG. 5, and the electrodes are solid electrodes. In use, the electrode groups A and B are
As shown by hatching in the figure, each is used after being short-circuited.
以上のように構成された超音波モータの圧電体２の電
極ＡおよびＢに V1＝V0×sin（ωｔ） −−−（１） V2＝V0×cos（ωｔ） −−−（２） ただし、 V0:電圧の瞬時値 ω：角周波数 t:時間 で表される電圧V1およびV2をそれぞれ印加すれば、振動
体３には ξ＝ξ０×（cos（ωｔ）×cos（kx） ＋sin（ωｔ）×sin（kx）） ＝ξ０×cos（ωｔ−kx） −−−（３） ただし ξ：曲げ振動の振幅値 ξ0:曲げ振動の瞬時値 k:波数（２π／λ） λ：波長 x:位置 で表せる、円周方向に進行する曲げ振動の進行波が励起
される。V 1 = V 0 × sin (ωt) −1 (1) V 2 = V 0 × cos (ωt) −−− (1) 2) However, if voltages V 1 and V 2 represented by V 0 : instantaneous value of voltage ω: angular frequency t: time are respectively applied, 振動 = ξ 0 × (cos (ωt) × cos (kx) + sin (ωt ) × sin (kx)) = ξ 0 × cos (ωt-kx) --- (3) However xi]: bending vibration amplitude xi] 0: bending instantaneous value k of the vibration wave number ( 2π / λ) λ: wavelength x: position Exciting a traveling wave of bending vibration that travels in the circumferential direction and is expressed by:
第６図は振動体３の表面のＡ点が進行波の励起によっ
て、長軸2w、短軸2uの楕円運動をし、振動体３上に加圧
して設置された移動体６が、楕円の頂点近傍で接触する
ことにより、摩擦力により波の進行方向とは逆方向にｖ
＝ω×ｕの速度で運動する様子を示している。FIG. 6 shows that point A on the surface of the vibrating body 3 performs an elliptic motion of a long axis 2w and a short axis 2u by excitation of a traveling wave, and a moving body 6 placed under pressure on the vibrating body 3 has an elliptical shape. By contact near the vertex, frictional force causes v
= Ω x u.
発明が解決しようとする問題点 第７図に円環形超音波モータの振動体の径方向の変位
分布を示す。超音波モータの出力を大きくするために
は、振動体の変位または質量を大きくして運動エネルギ
ーを大きくすればよい。振動体の外径が決まれば、内径
をできるだけ小さくするか、厚さを厚くするか、または
変位を大きくしなければならない。しかし、内径を小さ
くしても、内径が小さくなるに従って、第７図に示すよ
うに急に振幅値は小さくなり、振動体の穴を小さくして
も運動エネルギーはあまり大きくならない。そして、厚
さを厚くすれば振動体の曲げ剛性が大きくなり変位を大
きくすることはできない。また、変位の増大は破壊限界
により上限が決まっている。従って、従来の円環の曲げ
振動を使用した超音波モータは出力を大きくできないと
いう問題点がある。7. Problems to be Solved by the Invention FIG. 7 shows a radial displacement distribution of the vibrating body of the annular ultrasonic motor. In order to increase the output of the ultrasonic motor, the kinetic energy may be increased by increasing the displacement or mass of the vibrator. Once the outer diameter of the vibrating body is determined, the inner diameter must be reduced as much as possible, the thickness must be increased, or the displacement must be increased. However, even if the inside diameter is reduced, as the inside diameter becomes small, the amplitude value suddenly decreases as shown in FIG. 7, and even if the hole of the vibrating body is reduced, the kinetic energy does not increase so much. If the thickness is increased, the bending rigidity of the vibrating body increases, and the displacement cannot be increased. The upper limit of the displacement is determined by the breaking limit. Accordingly, there is a problem that the output of the conventional ultrasonic motor using the bending vibration of the ring cannot be increased.
本発明はかかる点に鑑みてなされたもので、同体積で
出力を大きくでき、しかも効率の良い超音波モータを提
供することを目的としている。The present invention has been made in view of the above, and an object of the present invention is to provide an efficient ultrasonic motor capable of increasing the output with the same volume.
問題点を解決するための手段 円環形振動体を構成する弾性体に、径方向に複数個の
幅が一定なスリットを入れる。Means for Solving the Problems A plurality of slits having a constant width in the radial direction are formed in the elastic body constituting the toroidal vibrator.
作 用 円環形振動体を構成する弾性体に、径方向に複数のス
リットを入れることにより、振動体の厚さを厚くしても
等価的に曲げ剛性が小さい構造をとり、スリットの幅を
一定にすることにより、曲げ振動を効率良く励振するこ
とができ、変位を大きくとり、しかも振動体の機械的損
失を小さくして、その結果出力が大きく、効率の良い超
音波モータを実現できる。Effect By making multiple slits in the radial direction in the elastic body that constitutes the toroidal vibrating body, a structure with equivalently low bending rigidity is obtained even when the vibrating body is thickened, and the width of the slit is kept constant. Thus, the bending vibration can be efficiently excited, the displacement can be increased, and the mechanical loss of the vibrator can be reduced. As a result, an efficient ultrasonic motor having a large output can be realized.
実施例 以下、図面に従って本発明の一実施例について詳細な
説明を行う。Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
第１図は本発明の超音波モータの構成を示す切り欠き
斜視図である。円環形の弾性体７の主面の一方に、圧電
体として円環形の圧電セラミック８を貼合せて振動体９
を構成している。また、弾性体７の他の主面には、幅が
一定なスリット10が構成されている。このスリット10に
より振動体９の曲げ振動の進行方向の曲げ剛性は見掛け
上小さくできる。11は耐磨耗性材料の摩擦材、12は弾性
体であり、互いに貼合せられて移動体13を構成してい
る。移動体13は、摩擦材11を介して振動体９に加圧接触
している。圧電体８に電界を印加すると振動体９の周方
向に曲げ振動の進行波が励起され、移動体13を摩擦力に
より駆動し、移動体13は回転運動を始める。FIG. 1 is a cutaway perspective view showing the configuration of an ultrasonic motor according to the present invention. A ring-shaped piezoelectric ceramic 8 is bonded to one of the main surfaces of the ring-shaped elastic body 7 as a piezoelectric body to form a vibrating body 9.
Is composed. On the other main surface of the elastic body 7, a slit 10 having a constant width is formed. By the slit 10, the bending rigidity of the vibrating body 9 in the traveling direction of the bending vibration can be apparently reduced. Numeral 11 denotes a friction material made of an abrasion-resistant material, and 12 denotes an elastic body. The moving body 13 is in pressure contact with the vibrating body 9 via the friction material 11. When an electric field is applied to the piezoelectric body 8, a traveling wave of bending vibration is excited in the circumferential direction of the vibrating body 9, and the moving body 13 is driven by a frictional force, and the moving body 13 starts rotating.
第２図は、第１図の超音波モータの振動体９を構成す
る弾性体７の平面図と側面図である。同図より、スリッ
ト10の入っている部分と入っていない部分とでは厚さが
大きく異なり、そのため曲げ剛性が双方で大きく異な
り、曲げ振動の大部分はスリット10の部分で変位してい
る。弾性体７の径方向に放射状に入れられたスリット10
は、その円周方向の幅W0を一定にしている。これによ
り、スリット部での駆動は矩形の貼合素子と同様の動作
をすることになり、内外周のスリットの幅が異なる等価
的に扇形の貼合素子とみなせる場合よりも、機械損失の
小さい駆動ができる。また、同図中のλは１波長を示
し、スリットが１波長相当長に８個入っていることを示
す。FIG. 2 is a plan view and a side view of the elastic body 7 constituting the vibrating body 9 of the ultrasonic motor of FIG. As shown in the figure, the thickness of the portion where the slit 10 is included is greatly different from the thickness of the portion where the slit 10 is not included. Slit 10 radially inserted in the elastic body 7 in the radial direction
Has a constant width W 0 in the circumferential direction. Thereby, the driving in the slit portion performs the same operation as the rectangular bonding element, and the mechanical loss is smaller than that in a case where the widths of the slits on the inner and outer circumferences can be regarded as equivalently fan-shaped bonding elements. Can be driven. In the figure, λ indicates one wavelength, which indicates that eight slits are included in a length corresponding to one wavelength.
第３図は振動体の曲げ振動とスリットとの関係を示す
説明図である。同図で、Ａ、Ｂは互いに位置的に位相が
４分の１波長相当分だけ異なる電極群で、それぞれ２分
の１波長相当分の小電極より成る。上記の隣り合う小電
極部は厚さ方向に反対方向に分極されている。電極群Ａ
にsinの交流電圧を印加したとき励振される曲げ振動の
定在波をＡで表し、電極群Ｂにcosの交流電圧を印加し
たとき励振される曲げ振動の定在波をＢで表す。電極群
Ａ、Ｂにより定在波が効率良く励振されるように、２つ
の定在波Ａ、Ｂのいずれの定在波の振動の腹近傍の位置
に必ずスリットがあるように、振動体にスリット10を入
れるという条件のもとでは、スリットは曲げ振動の１波
長当たりに４の整数倍個入れねばならない。逆に、この
条件を満たせば、定在波Ａ、Ｂの何れから見ても、定在
波の腹と節の位置とスリットとの位置関係は同じにな
る。従って、２つの定在波は同じ条件で励振され、理想
的な曲げ振動の進行波が得られる。FIG. 3 is an explanatory diagram showing a relationship between bending vibration of a vibrating body and a slit. In the figure, A and B are electrode groups whose phases differ from each other in position by an amount corresponding to a quarter wavelength, and are each composed of small electrodes corresponding to a half wavelength. The adjacent small electrode portions are polarized in the direction opposite to the thickness direction. Electrode group A
A represents a standing wave of bending vibration excited when a sin AC voltage is applied to the electrode group B, and B represents a standing wave of bending vibration excited when a cos AC voltage is applied to the electrode group B. In order to excite the standing wave efficiently by the electrode groups A and B, the vibrating body is provided so that there is always a slit at a position near the antinode of the vibration of any of the two standing waves A and B. Under the condition that the slit 10 is provided, the number of slits must be an integral multiple of 4 per one wavelength of bending vibration. Conversely, if this condition is satisfied, the positional relationship between the antinode of the standing wave, the position of the node, and the slit becomes the same from both of the standing waves A and B. Accordingly, the two standing waves are excited under the same conditions, and an ideal traveling wave of bending vibration is obtained.
本発明によれば、効率の良い、しかも出力の大きな超
音波モータを提供できる。According to the present invention, it is possible to provide an efficient ultrasonic motor having a large output.
発明の効果 本発明によれば、円環形振動体を構成する弾性体に、
その幅が一定なスリットを形成して、曲げ振動を効率良
く励振することにより、効率の良い、しかも出力の大き
な超音波モータを提供できる。Effect of the Invention According to the present invention, the elastic body constituting the toroidal vibrator,
By forming a slit having a constant width to efficiently excite the bending vibration, it is possible to provide an efficient ultrasonic motor having a large output.
第１図は本発明の円環形超音波モータの切り欠き斜視
図、第２図は第１図の超音波モータで使用する振動体を
構成する弾性体の平面図と側面図、第３図は振動体の曲
げ振動を構成する２つの定在波とスリットとの位置関係
を説明するモデル図、第４図は従来の円環形超音波モー
タの切り欠き斜視図、第５図は第４図の超音波モータに
用いた圧電体の形状と電極構造とを示す平面図、第６図
は超音波モータの動作原理の説明図、第７図は振動体の
曲げ振動の振動状態と径方向の変位分布図である。 ７……弾性体、８……圧電体、９……振動体、10……ス
リット、11……摩擦材、12……弾性体、13……移動体。FIG. 1 is a cutaway perspective view of an annular ultrasonic motor of the present invention, FIG. 2 is a plan view and a side view of an elastic body constituting a vibrator used in the ultrasonic motor of FIG. 1, and FIG. FIG. 4 is a model diagram for explaining a positional relationship between two standing waves and a slit constituting bending vibration of a vibrating body, FIG. 4 is a cutaway perspective view of a conventional annular ultrasonic motor, and FIG. FIG. 6 is a plan view showing the shape and electrode structure of the piezoelectric body used in the ultrasonic motor, FIG. 6 is an explanatory view of the operation principle of the ultrasonic motor, and FIG. 7 is the vibration state and radial displacement of bending vibration of the vibrating body. It is a distribution map. 7 ... elastic body, 8 ... piezoelectric body, 9 ... vibrating body, 10 ... slit, 11 ... friction material, 12 ... elastic body, 13 ... moving body.
Claims (2)
と弾性体とから構成される振動体に弾性進行波を励振す
ることにより、前記振動体上に接触して設置された移動
体を移動させる超音波モータにおいて、 円環形弾性体の前記移動体との接触面の反対面に円環形
圧電体を固着して円環形振動体を構成し、 前記振動体の円周方向に進行する曲げ振動の進行波を励
振し、 前記弾性体の前記接触面側に、円周方向の幅が前記弾性
体の内周部と外周部で一定なスリットを、放射状に複数
個設けることを特徴とする超音波モータ。A moving member disposed in contact with the vibrating body by driving the piezoelectric body with an AC voltage to excite a vibrating body composed of the piezoelectric body and the elastic body with an elastic traveling wave; In an ultrasonic motor for moving a body, a ring-shaped piezoelectric body is fixed to a surface of the ring-shaped elastic body opposite to a contact surface with the moving body to form a ring-shaped vibrator, and the ring-shaped vibrator moves in a circumferential direction of the vibrator. Exciting a traveling wave of bending vibration, wherein a plurality of slits are provided radially on the contact surface side of the elastic body, the slits having a constant width in the circumferential direction at an inner peripheral portion and an outer peripheral portion of the elastic body. Ultrasonic motor.
する曲げ振動の１波長相当長に、４の整数倍個のスリッ
トを設けることを特徴とする特許請求の範囲第１項記載
の超音波モータ。2. The method according to claim 1, wherein a number of slits equal to an integral multiple of 4 is provided for a length corresponding to one wavelength of the circumferentially excited bending vibration excited in the toroidal vibrator. Ultrasonic motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62072436A JP2574284B2 (en) | 1987-03-26 | 1987-03-26 | Ultrasonic motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62072436A JP2574284B2 (en) | 1987-03-26 | 1987-03-26 | Ultrasonic motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63240382A JPS63240382A (en) | 1988-10-06 |
| JP2574284B2 true JP2574284B2 (en) | 1997-01-22 |
Family
ID=13489250
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62072436A Expired - Lifetime JP2574284B2 (en) | 1987-03-26 | 1987-03-26 | Ultrasonic motor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2574284B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06101945B2 (en) * | 1987-06-15 | 1994-12-12 | セイコー電子工業株式会社 | Ultrasonic motor |
| JP2698414B2 (en) * | 1989-02-17 | 1998-01-19 | キヤノン株式会社 | Vibration wave device |
| JP2698412B2 (en) * | 1989-02-14 | 1998-01-19 | キヤノン株式会社 | Vibration wave device |
| US11469689B2 (en) | 2018-06-08 | 2022-10-11 | Canon Kabushiki Kaisha | Vibration wave motor, drive control system, and optical apparatus |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59201685A (en) * | 1983-04-30 | 1984-11-15 | Canon Inc | Vibration wave motor |
| JPS61116978A (en) * | 1984-11-08 | 1986-06-04 | Matsushita Electric Ind Co Ltd | Supersonic wave drive motor |
| JPS61191278A (en) * | 1985-02-20 | 1986-08-25 | Matsushita Electric Ind Co Ltd | Ultrasonic wave motor |
-
1987
- 1987-03-26 JP JP62072436A patent/JP2574284B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63240382A (en) | 1988-10-06 |
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