Study on micro engines-miniaturizing Stirling engines for actuators and heatpumps

The authors present micro-Stirling engines as a new potential field of micromachine study. The micro-Stirling engine is defined as a miniature Stirling engine, smaller than a few cubic centimeters. The purpose of this study is to establish the design concept and to realize a microactuator and a microheatpump. By applying dimensional analysis and computer simulation, the authors investigated how design parameters change when the engine size becomes smaller. A micro-Stirling engine of about 0.05 cm³ in a piston swept volume was realized. The output power is about 10 mW for 10 Hz vibration. Problems of miniaturizing the engines to the size of a few cubic millimeters are discussed