JP4136037B2

JP4136037B2 - Vibration type actuator and method for assembling vibration type actuator

Info

Publication number: JP4136037B2
Application number: JP27435997A
Authority: JP
Inventors: 裕之関
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1997-10-07
Filing date: 1997-10-07
Publication date: 2008-08-20
Anticipated expiration: 2017-10-07
Also published as: JPH11122955A

Description

【０００１】
【発明の属する技術分野】
本発明は振動型アクチュエータに係り、特に、ランジュバン型振動子を用いた振動型アクチュエータに関するものである。
【０００２】
【従来の技術】
電界や磁界が作用したことに応じて、機械的歪を生じる電気−機械エネルギー変換素子としての歪発生素子を弾性体に取り付けて振動体となし、該歪発生素子により該弾性体を振動せしめ、該弾性体の振動を連続的もしくは断続的な機械運動に変換して出力する振動型アクチュエータは、現在では種々の分野で使用されており、特に、歪発生素子として圧電素子および電歪素子を利用する圧電／電歪アクチュエータが最も広く使用されている。
【０００３】
また、該圧電素子を利用する振動型アクチュエータのうちで振動波モータと称されるアクチュエータは連続回転式の回転駆動源を構成できるため、従来の回転式電磁駆動モータに代わる駆動源としてカメラ等の光学機器に搭載されている。
【０００４】
【発明が解決しようとする課題】
振動型アクチュエータは種々のタイプのものが提案されており、現在製品化されている振動波モータは大別すると、
１）平板またはリング状の弾性体に進行性振動波を励振し、これにやはり円板状またはリング状のロータを加圧接触させる扁平なタイプと、
２）ランジュバン型振動体にロータを加圧接触させる棒状のタイプ（いわゆるペンシルタイプ）がある。
【０００５】
これらの振動型アクチュエータとして、図９は従来のリング状の振動波モータで、ケース２４に対して支持された圧電素子２５と共にリング状の振動体を構成する弾性体２０に対して、出力軸２２と一体に回転するロータ２１が皿ばね２３により加圧接触している。
【０００６】
ここに代表される振動波モータの大きな課題の１つに、コストが高いということがある。これは進行波タイプの振動波モータでは、
１）２つの異なる振動モードの共振周波数を合わせる（なるべく近づける）ために、円環形状の弾性体の形状精度を厳しく管理している（数μｍから数十μｍ）ため、どうしても機械加工に頼らざるを得ず、鍛造、粉末焼結、プレスなどの量産加工がなかなか使えないこと、
２）圧電素子のコストが高い（特に大径のリングタイプの振動体では材料を捨てる部分が多いこと、電極付け、分極などの後工程が多いこと）、
３）圧電素子の接着工程がある（接着の良否によりモータ性能が大きく左右されるので、接着面の洗浄、面精度、接着条件などには細心の注意を払っている）
などが挙げられる。
【０００７】
これに代わって、図８に示すように、コスト的に有利な棒状の振動波モータが提案されている。
【０００８】
この振動波モータは、外径と同軸の穴部を中央部に有する第１の弾性体１と第２の弾性体２との間に、複数のＰＺＴ３と給電用電極板を挟み、それらの穴を貫通させたシャフト５の雄ネジ部を弾性体１の内ネジ部１ｅに螺合させ、シャフト５の頭部との間でＰＺＴ３等を介装した弾性体１，２を締め付けることにより、ランジュバン型振動体を形成している。
【０００９】
一方、シャフト５の周囲には、ギア１１と係合すると共にバネケース９とスラスト方向で当接するロータ８、加圧バネ１４が内装されるバネケース９、ボールベアリング１０に回転可能に軸支されたギア１１、ボールベアリング１０が装着されたモータ取り付け用フランジ１２が配置され、モータ取り付け用フランジ１２はナット部材１３により固定されている。ロータ８は加圧バネ１４のバネ力がバネケース９を介して伝達され、弾性体１の駆動面に加圧接触する。また、回転力はギア１１に伝達され外部に出力される。
【００１０】
ＰＺＴ３に駆動信号である交番信号、例えば周波電圧が印加されると、第１の弾性体１の駆動面に曲げ振動の合成で駆動波が形成され、この駆動波によりロータ８が摩擦駆動される。
【００１１】
この図８に示す棒状の振動波モータは小径化が可能（圧電素子を積層化できるので、モータを小径化しても入力電力を投入できる）であり、ランジュバンタイプなので圧電素子の接着レスなど構造的にローコスト化に向いており、実際、図９のタイプの振動波モータに比べかなりのコストダウンが実現できた。
【００１２】
しかし、まだ同程度の出力で比較すると小型の電磁式のモータに比べコストは数倍高く、振動波モータならではの特徴（例えば静かさ、ダイレクト駆動が可能、保持力があるなど）が十分生かせる限られた分野でしか採用されないのが実情である。
【００１３】
そこで、さらにローコスト化を実現する為に、図７に示す構造のモータを本発明者らが提案している。図７に示す振動波モータの構造において、図８の構造と異なる点は、振動子とシャフトの構造及び形状である。すなわち、図７の振動波モータにおいては、第１の弾性体１及び第２の弾性体２には、これらの部材の中心部を貫通する穴が設けられており、シャフト５に設けられたフランジ部５ａとナット６とにより、第１，第２の弾性体１，２及び圧電素子３とを所定の加圧力で挟持する構造になっている。
【００１４】
こうすることで、図８の第１の弾性体に設けられていたネジ部を廃止できること、シャフトの形状がヘッダ加工等量産性のある加工をしやすい形状にできること（シャフトの最大径と最小径の差が小さくなった為）等により図８の構造よりもかなりローコスト化が実現できた。
【００１５】
これらの部材１〜４は、組立て性を考慮し、シャフトに対して容易に係合できる様にガタ嵌合とし、外径を治具等でそろえる様にすることで、これら１〜４の部材の同軸度を出している。
【００１６】
しかしながら、第１の弾性体の穴と、シャフト５の軸部５ｂとがガタを有していると、振動子が振動した時にシャフトと第１の弾性体との間で、わずかに相対的なずれが生じる為、シャフトのフランジ５ａと第１の弾性体の接触面１ｂとの摩擦損失が生じ、モータ性能が低下するという問題があった。
【００１７】
本出願に係る発明は、ローコスト化した棒状タイプの振動波モータ等の振動型アクチュエータの特性をさらに改善することを目的としている。
【００１８】
【課題を解決するための手段】
本願発明である振動型アクチュエータは、中心部にそれぞれ締結用のシャフト部材が貫通する孔部を有する弾性体と電気−機械エネルギー変換素子を配置し、前記シャフト部材に設けたフランジ部と、前記シャフト部材に螺合され、前記フランジ部と対向する位置に設けられた締結部材により、前記弾性体と前記電気−機械エネルギー変換素子をその両側から挟持して一体化した振動体を有する振動型アクチュエータにおいて、前記締結部材の締結動作による加圧力を用いて、前記弾性体のうち前記フランジ部と当接するシャフト受け面の一部に塑性変形、または、塑性流動を生じさせて前記弾性体の孔部と前記シャフト部材の間に入り込ませることにより、前記弾性体及び前記シャフト部材を結合している。
【００２１】
ここで、弾性体のシャフト受け面に、フランジ部からの押圧力を受けて塑性変形又は塑性流動する突起部を設けることができる。この場合には、前記締結動作により、前記突起部を押しつぶすことにより、前記シャフト受け面の一部に塑性変形、または、塑性流動を生じさせることができる。
【００２２】
また、前記シャフト部材における前記フランジ部と前記孔部を貫通する貫通部との境界部分を、第１の曲率半径を有する曲面とし、前記弾性体の前記シャフト受け面の端部と前記孔部の面との稜部を、前記シャフト部材の前記曲面よりも小さな面取り部、または前記第１の曲率半径よりも小さい第２の曲率半径をもつ角部とすることができる。この場合には、前記締結動作により、前記稜部を押しつぶすことにより、前記シャフト受け面の一部に塑性変形、または、塑性流動を生じさせることができる。
【００２４】
本願発明である振動型アクチュエータの組立て方法は、中心部にそれぞれ締結用のシャフト部材が貫通する孔部を有する弾性体と電気−機械エネルギー変換素子を配置し、前記シャフト部材に設けたフランジ部と、前記シャフト部材に螺合され、前記フランジ部と対向する位置に設けられた締結部材により、前記弾性体と前記電気−機械エネルギー変換素子をその両側から挟持して一体化した振動体を有する振動型アクチュエータの組立て方法において、前記弾性体と電気−機械エネルギー変換素子のそれぞれの孔部に前記シャフト部材を貫通させ、前記シャフト部材に対する前記締結部材の締め付け力を用いて、前記弾性体のうち前記フランジ部と当接するシャフト受け面の一部に塑性変形、または、塑性流動を生じさせて前記弾性体の孔部と前記シャフト部材の間に入り込ませることにより、前記弾性体及び前記シャフト部材を結合させている。
【００２５】
【発明の実施の形態】
（第１の実施の形態）
図１、図２は本発明の第１の実施の形態を示す。
【００２６】
図１は本発明の第１の実施の形態を示す振動型アクチュエータとしての棒状振動波モータの断面図を示し、図２は、第１の弾性体１のシャフトとの当接面１ｂに、シャフトを締め付けた時に塑性変形する様に設けた突起部分の拡大図を示す。
【００２７】
それぞれの中央部に外径と同軸のとれた穴を有する第１の弾性体１と第２の弾性体２との間に積層ＰＺＴ３および給電用フレキ４を挟み、それらの穴を貫通させたシャフト５のフランジ部５ａとナット６とで前記１〜４の部材を締め付けることによりランジュバン型振動体を形成している。また、第１の弾性体１の図中上部には摩擦リング７（ＳＵＳ４２０Ｊ２焼き入れ品）が接着剤により接合されている。
【００２８】
一方、アルミ製のロータ８にはアルマイト処理が施され、コイルバネ１４をガイドするシリンダー部８ａと、その下側にバネを受けるフランジ部８ｂが一体的に設けられている。このコイルバネ１４は、該ロータ８のフランジ部８ｂと、ギア１１とで挟み込んで圧縮され、ギア１１に対しロータ８を振動体の摩擦リング７に押しつけている。
【００２９】
ギア１１は、シャフト５に設けられた位置決め用段差５ｅにより位置決めされたモータ取付用フランジ１２と、これを固定するためのナット１３により、スラスト方向には位置決めされ、また、前記モータ取付用フランジ１２の円筒部外径と、ギア１１の内径とがタガなく係合し、該ギア１１は回転自在に支持されている。
【００３０】
上記構成の振動波モータの駆動は、不図示の電源から位相のずれた２相の交番信号を積層ＰＺＴ３に印加すると、シャフト５の長手方向に対する２方向の曲げ振動が前記振動体に励振され、該振動体は縄跳び運動をする。このとき摩擦リングの摺動面には楕円振動が起こり、これによりロータ８、ギア１１は一体となって回転する。なお、ロータ８には半径方向に２本の不図示の溝が設けられており、この溝とギア１１に設けられた不図示の２本の突起がガタなく嵌合しているので、ロータ８の回転力がロスなくギア１１に伝達されるよう構成されている。
【００３１】
図２は図１のＡ部における第１の弾性体１のシャフトとの係合部の形状の拡大断面図を示す。図２の（ａ）はシャフト５を締め付ける前の形状を示す。
【００３２】
シャフト５のフランジ部５ａに対する弾性体１の当接面１ｂには、シャフトのスラスト方向に突出した突起部１ｃが内周面側に設けられている。
【００３３】
シャフト５の軸部５ｂの径は、第１の弾性体１の中心穴１ａの径より０〜０．０４ｍｍ（単位は以降ｍｍで表す）程度マイナス公差に設定されており、組立て時には、容易に前記シャフトを第１の弾性体１に挿入することができる。なお本実施の形態においては、シャフト５の軸部５ｂの外径φＤ _２を
【００３４】
【外１】

【００３５】
第１の弾性体１の穴部１ａの内径φＤ _１を
【００３６】
【外２】

【００３７】
に設定した。
【００３８】
また、シャフト５のフランジ部５ａと軸部５ｂとの境界部５ｃは、約０．２の曲率半径Ｒがついている。
【００３９】
振動体の組立て時に、第１の弾性体１、積層ＰＺＴ３、フレキ４、第２の弾性体２の中心貫穴にシャフト５を挿入し、ナット６により前記部材１〜４を締め付けると、シャフト５は弾性体１に対し図２（ａ）のＢ方向に押し付けられ、シャフトフランジ５ａが第１の弾性体１の当接面１ｂに設けられた突起部１ｃを押しつぶし、その余肉が塑性流動し、該塑性流動部分１ｃ’が図２（ｂ）の斜線で示す様に、該シャフトと該第１の弾性体とのすき間を埋めるため、シャフト５のフランジ部５ａの近傍における軸部５ｂと第１の弾性体１の当接面１ｂ付近がガタなく一体的に結合される。このため、該振動体に曲げ振動を励振した場合でも、該シャフト５のフランジ部５ａと軸部５ｂと該弾性体１の当接面１ｂ、突起部１ｃとは相対的にすべり摩擦を起こすことなく一体的に振動するため、振動体の振動損失（内部損失）を最小限に抑えることができ、良好な振動特性及びモータ性能を得ることができる。
【００４０】
なお、図２の（ａ）に示す突起部１ｃは内周側の斜面を緩斜面、外周側の斜面を急斜面としているが、図２（ｃ）に示すように、突起部１ｃの形状を、内周面を垂直面とし、外周面を斜面とする形状であってもよい。
【００４１】
（第２の実施の形態）
図３（ａ）〜（ｃ）は本発明における第２の実施の形態を示す。
【００４２】
図３（ａ）は、第１の弾性体１の貫穴の内周面１ａと当接面１ｂとの境界部に面取りを施した面取り部１ｄを設けたもので、この面取り量は、前記シャフト５のＲ部５ｃのＲ（半径）よりも小さくしている。これは、面取り部１ｄの面取り量がＲ部５ｃの半径Ｒより大きい場合、図３（ｃ）の様に、シャフト５のフランジ部５ａが当接面１ｂに突き当っても、面取り部１ｄがシャフト５のフランジ部５ａ，軸部５ｂ，Ｒ部５ｃに当たらないため、弾性体１の材料の一部を塑性流動させて、軸部５ｂと弾性体１の貫穴の内周面１ａとのガタを埋めることができない為である。
【００４３】
図３（ａ）の様に、シャフト５の非締め付け状態において、面取り部１ｄがシャフト５のＲ部５ｃに当接し、当接面１ｂ，面取り部１ｄはシャフト５とは非接触の面取り部１ｄを設定し、シャフト５を挿入して、締め付け力を与えると、シャフト５は弾性体１に対し矢印Ｂ方向に移動し、シャフト５のフランジ部５ａと弾性体１の当接面１ｂは密着する為に、面取り部１ｄは、シャフト５のＲ部５ｃにより押しつぶされ、斜線部１ｅの余肉は斜線部１ｆに流動して、シャフト５と弾性体１とは、弾性体１の貫穴内に入り込んだ部分１ｆで一体的に結合されることとなる。
【００４４】
（第３の実施の形態）
図４は第３の実施の形態を示す。
【００４５】
本実施の形態では、第２の実施の形態において設けた面取り部１ｄをさらに小さくし、ほぼ面取り量を０にした例（面取り部１ｇ）である。この場合、シャフト５のフランジ部５ａおよびＲ部５ｃにより押しつぶされる量が多くなるので、シャフト５と弾性体１との設定公差によるガタが多い場合に有効である。
【００４６】
（第４の実施の形態）
図５は本発明の第４の実施の形態を示す。
【００４７】
本実施の形態では、第１の弾性体１の角部１ｇに塑性変形（又は塑性流動）しやすい別部材１５を設けている。前記した第１〜第３の実施の形態では、振動特性が良く、また、シャフト締め付け力により一部が塑性流動しやすい材料として真ちゅうやアルミ材を使用したが、本実施の形態では、弾性体１の材料として、ステンレスや鉄など硬い材料を使用し、塑性変形させたい部分に適当な別部材（別材質）１５を設け、前記した第１〜第３の実施の形態と同じ効果をもたせたものである。
【００４８】
この別部材１５の材質としては、真ちゅう、アルミはもちろん、亜鉛、鉛などの金属又はある程度ヤング率が高く、振動減衰の少ない高分子化合物などでもよい。
【００４９】
（参考の実施の形態）
図６は本発明における第５の実施の形態を示す。
【００５０】
上記した各実施の形態では、締結動作に伴う加圧力により突起部を塑性変形させるという間接的な係合方式を採用しているが、本実施の形態では、第１の弾性体１とシャフト５とを圧入又は焼ばめ、又は冷しばめ等のように、締結動作に伴う加圧力を直接的に受けて前記シャフト部材とガタなく一体的に係合し、これらの２部品を一体的に構成するようにしている。
【００５１】
尚、図では示さないが、シャフト５の軸部５ｂにローレットを施し圧入をしやすい構造にしてもよい。
【００５２】
【発明の効果】
本発明によれば、振動型アクチュエータにおける振動体のローコスト化を図った構造においても、振動励振時にシャフト部材と弾性体との間に生ずる摩擦損失（振動体の内部損失）を激的に削減することが可能となり、効率の良い振動型アクチュエータを提供できる。
【図面の簡単な説明】
【図１】本発明を適用した第１〜第５の実施の形態棒状振動波モータの断面図。
【図２】（ａ）、（ｂ）は図１の振動波モータにおける振動体の組立状態を示すＡ部の部分拡大断面図、（ｃ）は突起部の変形例を示す部分断面図。
【図３】（ａ）〜（ｃ）は本発明を適用した棒状振動波モータの第２の実施の形態における図１のＡ部の部分拡大図。
【図４】本発明における第３の実施の形態を示す図１のＡ部の部分拡大図。
【図５】本発明における第４の実施の形態を示す図１のＡ部の部分拡大図。
【図６】本発明における参考の実施の形態を示すＡ部拡大図。
【図７】従来の棒状ランジュバン型振動波モータの断面図。
【図８】従来の他の棒状ランジュバン型振動波モータの断面図。
【図９】従来の円環型振動波モータの断面図。
【符号の説明】
１…第１の弾性体
２…第２の弾性体
３…積層ＰＺＴ
４…フレキ（フレキシブルプリント配線板）
５…シャフト
６…ナット
７…摩擦リング
８…ロータ
９…バネケース
１０…ボールベアリング
１１…ギア
１２…振動波モータフランジ
１３…ナット
１４…バネ
１５…塑性変形させる為の部材
２０…振動体
２１…ロータ
２２…シャフト
２３…加圧バネ
２４…振動波モータカバー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration type actuator, and more particularly to a vibration type actuator using a Langevin type vibrator.
[0002]
[Prior art]
A strain generating element as an electro-mechanical energy conversion element that generates mechanical strain in response to the action of an electric field or magnetic field is attached to an elastic body to form a vibrating body, and the elastic body is vibrated by the strain generating element, The vibration type actuator that converts the vibration of the elastic body into a continuous or intermittent mechanical motion and outputs it is currently used in various fields. In particular, a piezoelectric element and an electrostrictive element are used as a strain generating element. Piezoelectric / electrostrictive actuators are most widely used.
[0003]
In addition, among the vibration type actuators using the piezoelectric element, an actuator called a vibration wave motor can constitute a continuous rotation type rotational drive source, so that a camera or the like can be used as a drive source in place of a conventional rotary electromagnetic drive motor. Installed in optical equipment.
[0004]
[Problems to be solved by the invention]
Various types of vibration-type actuators have been proposed, and the vibration wave motors currently on the market are roughly classified.
1) A flat type in which a progressive vibration wave is excited in a flat plate or ring-shaped elastic body, and a disk-shaped or ring-shaped rotor is also brought into pressure contact therewith,
2) There is a rod type (so-called pencil type) in which the rotor is brought into pressure contact with the Langevin type vibrating body.
[0005]
As these vibration type actuators, FIG. 9 shows a conventional ring-shaped vibration wave motor, which has an output shaft 22 with respect to an elastic body 20 constituting a ring-shaped vibration body together with a piezoelectric element 25 supported by a case 24. The rotor 21 rotating integrally with the disc spring 23 is in pressure contact with the disc spring 23.
[0006]
One of the major problems of the vibration wave motor represented here is that the cost is high. This is a traveling wave type vibration wave motor.
1) In order to match the resonance frequencies of two different vibration modes (as close as possible), the shape accuracy of the annular elastic body is strictly controlled (several μm to several tens of μm), so it is unavoidable to rely on machining. That mass production processes such as forging, powder sintering, and pressing are difficult to use,
2) The cost of the piezoelectric element is high (especially in the case of a large-diameter ring-type vibrator, there are many parts to be discarded, and there are many post-processes such as electrode attachment and polarization)
3) There is a bonding process of the piezoelectric element (Because motor performance is greatly affected by the quality of bonding, great care is taken in cleaning the bonding surface, surface accuracy, bonding conditions, etc.)
Etc.
[0007]
Instead, as shown in FIG. 8, a rod-shaped vibration wave motor that is advantageous in terms of cost has been proposed.
[0008]
In this vibration wave motor, a plurality of PZTs 3 and a power supply electrode plate are sandwiched between a first elastic body 1 and a second elastic body 2 having a hole portion coaxial with an outer diameter at the center portion, and the holes By screwing the male threaded portion of the shaft 5 that penetrates the shaft 5 into the inner threaded portion 1e of the elastic body 1, and tightening the

elastic bodies

1 and 2 interposing the PZT3 or the like with the head of the shaft 5, the Langevin A mold vibrator is formed.
[0009]
On the other hand, around the shaft 5, a gear 8 that is rotatably supported by a ball bearing 10, a rotor 8 that engages with a gear 11 and abuts against a spring case 9 in a thrust direction, a spring case 9 that includes a pressure spring 14, and the like. 11, a motor mounting flange 12 on which the ball bearing 10 is mounted is disposed, and the motor mounting flange 12 is fixed by a nut member 13. In the rotor 8, the spring force of the pressure spring 14 is transmitted through the spring case 9, and comes into pressure contact with the driving surface of the elastic body 1. The rotational force is transmitted to the gear 11 and output to the outside.
[0010]
When an alternating signal which is a drive signal, for example, a frequency voltage, is applied to the PZT 3, a drive wave is formed on the drive surface of the first elastic body 1 by bending vibration, and the rotor 8 is frictionally driven by this drive wave. .
[0011]
The rod-like vibration wave motor shown in FIG. 8 can be reduced in diameter (because piezoelectric elements can be stacked so that input power can be input even if the motor is reduced in diameter). In fact, the cost has been significantly reduced compared to the vibration wave motor of the type shown in FIG.
[0012]
However, the cost is several times higher than that of a small electromagnetic motor when compared with the same level of output, and as long as the characteristics of a vibration wave motor (for example, quietness, direct drive, holding power, etc.) can be fully utilized. It is the fact that it is adopted only in the selected field.
[0013]
Therefore, the present inventors have proposed a motor having the structure shown in FIG. 7 in order to further reduce the cost. The structure of the vibration wave motor shown in FIG. 7 is different from the structure of FIG. 8 in the structure and shape of the vibrator and the shaft. That is, in the vibration wave motor of FIG. 7, the first elastic body 1 and the second elastic body 2 are provided with a hole penetrating the central portion of these members, and the flange provided on the shaft 5. The first and second

elastic bodies

1 and 2 and the piezoelectric element 3 are sandwiched between the part 5a and the nut 6 with a predetermined pressure.
[0014]
In this way, the screw portion provided in the first elastic body in FIG. 8 can be eliminated, and the shape of the shaft can be made into a shape that can be easily processed with mass productivity such as header processing (the maximum diameter and the minimum diameter of the shaft). As a result, the cost can be considerably reduced compared to the structure of FIG.
[0015]
These members 1 to 4 are loosely fitted so that they can be easily engaged with the shaft in consideration of assembly, and the outer diameters are aligned with a jig or the like. Has the same degree of coaxiality.
[0016]
However, if the hole of the first elastic body and the shaft portion 5b of the shaft 5 have backlash, when the vibrator vibrates, the shaft and the first elastic body are slightly relative to each other. Since the displacement occurs, there is a problem that a friction loss occurs between the flange 5a of the shaft and the contact surface 1b of the first elastic body, and the motor performance is deteriorated.
[0017]
An object of the present application is to further improve the characteristics of a vibration type actuator such as a rod-type vibration wave motor which is reduced in cost.
[0018]
[Means for Solving the Problems]
The vibration type actuator according to the present invention includes an elastic body having a hole portion through which a fastening shaft member passes and a electromechanical energy conversion element at a center portion, a flange portion provided on the shaft member, and the shaft It is screwed to the member, the fastening member provided at a position facing the flange portion, the said elastic body electro - in the vibration type actuator having a vibrating body and integrated with sandwiching the mechanical energy conversion element from both sides , using the pressure due to the fastening operation of the fastening member, plastic deformation in a part of the flange portion abutting the shaft receiving surface of the elastic body, or a hole portion of the elastic body causing plastic flow The elastic body and the shaft member are coupled together by being inserted between the shaft member and the shaft member.
[0021]
Here, it is possible to the shaft receiving surface of the elastic member, provided with a protruding portion for plastic deformation or plastic flow by receiving the pressing force from the flange portion. In this case, it is possible to cause plastic deformation or plastic flow in a part of the shaft receiving surface by crushing the protrusion by the fastening operation.
[0022]
Further, the boundary portion between the through portion that penetrates the flange portion and the hole portion in the shaft member, and a curved surface having a first radius of curvature, the end portion of the shaft receiving surface of the elastic body of the hole the ridge of the surface, it can be said shaft the small chamfered portion than curved, or the first curvature corner portion having a smaller second radius of curvature than the radius of the member. In this case, it is possible to cause plastic deformation or plastic flow in a part of the shaft receiving surface by crushing the ridge portion by the fastening operation.
[0024]
The method of assembling the vibration type actuator according to the present invention includes an elastic body having a hole portion through which a shaft member for fastening passes , and an electromechanical energy conversion element arranged at the center portion, and a flange portion provided on the shaft member, , it is screwed to the shaft member, the fastening member provided at a position facing the flange portion, the elastic member and the electro - having a vibration body which is integrated with sandwiching the mechanical energy conversion element from both sides vibrations In the method of assembling the mold actuator, the shaft member is passed through the respective holes of the elastic body and the electromechanical energy conversion element, and the tightening force of the fastening member with respect to the shaft member is used. Holes in the elastic body by causing plastic deformation or plastic flow in a part of the shaft receiving surface in contact with the flange portion Said By enter between the shaft member, thereby coupling the resilient member and the shaft member and the.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
1 and 2 show a first embodiment of the present invention.
[0026]
FIG. 1 shows a cross-sectional view of a rod-like vibration wave motor as a vibration type actuator according to the first embodiment of the present invention, and FIG. 2 shows a shaft on the contact surface 1b of the first elastic body 1 with the shaft. The enlarged view of the projection part provided so that it may plastically deform when tightening is shown.
[0027]
A shaft in which the laminated PZT 3 and the feeding flexible cable 4 are sandwiched between the first elastic body 1 and the second elastic body 2 having a hole coaxial with the outer diameter at the center, and the holes are penetrated. The Langevin type vibrating body is formed by tightening the members 1 to 4 with the flange portion 5 a and the nut 6. In addition, a friction ring 7 (SUS420J2 quenching product) is joined to the upper portion of the first elastic body 1 in the figure by an adhesive.
[0028]
On the other hand, the aluminum rotor 8 is anodized, and a cylinder portion 8a for guiding the coil spring 14 and a flange portion 8b for receiving the spring are integrally provided below the cylinder portion 8a. The coil spring 14 is sandwiched and compressed between the flange portion 8 b of the rotor 8 and the gear 11, and presses the rotor 8 against the friction ring 7 of the vibrating body against the gear 11.
[0029]
The gear 11 is positioned in the thrust direction by a motor mounting flange 12 positioned by a positioning step 5 e provided on the shaft 5 and a nut 13 for fixing the motor mounting flange 12, and the motor mounting flange 12. The outer diameter of the cylindrical portion and the inner diameter of the gear 11 are engaged with each other without any play, and the gear 11 is rotatably supported.
[0030]
In the driving of the vibration wave motor having the above-described configuration, when a two-phase alternating signal having a phase shift from a power supply (not shown) is applied to the laminated PZT 3, bending vibration in two directions with respect to the longitudinal direction of the shaft 5 is excited by the vibrating body. The vibrator performs a jump rope motion. At this time, elliptical vibration occurs on the sliding surface of the friction ring, whereby the rotor 8 and the gear 11 rotate together. The rotor 8 is provided with two grooves (not shown) in the radial direction, and the two protrusions (not shown) provided on the gear 11 are fitted with no looseness. Is transmitted to the gear 11 without loss.
[0031]
FIG. 2 shows an enlarged cross-sectional view of the shape of the engaging portion with the shaft of the first elastic body 1 in the portion A of FIG. FIG. 2A shows a shape before the shaft 5 is tightened.
[0032]
On the contact surface 1b of the elastic body 1 with respect to the flange portion 5a of the shaft 5, a protruding portion 1c protruding in the thrust direction of the shaft is provided on the inner peripheral surface side.
[0033]
The diameter of the shaft portion 5b of the shaft 5 is set to a minus tolerance of about 0 to 0.04 mm (the unit is expressed in mm hereinafter) from the diameter of the center hole 1a of the first elastic body 1, and can be easily assembled. The shaft can be inserted into the first elastic body 1. In the present embodiment, the outer diameter φD ₂ of the shaft portion 5b of the shaft 5 is set as follows.
[Outside 1]

[0035]
The inner diameter φD ₁ of the hole 1 a of the first elastic body 1 is
[Outside 2]

[0037]
Set to.
[0038]
Further, the boundary portion 5c between the flange portion 5a and the shaft portion 5b of the shaft 5 has a curvature radius R of about 0.2.
[0039]
When the vibrating body is assembled, the shaft 5 is inserted into the center through hole of the first elastic body 1, the laminated PZT 3, the flexible 4, and the second elastic body 2, and the members 1 to 4 are tightened by the nut 6. 2 is pressed against the elastic body 1 in the direction B in FIG. 2A, and the shaft flange 5a crushes the protrusion 1c provided on the contact surface 1b of the first elastic body 1, and the surplus wall is plastically flowed. As shown by the oblique lines in FIG. 2B, the plastic flow portion 1c ′ fills the gap between the shaft and the first elastic body, so that the shaft portion 5b in the vicinity of the flange portion 5a of the shaft 5 The vicinity of the contact surface 1b of the elastic body 1 is integrally coupled without play. For this reason, even when bending vibration is excited in the vibrating body, the flange portion 5a and the shaft portion 5b of the shaft 5 and the contact surface 1b of the elastic body 1 and the protruding portion 1c cause sliding friction relatively. Therefore, vibration loss (internal loss) of the vibrating body can be minimized, and good vibration characteristics and motor performance can be obtained.
[0040]
In addition, although the protrusion part 1c shown to (a) of FIG. 2 makes the slope on the inner peripheral side a gentle slope, and the slope on the outer peripheral side is a steep slope, as shown in FIG. The inner peripheral surface may be a vertical surface and the outer peripheral surface may be a slope.
[0041]
(Second Embodiment)
3A to 3C show a second embodiment of the present invention.
[0042]
FIG. 3A shows a chamfered portion 1d that is chamfered at the boundary between the inner peripheral surface 1a of the through hole of the first elastic body 1 and the contact surface 1b. It is smaller than R (radius) of the R portion 5c of the shaft 5. This is because when the chamfered amount of the chamfered portion 1d is larger than the radius R of the R portion 5c, the chamfered portion 1d does not move even if the flange portion 5a of the shaft 5 hits the abutting surface 1b as shown in FIG. Since it does not hit the flange portion 5a, the shaft portion 5b, and the R portion 5c of the shaft 5, a part of the material of the elastic body 1 is plastically flowed so that the shaft portion 5b and the inner peripheral surface 1a of the through hole of the elastic body 1 This is because the backlash cannot be filled.
[0043]
As shown in FIG. 3A, when the shaft 5 is not tightened, the chamfered portion 1d abuts against the R portion 5c of the shaft 5, and the abutting surface 1b and the chamfered portion 1d are not in contact with the shaft 5. When the shaft 5 is inserted and a tightening force is applied, the shaft 5 moves in the direction of arrow B with respect to the elastic body 1, and the flange portion 5a of the shaft 5 and the contact surface 1b of the elastic body 1 are in close contact with each other. Therefore, the chamfered portion 1d is crushed by the R portion 5c of the shaft 5, the surplus portion of the shaded portion 1e flows into the shaded portion 1f, and the shaft 5 and the elastic body 1 enter the through hole of the elastic body 1. The parts 1f are integrally coupled.
[0044]
(Third embodiment)
FIG. 4 shows a third embodiment.
[0045]
The present embodiment is an example in which the chamfered portion 1d provided in the second embodiment is further reduced and the chamfering amount is substantially zero (the chamfered portion 1g) . In this case, the amount to be crushed by the flange portion 5a and the R portion 5c of the shaft 5 increases, which is effective when there is a large amount of play due to the set tolerance between the shaft 5 and the elastic body 1.
[0046]
(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the present invention.
[0047]
In the present embodiment, another member 15 that easily undergoes plastic deformation (or plastic flow) is provided at the corner 1 g of the first elastic body 1. In the first to third embodiments described above, the vibration characteristics are good, and brass or aluminum is used as a material that is partly plastically flowable by the shaft tightening force. However, in this embodiment, an elastic body is used. As a material 1, a hard material such as stainless steel or iron is used, and an appropriate separate member (different material) 15 is provided in a portion to be plastically deformed, and the same effects as those of the first to third embodiments described above are provided. Is.
[0048]
The material of the separate member 15 may be brass, aluminum, a metal such as zinc or lead, or a polymer compound having a high Young's modulus to some extent and a low vibration damping.
[0049]
( Reference embodiment)
FIG. 6 shows a fifth embodiment of the present invention.
[0050]
In each of the above-described embodiments, an indirect engagement method is employed in which the protrusion is plastically deformed by the pressure applied in the fastening operation. However, in the present embodiment, the first elastic body 1 and the shaft 5 are used. Such as press-fitting, shrink fitting, or cold fitting, and directly engaging with the shaft member without looseness by directly receiving the pressurizing force associated with the fastening operation. I am trying to configure it.
[0051]
Although not shown in the drawing, the shaft portion 5b of the shaft 5 may be knurled to facilitate the press-fitting.
[0052]
【The invention's effect】
According to the present invention, the friction loss (internal loss of the vibrating body) generated between the shaft member and the elastic body at the time of vibration excitation is drastically reduced even in the structure in which the vibration body in the vibration type actuator is designed to reduce the cost. Therefore, an efficient vibration type actuator can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a rod-shaped vibration wave motor according to first to fifth embodiments to which the present invention is applied.
2A and 2B are partial enlarged cross-sectional views of a portion A showing an assembled state of a vibrating body in the vibration wave motor of FIG. 1, and FIG. 2C is a partial cross-sectional view showing a modification of a protruding portion.
FIGS. 3A to 3C are partial enlarged views of part A of FIG. 1 in a second embodiment of a rod-like vibration wave motor to which the present invention is applied;
4 is a partially enlarged view of part A in FIG. 1 showing a third embodiment of the present invention.
FIG. 5 is a partially enlarged view of part A in FIG. 1 showing a fourth embodiment of the present invention.
FIG. 6 is an enlarged view of a part A showing a reference embodiment in the present invention.
FIG. 7 is a cross-sectional view of a conventional rod-shaped Langevin type vibration wave motor.
FIG. 8 is a cross-sectional view of another conventional rod-shaped Langevin type vibration wave motor.
FIG. 9 is a cross-sectional view of a conventional annular vibration wave motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st elastic body 2 ... 2nd elastic body 3 ... Laminated PZT
4. Flexible (flexible printed wiring board)
5 ... shaft 6 ... nut 7 ... friction ring 8 ... rotor 9 ... spring case 10 ... ball bearing 11 ... gear 12 ... vibrating wave motor flange 13 ... nut 14 ... spring 15 ... plastic deformation member 20 ... vibrating body 21 ... rotor 22 ... Shaft 23 ... Pressure spring 24 ... Vibration wave motor cover

Claims

An elastic body having an aperture through which a fastening shaft member passes, and an electromechanical energy conversion element are arranged at the center, and a flange portion provided on the shaft member is screwed to the shaft member. In a vibration type actuator having a vibration body integrated by sandwiching the elastic body and the electromechanical energy conversion element from both sides by a fastening member provided at a position opposite to
Using the pressure applied by the fastening operation of the fastening member, the elastic body is plastically deformed by crushing a protrusion provided on a part of the shaft receiving surface that contacts the flange portion of the elastic body. gap between said part of the elastic body allowed to enter between the shaft member and the hole of the elastic body, the injected part in the hole of the shaft member and the hole of the elastic body Te The vibration type actuator is characterized in that the elastic body and the shaft member are joined without being loosened by filling a gap .

An elastic body having an aperture through which a fastening shaft member passes, and an electromechanical energy conversion element are arranged at the center, and a flange portion provided on the shaft member is screwed to the shaft member. In a vibration type actuator having a vibration body integrated by sandwiching the elastic body and the electromechanical energy conversion element from both sides by a fastening member provided at a position opposite to
A boundary portion between the flange portion and the penetrating portion penetrating the hole portion in the shaft member is a curved surface having a first radius of curvature, and an end portion of the shaft receiving surface of the elastic body and a surface of the hole portion A chamfered portion smaller than the curved surface of the shaft member or a corner portion having a radius of curvature smaller than the first radius of curvature,
By crushing the ridge portion by the fastening operation by the fastening member, plastic deformation is caused in a part of the shaft receiving surface, and a part of the elastic body is placed between the hole of the elastic body and the shaft member. The elastic body and the shaft member are connected without play by filling the gap between the hole portion of the elastic body and the portion of the shaft member inserted into the hole portion. The vibration type actuator according to claim 1.

An elastic body having an aperture through which a fastening shaft member passes, and an electromechanical energy conversion element are arranged at the center, and a flange portion provided on the shaft member is screwed to the shaft member. In a method of assembling a vibration type actuator having a vibration body integrated by sandwiching the elastic body and the electromechanical energy conversion element from both sides by a fastening member provided at a position opposite to
Using the pressure applied by the fastening operation of the fastening member, the elastic body is plastically deformed by crushing a protrusion provided on a part of the shaft receiving surface that contacts the flange portion of the elastic body. A gap between the hole of the elastic body and a portion of the shaft member inserted into the hole by allowing a part of the elastic body to enter between the hole of the elastic body and the shaft member. A method for assembling a vibration type actuator, wherein the elastic body and the shaft member are coupled without play by filling a gap.

  An elastic body having an aperture through which a fastening shaft member passes, and an electromechanical energy conversion element are arranged at the center, and a flange portion provided on the shaft member is screwed to the shaft member. In a method of assembling a vibration type actuator having a vibration body integrated by sandwiching the elastic body and the electromechanical energy conversion element from both sides by a fastening member provided at a position opposite to
  A boundary portion between the flange portion and the penetrating portion penetrating the hole portion in the shaft member is a curved surface having a first radius of curvature, and an end portion of the shaft receiving surface of the elastic body and a surface of the hole portion A chamfered portion smaller than the curved surface of the shaft member, or a corner portion having a radius of curvature smaller than the first radius of curvature,
  By crushing the ridge portion by the fastening operation by the fastening member, plastic deformation is caused in a part of the shaft receiving surface, and a part of the elastic body is placed between the hole of the elastic body and the shaft member. The elastic body and the shaft member are coupled without play by filling the gap between the hole of the elastic body and the portion of the shaft member inserted into the hole. A method for assembling the vibration actuator according to claim 3.