Office National D'etudes Et De Recherches Aerospatiales

Onera (office National D'etudes Et De Recherches Aerospatiales)

Onera

Marc Pernice

Denis Janiaud

Olivier Le Traon

Claude Chartier

Raphaël Levy

Jean Guerard

Serge Muller

Vincent Gaudineau

Bernard Lecorre

Rachid Taibi

Stève Masson

Marc Dupont

Elisabeth Roy

Mechanical resonators for making timepieces have the drawback of not being simultaneously efficient, compact, and inexpensive. The invention is a planar structure of a mechanical resonator () that is suitable for reducing bulkiness and manufacturing cost and comprises a bar (R) vibrating in longitudinal expansion/compression resonance and two beams, () each vibrating simultaneously in longitudinal expansion/compression and it bending oscillation in the plane of the structure and connected to the bar by a connection element () on the median plane (&#x3c0;) of the bar, thereby enabling the effects of the transverse deformations of the bar, due to the Poisson ratio of the material, to not be transmitted to the attachment pads (PF) of the resonator. Thus, the quality factor of the resonator can be very high.

Planar structure of a mechanical resonator decoupled by bending oscillation and expansion/compression vibrations

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.

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

A sensor comprises two identical vibrating members operating with a common working frequency and joined to each other by a mechanical decoupling device. The device comprises a frame and two connecting bridges each supporting one member. The frame comprises a succession of mass portions and thinned portions so that the frequency of one mode of structural resonance of the frame is substantially equal to the common working frequency, and each connecting bridge is disposed in a node of vibration of the frame at the common working frequency. Thus, the vibrations of the two vibrating members are decoupled from each other.

Mechanical decoupling device for monolithic differential vibrating sensor

The invention concerns an installation with piezoelectric element for transmitting or receiving ultrasonic waves in a structure, the electrodes () of said element () being connected, as the case may be, to a powering circuit producing energizing electric signals designed to enable it to transmit ultrasonic signals in said structure (), or to a circuit receiving electric signals transmitted by said element under an energizing ultrasound received by it from said structure, said piezoelectric element () being integrated in the structure. The powering or receiving circuits of said piezoelectric elements () consist each of a magnetic induction loop () likewise comprised in the structure () and capable of receiving from an external circuit () or respectively transmitting thereto, electromagnetic signals.

Installation with piezoelectric element for equipping a structure and piezoelectric element for same

Growing community of inventors

Fresnes, France

Marc Pernice