Motion and Torque Analyses of Swiss Lever Escapement Mechanism for Energy Harvesting Application

Piezoelectric energy harvesting (PEH) leverages the piezoelectric effect to convert mechanical strain into electrical energy. Its high output voltage, low output current, and potential for miniaturization make it an attractive solution to powering micropower generation sensors and devices. In this study, we investigate the integration of the Swiss lever escapement mechanism with PEH to improve energy conversion efficiency under low-frequency conditions. On the basis of motion and torque analyses of escapement mechanisms, strategies were developed for optimal excitation state and design parameters, including hairspring stiffness, applied torque, and moment of inertia, which were identified as the critical factors affecting torque variations. COMSOL Multiphysics^® simulations demonstrated that the proposed system achieves stable power outputs of 86.8, 15.3, and 0.27 μW when the balance wheel, escape wheel, and pallet fork were used as excitation sources, respectively. Furthermore, the average power density of 2.245 μW/cm³ obtained by the balance wheel excitation under the optimal state shows considerable opportunity and potential for practical applications. This work provides a foundation for the further optimization of escapement mechanisms and piezoelectric energy harvesters to enhance sustainability and performance.