The Swatch Group Research and Development Ltd

Alexandre Didier

Matthias Imboden

Alexandre Haemmerli

Jean-Jacques Born

Yvan Ferri

Lionel Paratte

Cédric Nicolas

François Gueissaz

Mohammad Hussein Kahrobaiyan

Elias Laforge

Léonard Testori

A rotary piezoelectric motor (), in particular for a timepiece, including a rotor () configured to rotate and actuate a mechanical device, and a stator () configured to rotate the rotor (), the stator () including a piezoelectric actuator provided with a resonator () arranged to perform an oscillatory motion, and a fixed element (). The resonator in a movable element () arranged at a distance from the fixed element () and connected to the fixed element (), the piezoelectric actuator being configured to move the movable element () against the rotor () to make it rotate, the movement of the movable element () making the rotor () rotate in a first direction.

Rotary piezoelectric motor, in particular for watchmaking

A piezoelectric balance spring () for a circuit () for self-regulating an oscillation frequency of an oscillating mechanical system (), or an energy recovery circuit or a motor circuit for actuating the movement or for the automatic maintenance thereof. The piezoelectric balance spring () includes at least one piezoelectric layer (') provided on a top face () or bottom face of a certain number of coils of the spring in a plane, and at least two pairs of electrodes (), whereby the electrodes of each pair are provided on two opposing faces of the same piezoelectric layer or respectively two piezoelectric layers so as to apply a reverse bias voltage on each pair of electrodes.

Piezoelectric balance spring, and method for manufacturing the balance spring

A horological movement includes an analogue time display, a gear train, a barrel driving the analogue display via the gear train, and an oscillator formed of a resonator, including a balance and a piezoelectric spring, and a mechanical escapement coupling the balance to the gear train. This horological movement further includes an electric energy source which is associated with the electronic control circuit, which is arranged to be able to control the application of an electrical supply voltage to the piezoelectric spring to excite the oscillator to obtain a functional oscillation of the resonator and then to maintain this functional oscillation. The mechanical escapement is an escapement for counting the alternations of the functional oscillation, to pace the running of the horological movement, without the resonator being able to receive from the barrel via this mechanical escapement enough mechanical energy to maintain the functional oscillation.

Horological movement provided with an oscillator comprising a piezoelectric spring

An horological movement includes an analogue time display, a geartrain, a barrel and an electromechanical oscillator, which is formed of a resonator, including a balance and a piezoelectric balance-spring, and a mechanical escapement, and further includes an electronic control circuit connected to an electrical energy source and arranged to be able to control the application of an electrical voltage on at least one electrode of the piezoelectric balance-spring so as to generate driving electrical pulses for the oscillator. The horological movement is configured such that the barrel is capable, in a first main state, of maintaining alone a functional oscillation of the oscillator with a first amplitude, while in a second main state, the electronic control circuit powers the piezoelectric balance-spring to maintain, partially or fully, the oscillation of the resonator with a second amplitude greater than the first amplitude for any spatial orientation, the second amplitude being preferably constant.

Horological movement equipped with an oscillator comprising a piezoelectric balance-spring

Growing community of inventors

Erlach, Switzerland

Alexandre Didier