Piezoelectric ring-morph actuators for valve application

This paper presents piezoelectric ring-morph actuators designed to produce a large flexural displacement for valve actuation application. The ring-shaped piezoelectric plate in the actuator produces a radial contraction or expansion and causes the center part of the metal disc to generate a large flexural displacement. The PZT ring creates a space under the metal disc which permits it to bend with a curvature larger than that of the conventional bimorph in the axis direction of the ring-morph when the PZT ring under the metal disc contracts. A prototype with diameter of 25.4 mm and thickness of 0.55 mm could produce a total stroke (static displacement) of over 130 mum under a driving voltage of +/-300 V and a load of 2 N. The maximum generative force of ring-morph actuator was about 30 N.