DISPLACEMENT CONTROL MECHANISM USING PIEZOELECTRIC ELEMENT

摘要

PURPOSE:To realize the displacement control at a high speed and with high accuracy by using a piezoelectric element as a displacement source. CONSTITUTION:When a spool 18 of a spool valve 2 is driven, the voltage is first applied to a piezoelectric element 3 via a drive circuit 4. Thus the element 3 contracts to pull a 1st shift wall 15 and to expand a 1st bellows 14 and there fore a 2nd chamber 13 contracts for the balanced pressure. A 2nd shift wall 17 moves back with the contraction of the chamber 13 and this movement of the wall 17 drives the spool 18. The diameter of a 2nd bellows 16 is smaller than that of the bellows 14 and therefore the displacement of the bellows 14 is enlarged at the bellows 16. Thus, it is possible to perform the displacement control at a high speed and with high accuracy.