| 摘要 |
PURPOSE:To obtain the large displacement of a nozzle flapper, by driving electrostriction elements by an AC signal, whose frequency is approximately equal to the mechanical resonant frequency of the electrostriction elements and whose amplitude is changed. CONSTITUTION:An oscillator 4 outputs a triangular wave whose frequency is approximately equal to the mechanical resonant frequencies of the electrostriction elements 6a and 6b of the nozzle flapper 5. The amplitude of said triangular wave is changed in response to an input voltage Vi. When the input voltage Vi is increased, the vibrating width of the nozzle flapper 5 is increased, and the ratio of completely closed time of the nozzle 12 is increased. when the ratio of the completely closed time of the nozzle 12 is increased, the back pressure of the nozzle is increased, and the output pnuematic pressure of a pilot valve is increased accordingly. The output pneumatic pressure from the pilot valve 10 is guided out of an outut port 13 as an output pressure, also applied to a pressure sensor 14, and fed back to an operation amplifier 3 of a PI regulator 2. |
