| 摘要 |
PURPOSE:To efficiently move a movable portion along a drive shaft by providing a movable portion of piezo-electric material temporarily connected to a drive shaft axially vibrating and controlling the timing of a signal applied to the movable portion. CONSTITUTION:A drive shaft 1 having common electrode 11 is reciprocated axially by drive means 2. A movable portion 3 is formed of a ring-like piezo-electric material 31 and an electrode 32 provided on the surface thereof. An input signal e1 and a signal ev relative to the displacement of the drive shaft 1 are applied to a control circuit 4, which thereupon produces an output pulse e0 to between the electrode 11 and an electrode 32. Thus, when the pluse e0 is applied, an electric field is applied to the material 31 to radially contract the drive shaft 1 to couple it by means of electrostrictive effect. Thus, the movable portion 3 moves with the drive shaft 1, and when no pulse 30 is generated, no coupling occurs. Accordingly, it can effectively drive the shaft by controlling the timing of the pulse e0. |
