PROBLEM TO BE SOLVED: To attain reciprocating rotational motion of an electric toothbrush or similar without employing a drive transmission mechanism as a separate entity from a drive source.SOLUTION: An actuator includes a fixed body 110 comprising an outer yoke 140 having inner wall surfaces that respectively oppose the magnetic pole surfaces of unlike poles of a magnet 150 with a predetermined gap therebetween. A coil 122 is arranged to encircle the magnet 150 between the magnetic pole surfaces of the unlike poles of the magnet 150 and the inner wall surfaces of the outer yoke 140 that respectively oppose the magnetic pole surfaces of the unlike poles, and this coil 122 is movably supported as a moving body 120 by way of an elastic member 130 fastened to the fixed body 110. The reciprocating rotational motion of the moving body 120 is afforded by the supply of an alternating current of a frequency approximately equivalent to the resonant frequency of the moving body 120 from an alternating current supply 180 to the coil 122.COPYRIGHT: (C)2010,JPO&INPIT【課題】電動歯ブラシ等の往復回転運動を、駆動源とは別体の駆動伝達機構を用いることなく実現すること。【解決手段】固定体110は、マグネット150において極の異なる磁極面にそれぞれ所定間隔を空けて対向する内壁面を有するアウターヨーク140を有する。マグネット150において極の異なる磁極面と、極の異なる磁極面のそれぞれと対向するアウターヨーク140の内壁面との間に、マグネット150を周回するコイル122が配置され、このコイル122は可動体120として固定体110に取り付けられる弾性部材130を介して可動自在に支持される。コイル122に、交流供給部180から、可動体120の共振周波数に略等しい周波数の交流が供給されることによって、可動体120は往復回転運動を行う。【選択図】図3
