200915712 九、發明說明： 【發明所屬之技術領域】 本發明係有關於一種振動致動器及其驅動方法，特別 是有關於一種使振子產生超音波振動，以使轉子旋轉之振 動驅動器及其驅動方法。 【先前技術】 近年來，提出利用超音波振動，使轉子旋轉之振動驅 動器’並予以實用化。此振動驅動器係使用壓電元件，使 定子表面產生橢圓運動或行進波，藉由使定子加壓接觸轉 子’透過該等兩者間之摩擦力，使轉子移動。 例如’專利文獻1揭示一種振動驅動器，其係以振動 體激發定子X、Y、Z三方向之振動，藉此，使接觸定子之 轉子於3方向移動者。振動體具有激發Z方向之縱振動之 第1壓電元件、激發X-Z平面之彎曲振動之第2壓電元件 及Y-Z平面之彎曲振動之第3壓電元件，對該等第1〜第3 壓電元件施加接近振動體之共振頻率之單一頻率之交流電 壓，激發各自之振動。 專利文獻1 :日本專利公開公報平1 1 -22089 1號 【發明內容】 然而’在實際之振動體，由於一般X、γ、Z三方向之 共振頻率不一致而互異，故當在三方向以共通之單一頻率 驅動第1〜第3壓電元件時，於三方向之旋轉軸產生錯位， 正確地移動控制轉子非易事。 本發明係爲解決此種問題點而完成者，其目的在於提 200915712 供一種在旋轉軸不產生錯位，可正確地移動控制轉 動驅動器及其驅動方法。 本發明之振動驅動器係包含有轉子、振子、使 子對前述振子壓接之預壓機構、藉由使前述振子 動’而讓前述轉子環繞至少1個旋轉軸旋轉之驅動 前述驅動電路係針對對各旋轉軸把依據使前述轉子 需之至少2方向之各共振頻率所設定之頻率作爲對 轉軸之驅動頻率，以驅動前述振子》 本發明之振動驅動器之驅動方法係在轉子對振 之狀態，使前述振子產生振動，藉此，使前述轉子 少1個旋轉軸旋轉；針對各旋轉軸，係把依據使前 旋轉所需之至少2方向之各共振頻率所設定之頻率 前述旋轉軸之驅動頻率，以驅動前述振子。 [發明效果] 根據本發明，由於針對各旋轉軸把依據使前述 轉所需之至少2方向之各共振頻率設定之頻率作爲 旋轉軸之驅動頻率，故可使旋轉軸不產生錯位而正 動控制轉子。 【實施方式】 以下，依附加圖式，說明本發明之實施形態。 第1實施形態 於第1圖顯示本發明實施形態之振動驅動器。 塊1與定子2間夾持振動體3,藉此，形成約呈圓柱 之振子4。在定子2之與振動體3接觸之面的相反側 子之振 前述轉 產生振 電路； 旋轉所 前述旋 子加壓 環繞至 述轉子 作爲對 轉子旋 對前述 確地移 於基部 狀外形 形成有 200915712 凹部5,於此凹部5內收容約呈球體狀轉子6的大約下半部。 於定子2之上部配置支撐構件7。此支撐構件7具有固 定於定子2上面之環狀部8、從環狀部8延伸至上方之倒L 字形角部9，於角部9之前端支撐預壓部1 〇。 在此，爲方便說明，將從基部塊1朝定子2之振子4 之中心軸規定爲Z軸，X軸在對Z軸垂直的方向上延伸，Y 軸相對於Z軸與X軸垂直地延伸。 預壓部1 0與屬轉子6之+Z軸方向最高點之頂點附近 f 接觸。支撐構件7之角部9具彈性，藉此，預壓部10加壓 至轉子6，對轉子6施與-Z軸方向之預壓。 如第2圖所示，預壓部1 0具有凹狀圓錐面形狀之預壓 ' 面1 1，此預壓面1 1與轉子6之頂點附近接觸。 又，基部塊1與定子2藉由通過振動體3內之連結螺 桿1 2相互連結。 定子2之凹部5由具有比轉子6直徑小之內徑之小徑 部1 3及具有比轉子6直徑大之內徑之大徑部1 4構成，於 該等小徑部13及大徑部14之分界部形成位於XY平面上之 環狀段差1 5。轉子6以抵接此凹部5內之段差1 5之狀態呈 可旋轉地支撐著。 此外，基部塊1及定子2分別由杜拉錦形成，轉子6 使用鋼球。 振動體3係使定子2產生超音波振動，而使轉子6環 繞X、Y、Z三軸旋轉者，具有分別位於XY平面上，且相 互重疊之平板狀第1〜第3壓電元件部31〜33。該等第1 200915712 〜第3壓電元件部3 1〜3 3分別電性連接於驅動電路1 6。 具體言之，如第3圖所示，第1壓電元件部31具有依 序重疊具圓板形狀之電極板3 1 a、壓電元件板3 1 b、電極板 31c、壓電元件板31d及電極板31e之構造。同樣地，第2 壓電元件部32具有依序重疊具圓板形狀之電極板32a、壓 電元件板32b、電極板32c、壓電元件板32d及電極板32e 之構造，第3壓電元件部33具有依序重疊具圓板形狀之電 極板3 3 a、壓電元件板3 3 b、電極板3 3 c、壓電元件板3 3 d 及電極板3 3 e之構造。該等壓電元件部3 1〜3 3以藉由絕緣 片3 4〜3 7與定子2及基部塊1相互絕緣之狀態配置。 如第4圖所示，第1壓電元件部3 1的一對壓電元件板 3 1 b及3 1 d極化成在Y軸方向分割爲二的部份相互具有反 極性，分別於Z軸方向（厚度方向）進行膨脹與收縮之相 反變形動作，壓電元件板31b與壓電元件板31d配置成可 相互翻轉。 第2壓電元件部32的一對壓電元件板32b及32d極化 成在不分割爲二的情形下，全體於Z軸方向（厚度方向） 進行膨脹或收縮之變形動作。壓電元件板3 2b與壓電元件 板32d配置成可相互翻轉。 第3壓電元件部33的一對壓電元件板33b及33d極化 成於X軸方向分割爲二個部份相互具反極性，於各Z軸方 向（厚度方向）進行膨脹或收縮之相反之變形動作，壓電 元件板33b與壓電元件板33d配置成可相互翻轉。 配置於第1壓電元件部3 1的兩面部份之電極板3 1 a及 200915712 31e、配置於第2壓電元件部32的兩面部份之電極板32a 及32e、配置於第3壓電元件部33的兩面部份之電極板33a 及3 3 e分別電性連接。又，配置於第1壓電元件部3 1的一 對壓電元件板3 1 b及3 1 d間之電極板3 1 c、配置於第2壓電 元件部32的一對壓電元件板32b及32d間之電極板32c、 配置於第3壓電元件部3 3的一對壓電元件板3 3 b及3 3 d間 之電極板3 3 c分別電性連接於驅動電極1 6。 如第5圖所示，驅動電路1 6具有設定使轉子6環繞X 軸旋轉時之驅動頻率Π之X軸頻率設定部161、設定使轉 子6環繞Y軸旋轉時之驅動頻率f2之Y軸頻率設定部162、 設定使轉子6環繞Z軸旋轉時之驅動頻率f3之Z軸頻率設 定部163。又，於X軸頻率設定部161連接將驅動頻率Π 之交流電壓輸出至第1壓電元件部31及第2壓電元件部32 之X軸驅動部16 4。同樣地，於Y軸頻率設定部1 6 2連接 將驅動頻率f 2之交流電壓輸出至第2壓電元件部3 2及第3 壓電元件部33之Y軸驅動部165。於Z軸頻率設定部163 連接將驅動頻率f3之交流電壓輸出至第1壓電元件部31 及第3壓電元件部33之Z軸驅動部166。 接著，就此第1實施形態之振動驅動器之動作作說 明。首先，在使振動驅動器運作前，分別測量振子4之X 軸方向、γ軸方向、z軸方向之共振頻率。 舉例言之，對第3壓電元件部33之X軸方方向分割爲 二的一對壓電元件板33b及33d施加一定電壓之交流電， 使施加電壓之頻率在預定之測量範圍內掃瞄，監視此時之 200915712 電流値，電流値最大之頻率成爲在X軸方向之振子4之共 振頻率fx。 同樣地，於第1壓電元件部3 1之Y軸方方向分割爲二 的一對壓電元件板31b及31d施加一定電壓之交流電，使 施加電壓之頻率在預定之測量範圍內掃瞄，監視此時之電 流値，電流値最大之頻率成爲在Y軸方向之振子4之共振 頻率fy。 又，對第2壓電元件部32的一對壓電元件板32b及32d 施加一定電壓之交流電，使施加電壓之頻率在預定之測量 範圍內掃瞄，監視此時之電流値，電流値最大之頻率成爲 在Z軸方向之振子4之共振頻率fz。 此種共振頻率之測量可使用阻抗分析儀進行。以阻抗 分析儀掃瞄電壓之頻率，（阻抗之倒數）最大之頻率亦即 電流値最大之頻率，顯示共振頻率。實際上，於第6圖顯 示以阻抗分析儀測量之頻率特性。從此第6圖可知，X軸 方向之共振頻率fx、Y軸方向之共振頻率fy、Z軸方向之 共振頻率fz不一致，互異。 在此，當對第1壓電元件3丨之電極板31c施加接近振 子4之共振頻率fx、fy、fz之頻率之交流電壓時，第1壓 電元件部3 1的一對壓電元件板3 1 b及3 1 d分割爲二之部份 於Z軸方向反覆交互地膨脹及收縮，而於定子2產生Y軸 方向之之彎曲振動。同樣地，當對第2壓電元件32之電極 板3 2c施加交流電壓時，第2壓電元件部32的一對壓電元 件板32b及32d於Z軸方向反覆膨張及收縮，而於定子2 200915712 產生Z軸方向之縱振動。又，當對第3壓電元件33之電極 板3 3 c施加交流電壓時，第3壓電元件部3 3的一對壓電元 件板33b及33d分割爲二之部份於z軸方向反覆交互地膨 脹及收縮，而於定子2產生X軸方向之之彎曲振動。 是故，當對第2壓電元件部32之電極板3 2c與第3壓 電元件部3 3之電極板3 3 c兩者分別施加相位位移90度之 交流電壓時，組合X軸方向之彎曲振動與Z軸方向之彎曲 振動，於與轉子6接觸之定子2之段差15產生XZ面內之 振動，轉子6藉由摩擦力大致環繞Y軸旋轉。 同樣地，當對第1壓電元件部3 1之電極板3 1 c與第2 壓電元件部3 2之電極板3 2 c兩者分別施加相位位移9 0度 之交流電壓時，組合Y軸方向之彎曲振動與Z軸方向之彎 曲振動，於與轉子6接觸之定子2之段差15產生YZ面內 之振動，轉子6藉由摩擦力大致環繞X軸旋轉。 當對第1壓電元件部31之電極板31c與第3壓電元件 部33之電極板33c兩者分別施加相位位移90度之交流電 壓時’組合X軸方向之彎曲振動與Y軸方向之彎曲振動， 於與轉子6接觸之定子2之段差15產生XY面內之振動， 轉子6藉由摩擦力大致環繞z軸旋轉。 如此，爲使轉子6環繞X軸旋轉，需Y軸方向之彎曲 振動與Z軸方向之縱振動之組合，爲使轉子6環繞Y軸旋 轉’需X軸方向之彎曲振動與Z軸方向之縱振動之組合， 爲使轉子6環繞Z軸旋轉，需X軸方向之彎曲振動與Y軸 方向之彎曲振動之組合。 -11- 200915712 是故’將環繞1個旋轉軸之旋轉所需之2方向之各振 子4之共振頻率中間値作爲對該旋轉軸之驅動頻率。即， 使轉子6環繞X軸旋轉時，令Y軸方向之共振頻率〇與z 軸方向之共振頻率fz之中間値fl=(fy + fz) /2作爲驅動頻 率’使轉子6環繞Y軸旋轉時’令X軸方向之共振頻率fx 與Z軸方向之共振頻率fz之中間値f2= ( fx + fz ) /2作爲驅 動頻率’使轉子6環繞Z軸旋轉時，令X軸方向之共振頻 率fx與Y軸方向之共振頻率fy之中間値f3= ( fx + fy ) /2 作爲驅動頻率。 將如此進行而得之驅動頻率f 1、f 2，f 3分別設定於驅 動電路16之X軸頻率設定部161、Y軸頻率設定部162、z 軸頻率設定部1 6 3。 然後，使旋轉軸6環繞X軸旋轉時，從驅動電路16之 X軸驅動部164對第1壓電元件部31之電極板31c與第2 壓電元件部32之電極板32c兩者分別施加使相位位移90 度之驅動頻率Π之交流電壓。藉此，組合Y軸方向之彎曲 振動與Z軸方向之縱振動，於與轉子6接觸之定子2之段 差15產生YZ面內之橢圓振動，在不產生軸錯位下，轉子 6環繞X軸旋轉。 使旋轉軸6環繞Y軸旋轉時，從驅動電路1 6之Y軸驅 動部165對第2壓電元件部32之電極板32c與第3壓電元 件部33之電極板33c兩者分別施加使相位位移90度之驅 動頻率f2之交流電壓。藉此，組合X軸方向之彎曲振動與 Z軸方向之縱振動，於與轉子6接觸之定子2之段差15產 -12- 200915712 生XZ面內之橢圓振動，在不產生軸錯位下，轉子 Υ軸旋轉。 再者’使旋轉軸6環繞Ζ軸旋轉時，從驅動電j Ζ軸驅動部166對第1壓電元件部31之電極板31c 壓電元件部33之電極板33c兩者分別施加使相位. 度之驅動頻率f3之交流電壓。藉此，組合X軸方向 振動與Y軸方向之彎曲振動，於與轉子6接觸之定 段差15產生XY面內之橢圓振動，在不產生軸錯位 f 子6環繞Z軸旋轉。 如此，將對各旋轉軸X、Y、Z依使轉子6旋轉 2方向之各振動子之共振頻率設定之頻率作爲對 軸之驅動頻率，藉此，在不於旋轉軸產生錯位下， 地移動控制轉子6。 此外’對用以產生環繞1個旋轉軸旋轉所需之 之振動之2個壓電元件部施加使相位位移90度之 壓，但不限於此。惟，爲於定子2之段差15產生效 橢圓振動或圓振動，而使轉子6旋轉移動，宜以2 振動之組合，控制對2個壓電元件部施加之交流電 幅及相位 第2實施形態 於第7圖顯示第2實施形態之振動驅動器之電 此第2實施形態係在上述第1實施形態之振動驅動 於振動體3之第1〜第3壓電元件部31〜33連接共 測量電路1 7 ’於此共振頻率測量電路1 7分別連接驅 6環繞 & 16之 與第3 立移90 之彎曲 子2之 下，轉 所需之 該旋轉 可正確 2方向 交流電 率佳之 方向之 壓之振 系統。 器中， 振頻率 動電路 200915712 16之X軸頻率設定部161、Y軸頻率設定部162、Z軸頻率 設定部1 6 3。 共振頻率測量電路丨7對第1〜第3壓電元件部3 1〜3 3 之各壓電元件板分別施加一定電壓之交流電，在預定之測 量範圍內掃瞄電壓之頻率，監視此時之電流値或導納，從 電流値或最大之頻率測量X軸方向、Y軸方向、Z軸方向 之振子4之共振頻率fx、fy、fz。又，共振頻率測量電路 1 7使所測量之共振頻率fX、fy、f Z分別輸出至X軸頻率設 定部1 6 1、Y軸頻率設定部1 6 2、Z軸頻率設定部1 6 3而設 定。 一般，以轉子6之旋轉，使一些負載移動或驅動時， 由於振子4承受其反作用，故於振子4之共振頻率產生變 化。 是故，以共振頻率測量電路1 7分別測量X軸方向、Y 軸方向、Z軸方向之振動4之共振頻率fx、fy、fz， 更新 驅動電路16之X軸頻率設定部161、Y軸頻率設定部162、 U ζ軸頻率設定部163時，即使振子4之共振頻率產生變化， 大致可即時地掌握其變化，使用正確之共振頻率fx、fy、 fz，驅動第1〜第3壓電元件部31〜33。因而，可更正確 地移動控制轉子。 其他實施形態 在上述第1實施形態及第2實施形態中，對X、Y、Z3 個旋轉軸，將使轉子6旋轉所需之2方向之共振頻率之中 間値爲對其旋轉軸之驅動頻率，不限於此。舉例言之，可 -14- 200915712 合成3方向以上之振動’進行環繞1個旋轉軸之旋轉，此 時，依轉子6之旋轉所需之3方向以上之共振頻率，設定 驅動頻率。又’亦可將位在所有方向之共振頻率之最小値 至最大値間’互異之頻率設定爲各旋轉軸之驅動頻率。再 者’亦可使轉子6環繞某旋轉軸旋轉所需之各頻率間之値 作爲對該旋轉軸之驅動頻率。 此外，在上述第1實施形態及第2實施形態中，例示 了使用第1〜第3壓電元件部31〜33,使轉子6環繞X、Y、 Ζ 3個旋轉軸旋轉者’但不限於此，對僅環繞1個旋轉軸旋 轉或環繞2個旋轉軸旋轉之振動驅動器亦可適用本發明。 當僅環繞1個旋轉軸旋轉時，轉子未必爲球體狀，亦可爲 圓柱形狀。 又，在第1實施形態及第2實施形態中，從略呈球狀 轉子6之頂點附近施與預壓，本發明並非對預壓力之施加 方法作任何限定者。 本發明之振動驅動器可用於機械手臂。 【圖式簡單說明】 第1圖係顯示本發明第1實施形態之振動驅動器之立 體圖。 第2圖係顯示第1實施形態之振動驅動器之截面圖。 第3圖係顯示在第1實施形態使用之振動體結構之部 份截面圖。 第4圖係顯示在第1實施形態使用之振動體之3對壓 電元件板之極化方向的立體圖。 -15- 200915712 第5圖係顯示在第1實施形態使用之驅動電路內部結 構之塊圖。 第6圖係顯示振子之X、Y、Z方向之各共振頻率及使 轉子環繞X軸、環繞Y軸、環繞Z軸旋轉時之各驅動頻率 之圖表。 第7圖係顯示第2實施形態之振動驅動器之電系統之 塊圖。 【主要元件符號說明】200915712 IX. Description of the Invention: [Technical Field] The present invention relates to a vibration actuator and a driving method thereof, and more particularly to a vibration driver for driving a vibrator to generate ultrasonic vibration for rotating a rotor and driving thereof method. [Prior Art] In recent years, a vibration actuator ─ that uses a supersonic vibration to rotate a rotor has been proposed and put into practical use. The vibration driver uses a piezoelectric element to cause an elliptical motion or a traveling wave on the surface of the stator, and the rotor is moved by the frictional force between the two through the stator pressing contact with the rotor. For example, Patent Document 1 discloses a vibration actuator that excites vibrations in three directions of the stators X, Y, and Z by a vibrating body, thereby moving the rotor that contacts the stator in three directions. The vibrating body has a first piezoelectric element that excites longitudinal vibration in the Z direction, a second piezoelectric element that excites bending vibration of the XZ plane, and a third piezoelectric element that bends vibration in the YZ plane, and the first to third pressures are applied thereto. The electrical component applies an alternating voltage of a single frequency close to the resonant frequency of the vibrating body to excite the respective vibrations. Patent Document 1: Japanese Patent Laid-Open Publication No. Hei No. Heisei No. 1-22-22 No. 1 [Summary of the Invention] However, in the actual vibrating body, since the resonance frequencies of the three directions of X, γ, and Z are different from each other, they are different in three directions. When the first to third piezoelectric elements are driven at a single frequency in common, the rotation axes in the three directions are displaced, and it is not easy to accurately control the rotor. The present invention has been made to solve such a problem, and its object is to provide a method for driving a control rotary drive and a driving method thereof without causing misalignment on a rotating shaft. The vibration actuator according to the present invention includes a rotor, a vibrator, and a preloading mechanism that presses the vibrator to the vibrator, and the driving of the rotor is performed by rotating the rotor around at least one rotating shaft. Each of the rotating shafts drives the vibrator according to a frequency set by at least two resonance frequencies required for the rotor as a driving frequency of the rotating shaft. The driving method of the vibrating actuator of the present invention is in a state in which the rotor is vibrated. The vibrator generates vibration, whereby the rotor rotates by one rotation axis, and for each rotation axis, the drive frequency of the rotation axis is set at a frequency set according to each resonance frequency of at least two directions required for the front rotation. To drive the aforementioned vibrator. [Effect of the Invention] According to the present invention, since the frequency at which the respective resonance frequencies of at least two directions required for the rotation are set is the drive frequency of the rotation axis for each rotation axis, the rotation axis can be prevented from being displaced and the forward movement control can be performed. Rotor. [Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. (First Embodiment) A vibration driver according to an embodiment of the present invention is shown in Fig. 1. The vibrating body 3 is sandwiched between the block 1 and the stator 2, whereby a vibrator 4 having a cylindrical shape is formed. The above-mentioned rotation of the opposite side of the surface of the stator 2 in contact with the vibrating body 3 generates a vibrating circuit; the rotation of the aforementioned cyclone is pressed around the rotor as a pair of rotors, and the recess is partially formed in the base shape. 5. The approximately lower half of the spherical rotor 6 is housed in the recess 5. A support member 7 is disposed on the upper portion of the stator 2. This support member 7 has an annular portion 8 fixed to the upper surface of the stator 2, an inverted L-shaped corner portion 9 extending from the annular portion 8 to the upper portion, and a front pressing portion 1 支撑 supported at the front end of the corner portion 9. Here, for convenience of explanation, the central axis of the vibrator 4 from the base block 1 toward the stator 2 is defined as a Z-axis, the X-axis extends in a direction perpendicular to the Z-axis, and the Y-axis extends perpendicularly to the Z-axis and the X-axis. . The preloading portion 10 is in contact with the vicinity of the apex of the highest point in the +Z-axis direction of the rotor 6 . The corner portion 9 of the support member 7 is elastic, whereby the preload portion 10 is pressurized to the rotor 6, and the rotor 6 is biased in the -Z-axis direction. As shown in Fig. 2, the preloading portion 10 has a pre-pressed surface 1 of a concave conical shape, and this pre-compression surface 1 1 is in contact with the vicinity of the apex of the rotor 6. Further, the base block 1 and the stator 2 are coupled to each other by the connecting screw 1 2 in the vibrating body 3. The concave portion 5 of the stator 2 is composed of a small diameter portion 13 having an inner diameter smaller than the diameter of the rotor 6, and a large diameter portion 14 having an inner diameter larger than the diameter of the rotor 6, and the small diameter portion 13 and the large diameter portion are formed in the small diameter portion 13 and the large diameter portion. The boundary portion of 14 forms an annular segment difference 15 in the XY plane. The rotor 6 is rotatably supported in a state of abutting the step 15 in the recess 5. Further, the base block 1 and the stator 2 are respectively formed of Dura brocade, and the rotor 6 is made of a steel ball. In the vibrating body 3, the stator 2 is subjected to ultrasonic vibration, and the rotor 6 is rotated around the X, Y, and Z axes, and the flat first to third piezoelectric element portions 31 are disposed on the XY plane and overlap each other. ~33. The first 200915712 to the third piezoelectric element portions 3 1 to 3 3 are electrically connected to the drive circuit 16 , respectively. Specifically, as shown in Fig. 3, the first piezoelectric element portion 31 has electrode plates 3 1 a having a disk shape in this order, a piezoelectric element plate 3 1 b, an electrode plate 31c, and a piezoelectric element plate 31d. And the structure of the electrode plate 31e. Similarly, the second piezoelectric element portion 32 has a structure in which the electrode plate 32a having the disk shape, the piezoelectric element plate 32b, the electrode plate 32c, the piezoelectric element plate 32d, and the electrode plate 32e are sequentially stacked, and the third piezoelectric element The portion 33 has a structure in which the electrode plate 3 3 a having the disk shape, the piezoelectric element plate 3 3 b, the electrode plate 3 3 c, the piezoelectric element plate 3 3 d , and the electrode plate 3 3 e are sequentially stacked. The piezoelectric element portions 3 1 to 3 3 are disposed in a state in which the stator 2 and the base block 1 are insulated from each other by the insulating sheets 34 to 37. As shown in Fig. 4, the pair of piezoelectric element plates 3 1 b and 3 1 d of the first piezoelectric element portion 31 are polarized so that the portions divided into two in the Y-axis direction have opposite polarities, respectively, on the Z-axis. The direction (thickness direction) is reversed by expansion and contraction, and the piezoelectric element plate 31b and the piezoelectric element plate 31d are disposed to be mutually inverted. The pair of piezoelectric element plates 32b and 32d of the second piezoelectric element portion 32 are polarized so as to be expanded or contracted in the Z-axis direction (thickness direction) without being divided into two. The piezoelectric element plate 32b and the piezoelectric element plate 32d are disposed to be mutually inverted. The pair of piezoelectric element plates 33b and 33d of the third piezoelectric element portion 33 are polarized so as to be divided into two portions in the X-axis direction and have opposite polarities, and are expanded or contracted in the respective Z-axis directions (thickness directions). In the deformation operation, the piezoelectric element plate 33b and the piezoelectric element plate 33d are disposed so as to be mutually inverted. The electrode plates 3 1 a and 200915712 31e disposed on both surfaces of the first piezoelectric element portion 31 and the electrode plates 32a and 32e disposed on both surfaces of the second piezoelectric element portion 32 are disposed on the third piezoelectric layer The electrode plates 33a and 33e of the both surface portions of the element portion 33 are electrically connected, respectively. Moreover, the electrode plate 3 1 c disposed between the pair of piezoelectric element plates 3 1 b and 3 1 d of the first piezoelectric element portion 31 and the pair of piezoelectric element plates disposed on the second piezoelectric element portion 32 The electrode plates 32c between 32b and 32d, and the electrode plates 3 3 c disposed between the pair of piezoelectric element plates 3 3 b and 3 3 d of the third piezoelectric element portion 3 3 are electrically connected to the drive electrodes 16 , respectively. As shown in Fig. 5, the drive circuit 16 has an X-axis frequency setting unit 161 for setting a drive frequency 时 when the rotor 6 rotates around the X-axis, and a Y-axis frequency for setting a drive frequency f2 for rotating the rotor 6 around the Y-axis. The setting unit 162 sets a Z-axis frequency setting unit 163 that drives the drive frequency f3 when the rotor 6 rotates around the Z-axis. Further, the X-axis frequency setting unit 161 is connected to the X-axis driving unit 16 4 that outputs the AC voltage of the driving frequency 至 to the first piezoelectric element portion 31 and the second piezoelectric element portion 32. Similarly, the Y-axis frequency setting unit 1 6 2 is connected to the Y-axis driving unit 165 that outputs the AC voltage of the driving frequency f 2 to the second piezoelectric element portion 3 2 and the third piezoelectric element portion 33 . The Z-axis frequency setting unit 163 is connected to the Z-axis driving unit 166 that outputs the AC voltage of the driving frequency f3 to the first piezoelectric element portion 31 and the third piezoelectric element portion 33. Next, the operation of the vibration driver of the first embodiment will be described. First, the resonance frequency of the vibrator 4 in the X-axis direction, the γ-axis direction, and the z-axis direction is measured before the vibration driver is operated. For example, an alternating current of a constant voltage is applied to the pair of piezoelectric element plates 33b and 33d in which the X-axis direction of the third piezoelectric element portion 33 is divided into two, so that the frequency of the applied voltage is scanned within a predetermined measurement range. When the current voltage of 200915712 is monitored at this time, the frequency at which the current 値 is maximum becomes the resonance frequency fx of the vibrator 4 in the X-axis direction. Similarly, a pair of piezoelectric element plates 31b and 31d which are divided into two in the Y-axis direction of the first piezoelectric element portion 31 are applied with a constant voltage alternating current, and the frequency of the applied voltage is scanned within a predetermined measurement range. The current 値 at this time is monitored, and the frequency at which the current 値 is maximum becomes the resonance frequency fy of the vibrator 4 in the Y-axis direction. Further, an alternating current of a constant voltage is applied to the pair of piezoelectric element plates 32b and 32d of the second piezoelectric element portion 32, and the frequency of the applied voltage is scanned within a predetermined measurement range, and the current 値 at this time is monitored, and the current 値 is maximum. The frequency becomes the resonance frequency fz of the vibrator 4 in the Z-axis direction. Measurement of such a resonant frequency can be performed using an impedance analyzer. The frequency at which the impedance analyzer scans the voltage, the maximum frequency (the reciprocal of the impedance), that is, the frequency at which the current 値 is the maximum, shows the resonance frequency. In fact, Figure 6 shows the frequency characteristics measured with an impedance analyzer. As can be seen from Fig. 6, the resonance frequency fx in the X-axis direction, the resonance frequency fy in the Y-axis direction, and the resonance frequency fz in the Z-axis direction do not coincide with each other. Here, when an alternating voltage of a frequency close to the resonance frequencies fx, fy, and fz of the vibrator 4 is applied to the electrode plate 31c of the first piezoelectric element 3, a pair of piezoelectric element plates of the first piezoelectric element portion 31 3 1 b and 3 1 d are divided into two parts which alternately expand and contract in the Z-axis direction, and the stator 2 generates bending vibration in the Y-axis direction. Similarly, when an alternating voltage is applied to the electrode plate 3 2c of the second piezoelectric element 32, the pair of piezoelectric element plates 32b and 32d of the second piezoelectric element portion 32 are repeatedly expanded and contracted in the Z-axis direction, and are in the stator. 2 200915712 Produces longitudinal vibration in the Z-axis direction. When an alternating voltage is applied to the electrode plates 3 3 c of the third piezoelectric element 33, the pair of piezoelectric element plates 33b and 33d of the third piezoelectric element portion 33 are divided into two in the z-axis direction. The expansion and contraction are alternately performed, and the bending vibration of the X-axis direction is generated in the stator 2. Therefore, when an AC voltage having a phase shift of 90 degrees is applied to both the electrode plate 3 2c of the second piezoelectric element portion 32 and the electrode plate 3 3 c of the third piezoelectric element portion 3 3, the X-axis direction is combined. The bending vibration and the bending vibration in the Z-axis direction generate a vibration in the XZ plane at a step 15 of the stator 2 in contact with the rotor 6, and the rotor 6 rotates substantially around the Y-axis by the frictional force. Similarly, when an alternating voltage of a phase shift of 90 degrees is applied to both the electrode plate 3 1 c of the first piezoelectric element portion 31 and the electrode plate 3 2 c of the second piezoelectric element portion 3 2 , the combination Y The bending vibration in the axial direction and the bending vibration in the Z-axis direction generate a vibration in the YZ plane with a step 15 of the stator 2 in contact with the rotor 6, and the rotor 6 rotates substantially around the X-axis by the frictional force. When an alternating voltage having a phase shift of 90 degrees is applied to both the electrode plate 31c of the first piezoelectric element portion 31 and the electrode plate 33c of the third piezoelectric element portion 33, the bending vibration in the X-axis direction and the Y-axis direction are combined. The bending vibration generates a vibration in the XY plane by the step 15 of the stator 2 in contact with the rotor 6, and the rotor 6 rotates substantially around the z-axis by the frictional force. Thus, in order to rotate the rotor 6 around the X-axis, a combination of the bending vibration in the Y-axis direction and the longitudinal vibration in the Z-axis direction is required to rotate the rotor 6 around the Y-axis, which requires the bending vibration in the X-axis direction and the Z-axis direction. The combination of vibrations, in order to rotate the rotor 6 around the Z axis, requires a combination of bending vibration in the X-axis direction and bending vibration in the Y-axis direction. -11- 200915712 Therefore, the intermediate frequency of the resonance frequency of each of the transducers 4 in the two directions required to rotate around one rotation axis is taken as the driving frequency of the rotation axis. That is, when the rotor 6 is rotated about the X-axis, the middle of the resonance frequency 〇 of the Y-axis direction and the resonance frequency fz of the z-axis direction 値 fl=(fy + fz) /2 as the drive frequency 'rotates the rotor 6 around the Y-axis. When the 'resonance frequency fx in the X-axis direction and the resonance frequency fz in the Z-axis direction 値f2=( fx + fz ) /2 as the driving frequency 'when the rotor 6 rotates around the Z-axis, the resonance frequency in the X-axis direction is made The middle of the resonance frequency fy between fx and the Y-axis direction 値f3=(fx + fy) /2 is used as the driving frequency. The drive frequencies f 1 , f 2, and f 3 thus obtained are set in the X-axis frequency setting unit 161, the Y-axis frequency setting unit 162, and the z-axis frequency setting unit 163 of the drive circuit 16, respectively. When the rotary shaft 6 is rotated about the X-axis, the X-axis drive unit 164 of the drive circuit 16 applies the electrode plate 31c of the first piezoelectric element portion 31 and the electrode plate 32c of the second piezoelectric element portion 32, respectively. The AC voltage that causes the phase to be shifted by 90 degrees. Thereby, the bending vibration in the Y-axis direction and the longitudinal vibration in the Z-axis direction are combined, and the step 15 of the stator 2 in contact with the rotor 6 generates an elliptical vibration in the YZ plane, and the rotor 6 rotates around the X-axis without generating an axial misalignment. . When the rotary shaft 6 is rotated about the Y-axis, the Y-axis drive unit 165 of the drive circuit 16 applies the electrode plate 32c of the second piezoelectric element portion 32 and the electrode plate 33c of the third piezoelectric element portion 33, respectively. The AC voltage of the drive frequency f2 with a phase shift of 90 degrees. Thereby, the bending vibration in the X-axis direction and the longitudinal vibration in the Z-axis direction are combined, and the step of the stator 2 in contact with the rotor 6 produces an elliptical vibration in the XZ plane of -12-200915712, and the rotor is not generated in the axial misalignment. The Υ axis rotates. Further, when the rotary shaft 6 is rotated about the yoke axis, the phase is applied to the electrode plate 31c of the first piezoelectric element portion 31 and the electrode plate 33c of the piezoelectric element portion 33 from the drive electric motor y-axis drive unit 166. The AC voltage of the driving frequency f3. Thereby, the X-axis direction vibration and the bending vibration in the Y-axis direction are combined, and the elliptical vibration in the XY plane is generated in the step 15 contact with the rotor 6, and the axis misalignment f is not generated around the Z-axis. In this manner, the frequency at which the resonance frequencies of the respective vibrators of the rotor 6 are rotated in the two directions of the rotation axes X, Y, and Z is set as the drive frequency of the opposite axis, thereby moving the ground without shifting the rotation axis. The rotor 6 is controlled. Further, the pressure is applied to the two piezoelectric element portions for generating the vibration required to rotate around one rotation axis, and the phase is displaced by 90 degrees, but is not limited thereto. However, in order to generate the effective elliptical vibration or the circular vibration in the step 15 of the stator 2, and to rotate the rotor 6, it is preferable to control the alternating current amplitude and phase applied to the two piezoelectric element portions by the combination of the two vibrations. In the second embodiment, the first to third piezoelectric element portions 31 to 33 of the vibrating body 3 are connected to the common measuring circuit 1 in the second embodiment. 7' The resonance frequency measuring circuit 17 is connected to the bending element 2 of the driving 6 and the 16th vertical movement 90 respectively, and the rotation required for the rotation can be correct in the direction of the alternating current in the 2 direction. system. The X-axis frequency setting unit 161, the Y-axis frequency setting unit 162, and the Z-axis frequency setting unit 163 of the vibration frequency circuit 200915712. The resonance frequency measuring circuit 丨7 applies an alternating current of a constant voltage to each of the piezoelectric element plates of the first to third piezoelectric element portions 3 1 to 3 3 , and scans the frequency of the voltage within a predetermined measurement range to monitor the time. The current 値 or admittance measures the resonance frequencies fx, fy, and fz of the vibrator 4 in the X-axis direction, the Y-axis direction, and the Z-axis direction from the current 値 or the maximum frequency. Further, the resonance frequency measuring circuit 17 outputs the measured resonance frequencies fX, fy, and f Z to the X-axis frequency setting unit 161, the Y-axis frequency setting unit 162, and the Z-axis frequency setting unit 163, respectively. set up. Generally, when the rotor 6 is moved or driven by the rotation of the rotor 6, since the vibrator 4 receives its reaction, the resonance frequency of the vibrator 4 changes. Therefore, the resonance frequency measuring circuit 17 measures the resonance frequencies fx, fy, and fz of the vibrations 4 in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, and updates the X-axis frequency setting portion 161 of the drive circuit 16 and the Y-axis frequency. When the setting unit 162 and the U-axis frequency setting unit 163 change the resonance frequency of the vibrator 4, the change can be grasped substantially instantaneously, and the first to third piezoelectric elements are driven using the correct resonance frequencies fx, fy, and fz. Parts 31 to 33. Thus, the control rotor can be moved more correctly. In the first embodiment and the second embodiment, the middle of the resonance frequency of the two directions required to rotate the rotor 6 for the X, Y, and Z rotating axes is the driving frequency of the rotating shaft. Not limited to this. For example, -14-200915712 can synthesize the vibration in the three directions or more to rotate around one rotation axis. At this time, the drive frequency is set in accordance with the resonance frequency of three or more directions required for the rotation of the rotor 6. Further, the frequency of the minimum 値 to the maximum ’ of the resonance frequencies in all directions may be set as the driving frequency of each of the rotating axes. Furthermore, 値 between the frequencies required for the rotor 6 to rotate around a certain axis of rotation may be used as the driving frequency for the rotating shaft. In the first embodiment and the second embodiment, the first to third piezoelectric element portions 31 to 33 are used to rotate the rotor 6 around the X, Y, and 旋转 three rotation axes, but not limited thereto. Thus, the present invention is also applicable to a vibration driver that rotates only around one rotation axis or rotates around two rotation axes. When rotating only around one axis of rotation, the rotor is not necessarily spherical but also cylindrical. Further, in the first embodiment and the second embodiment, the preload is applied from the vicinity of the vertex of the slightly spherical rotor 6, and the present invention is not limited to the method of applying the pre-pressure. The vibration driver of the present invention can be used for a robot arm. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a vibration actuator according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the vibration driver of the first embodiment. Fig. 3 is a cross-sectional view showing a part of a vibrating body structure used in the first embodiment. Fig. 4 is a perspective view showing a polarization direction of three pairs of piezoelectric element plates of the vibrating body used in the first embodiment. -15- 200915712 Fig. 5 is a block diagram showing the internal structure of the drive circuit used in the first embodiment. Fig. 6 is a graph showing the resonance frequencies of the X, Y, and Z directions of the vibrator and the respective driving frequencies when the rotor is rotated around the X axis, around the Y axis, and around the Z axis. Fig. 7 is a block diagram showing the electric system of the vibration driver of the second embodiment. [Main component symbol description]
1 基部塊 2 定子 3 振動體 4 振子 5 凹部 6 轉子 7 支撐構件 8 環狀部 9 角部 10 預壓部 11 預壓面 12 連結螺桿 13 小徑部 14 大徑部 15 段差 16 驅動電路 -16- 200915712 17 共 振 頻 率 測 量 電路 3 1 第 1 壓 電 元 件 部 3 1a 電 極 板 3 1b 壓 電 元 件 板 3 1c 電 極 板 31d 壓 電 元 件 板 3 le 電 極 板 32 第 2 壓 電 元 件 部 32a 電 極 板 32b 壓 電 元 件 板 32c 電 極 板 32d 壓 電 元 件 板 32e 電 極 板 33 第 3 壓 電 元 件 部 33a 電 極 板 33b 壓 電 元 件 板 33c 電 極 板 33d 壓 電 元 件 板 33e 電 極 板 34 絕 緣 片 35 絕 緣 片 36 絕 緣 片 37 絕 緣 片 161 X 軸 ifcS 頻 率 設 疋 部 -17 200915712 162 Y 軸 頻 率 設 定 部 163 Ζ 軸 ifcS 頻 率 設 定 部 164 X 軸 驅 動 部 165 Υ 軸 驅 動 部 166 Ζ 軸 驅 動 部1 base block 2 stator 3 vibrating body 4 vibrator 5 recess 6 rotor 7 support member 8 annular portion 9 corner portion 10 pre-compression portion 11 pre-compression surface 12 connecting screw 13 small-diameter portion 14 large-diameter portion 15 step difference 16 drive circuit-16 - 200915712 17 Resonance frequency measuring circuit 3 1 1st piezoelectric element portion 3 1a Electrode plate 3 1b Piezoelectric element plate 3 1c Electrode plate 31d Piezoelectric element plate 3 le Electrode plate 32 Second piezoelectric element portion 32a Electrode plate 32b Pressure Electrical component plate 32c Electrode plate 32d Piezoelectric element plate 32e Electrode plate 33 Third piezoelectric element portion 33a Electrode plate 33b Piezoelectric element plate 33c Electrode plate 33d Piezoelectric element plate 33e Electrode plate 34 Insulating sheet 35 Insulating sheet 36 Insulating sheet 37 Insulation sheet 161 X-axis ifcS Frequency setting unit-17 200915712 162 Y-axis frequency setting unit 163 Ζ Axis ifcS frequency setting unit 164 X-axis driving unit 165 轴 Axis driving unit 166 Ζ Axis driving unit