Resonantly driven piezoelectric micropump: Fabrication of a micropump having high power density

Abstract

Abstract As a fluid power source for practical micromachines using fluid power such as in-pipe mobile micromachines, micropumps having high power density are required. In this paper, a piezoelectric micropump using resonance drive is fabricated with the size of φ 9×10 mm. It basically consists of a bellows as a flexible pump chamber, a piezoelectric actuator for oscillating the bellows, and cantilever type of two check valves. An additional mass is attached to the free end of the piezoelectric actuator to enlarge amplitude of the displacement at resonant point. Firstly, through basic experiments using tap water as a working fluid, frequency characteristics and load characteristics of the pressure-dependent flow rate are experimentally investigated with various additional masses and valve thicknesses for stable and high performance. Next, for pumping of fluids having much higher viscosity than tap water, some improvements such as redesign of check valves and an application of a boost pressure are performed. Through basic experiments on pump performances using silicone oil, the effectiveness of those improvements is verified. As a result, the feasibility of the resonantly driven piezoelectric micropump is confirmed.