Element vibrating in two uncoupled modes, and use in vibrating rate gyroscope

摘要

The present disclosure relates to a vibrating element which is planar parallelly to an electrical crystallographic axis of a piezoelectric material such as quartz. The element comprises a beam holding electrodes, a stationary portion rigidly connected to one end of the beam, and a solid portion rigidly connected to the other end of the beam. The structure with facets from the chemical machining of the element has an axis of symmetry parallel to the electrical axis, and the solid portion has a center of gravity on the axis of symmetry. The useful vibration modes of the vibrating element, according to which the solid portion is reciprocatingly rotated about the axis of symmetry and reciprocatingly moved parallel to the plane of the element, are uncoupled. The measurement of an angular speed by a rate gyroscope including said vibrating elements is more precise.

主权项

1. A vibrating element made in a piezoelectric material machinable through a chemical process, having first and second modes of vibration and having a monolithic structure with a material of uniform thickness and being planar parallelly to a crystallographic plane XY of the material, which includes an electric crystallographic axis X and a mechanical crystallographic axis Y, and including a single substantially parallelepiped beam supporting electrodes configured to take part in one of the two modes of vibration; said beam comprising a longitudinal axis oriented along the electric crystallographic axis X;
a fixed part fastened to one of the ends of the beam and a mass part fastened to the other end of the beam, the mass part being movable with an alternating displacement parallel to the plane XY of the monolithic structure following the second mode of vibration, and the mass part has a center of gravity located on a symmetry axis; and wherein the monolithic structure has the symmetry axis parallel to the electric crystallographic axis X, is movable with an alternating rotation about the symmetry axis following the first mode of vibration, and all the electrodes of the monolithic structure are located, at least in part, on the single substantially parallelepiped beam and shaped as two substantially identical strips extending parallel to the longitudinal axis of the beam.