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.

A mechanical oscillator endowed with a strip, with the aforesaid strip incorporating a first silicon layer having a crystal lattice extending along a first direction of one plane, a thermal compensation layer composed of a material having a Young's modulus thermal coefficient of opposite sign to that of the silicon, and a second silicon layer having a crystal lattice extending in a second direction of the plane, with the first and direction being offset at an angle of 45° within the plane of the layers, and with the thermal compensation layer extending between the first and second silicon layers.

A method for manufacturing a plurality of mechanical resonators (100) in a manufacturing wafer (10), the resonators being intended to be fitted to an adjusting member of a timepiece, the method comprising the following steps: (a) manufacturing a plurality of resonators in at least one reference wafer according to reference specifications, such manufacture comprising at least one lithography step to form patterns of the resonators on or above the reference wafer and a step of machining in the reference plate using the patterns; (b) for the at least one reference plate, establishing a map indicative of the dispersion of stiffnesses of the resonators relative to an average stiffness value; (c) dividing the map into fields and determining a correction to be made to the dimensions of the resonators for at least one of the fields in order to reduce the dispersion; (d) modifying the reference specifications for the lithography step so as to make the corrections to the dimensions for the at least one field in the lithography step; (e) manufacturing resonators in a manufacturing wafer using the modified specifications.

The method for manufacturing timepiece hairsprings according to the invention comprises the following successive steps: a) forming hairsprings in a wafer, b) forming a thermal compensation layer on the hairsprings, c) identifying the hairsprings having a stiffness within a predetermined range, d) optionally, detaching from the wafer the hairsprings identified in step c), e) modifying the other hairsprings so that the stiffness of at least some of them is within the predetermined range, f) detaching from the wafer these other hairsprings and, if they have not been detached in step d), the hairsprings identified in step c). This method makes it possible to reduce manufacturing dispersions between the hairsprings.

A method for manufacturing a balance spring intended to equip a balance of a horological movement, including a step of producing a blank made of a niobium and hafnium alloy including between 5 and 60 wt %, preferably between 5 and 30 wt %, and more preferably between 8 and 12 wt % hafnium, a step of annealing and cooling the blank, at least one step of deforming the annealed blank in order to form a wire. The method includes, before the deformation step, a step of depositing, on the blank, a layer of a ductile material chosen from the group consisting of copper, nickel, cupronickel, cupro-manganese, gold, silver, nickel-phosphorus Ni—P and nickel-boron Ni—B, in order to facilitate the wire shaping operation. A balance spring can be produced by the manufacturing method.

A method for manufacturing a spiral spring may include: (a) providing a blank with an Nb—Ti core; (b) beta-quenching the blank; (c) deforming the blank in several sequences; (d) winding to form the spiral spring; (e) final heat treatment on the spiral spring. The blank in (a) may include a layer of X including Cu, Sn, Fe, Pt, Pd, Rh, Al, Au, Ni, Ag, Co and Cr or an alloy of one of these elements around the Nb—Ti core. The method may include heat treating to partially transform the layer of X into a layer of X, Ti intermetals around the Nb—Ti core, and may be carried out between (b) and (c) or between two sequences of (c). The method may include removing the part of the layer of X, which may be carried out between (b) and (c), between two sequences of (c) or between (c) and (d).

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 so as to excite the oscillator to obtain a functional oscillation of the resonator and then to maintain this functional oscillation. The mechanical escapement is configured so as to be an escapement for counting the alternations of the functional oscillation, so as 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.

The present invention relates to a spiral spring for a balance wheel made of an alloy of niobium and titanium with an essentially single-phase structure, and the method of manufacture thereof which comprises: a step of producing a blank in a niobium-based alloy consisting of: niobium: balance to 100 wt %, titanium: between 40 and 49 wt %, traces of elements selected from the group consisting of O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, between 0 and 1600 ppm by weight individually, and cumulatively less than 0.3 wt %, a step of type β hardening of said blank at a given diameter, in such a way that the titanium of the niobium-based alloy is essentially in the form of a solid solution with niobium in β phase, the content of titanium in α phase being less than or equal to 10 vol %, at least one deformation step of said alloy alternating with at least one step of heat treatment, the number of steps of heat treatment and of deformation being limited so that the niobium-based alloy obtained retains a structure in which the titanium of the niobium-based alloy is essentially in the form of a solid solution with niobium in β phase, the content of titanium in α phase being less than or equal to 10 vol % and it has an elastic limit greater than or equal to 600 MPa and an elastic modulus less than or equal to 100 GPa, a step of winding to form the spiral spring being carried out before the last heat treatment step.

A component intended to be in friction contact with another component, the component being coated with an electrically conductive layer in one piece, at least partially covering every surface of the component, the friction occurring on at least one of these surfaces, called the functional surface, the functional surface being surrounded by a plurality of side surfaces, the component having on its functional surface a texture formed of a succession of troughs coated with the electrically conductive layer, the troughs each extending between two side surfaces such that the electrically conductive layer remains in one piece over the component despite the wear caused by friction on the functional surface. The invention also relates to the method for manufacturing the component by the DRIE (deep reactive ion etching) process, wherein surface defects on the sides machined by the DRIE process are used to form the troughs.

A balance spring intended to equip a balance of a horological movement, wherein the balance spring is made of an alloy consisting of Nb, Ti, H and possible traces of other elements selected from O, C, Fe, N, Ni, Si, Cu and Al, with the following weight percentages: a Ti content comprised between 1 and 80 wt %, a H content comprised between 0.17 and 2 wt %, a total content of all other elements of less than or equal to 0.3 wt %, the remainder to 100 wt % consisting of Nb. A manufacturing method for the balance spring is also disclosed and includes a step of thermochemically treating a blank made of a Nb and Ti alloy in an atmosphere including hydrogen so as to enrich the Nb and Ti alloy with hydrogen in interstitial form.