Principle and manufacture of a new type of torque sensor based on the torsional effect of a piezoelectric quartz disc

Abstract

This paper mainly investigates the theoretical foundation of a new-type torque sensor (namely, the torsional effect of a piezoelectric quartz disc), the design and calibration of the torque sensor and its engineering application. By using the theory of anisotropic elasticity and Maxwell electromagnetism, the torsion stress and the distribution of bound volume and surface charge densities of a piezoelectric quartz disc are calculated, and then by the finite element method the polarized electric field is simulated. The results show that the distributions of the potential and the electric field intensity in the quartz disc are both antisymmetric with respect to the y-axis. Based on the torsional effect, a new type of torque sensor is designed. The outstanding feature of the torque sensor, in contrast to other types of quartz torque sensor, is that the torque sensor adopts a torsional effect, rather than a shear effect. Only three Y0°-cut discs are used in the torsion quartz measuring cell of the torque sensor. After static and dynamic calibrations, the torque sensor has fully reached the dynamometer standard stipulated by CIRP-STCC. Finally, a drilling experiment is performed to test the application performance of the torque sensor. The experimental results prove that the theoretical analyses and design of the torque sensor are rational. The new type of torque sensor is the subject of an application for a Chinese Invention Patent, Application Number: 03133521.7.