EP2908188B1 - Adjustment of a clock piece resonator by changing the rigidity of a resilient return means - Google Patents

Description

Field of the invention

The invention relates to a method of frequency maintenance and regulation, around its natural frequency, of a clockwork resonator mechanism comprising at least one elastic return means which comprises at least one spiral or a torsion wire or a flexible guide, where at least one regulating device acting on said resonator mechanism is used with a periodic movement.

The invention also relates to a watch movement comprising at least one clock resonator mechanism designed to oscillate at a natural frequency, said resonator mechanism comprising at least one elastic return means comprising at least one spiral, said clock resonator mechanism comprising at least one sprung-balance assembly, a spiral of which constitutes a said elastic return means and is held between a stud at a first outer end and a ferrule at a second inner end.

The invention also relates to a timepiece, more particularly a watch, comprising at least one such watch movement.

The invention relates to the field of time bases in mechanical watchmaking, in particular based on a spiral balance resonator mechanism.

Background of the invention

The search for improved performance of watch time bases is a constant concern. An important limitation to the chronometric performance of mechanical watches is the use of conventional impulse exhausts, and no escape solution has ever been able to avoid this type of disturbance.

The document EP 1 843 227 A1 of the same applicant describes a coupled resonator comprising a first low frequency resonator for example of the order of a few hertz and a second resonator at higher frequency, for example of the order of one kilohertz. The invention is characterized in that the first resonator and the second resonator comprise permanent mechanical coupling means, said coupling making it possible to stabilize the frequency in the event of external disturbances, for example in the event of shocks.

The document CH 615 314 A3 in the name of PATEK PHILIPPE SA describes a mobile watch clock regulation unit, comprising an oscillating balance mechanically maintained by a spiral spring, and a vibrating member magnetically coupled with a fixed member for the synchronization of the balance. The balance and the vibrating member are constituted by a single mobile element vibrating and oscillating simultaneously. The vibration frequency of the vibrating member is an integer multiple of the oscillation frequency of the balance.

Summary of the invention

The invention proposes to manufacture a time base as accurate as possible.

To this end, the invention relates to a method for frequency maintenance and regulation of a clock resonator mechanism, around its natural frequency, according to claim 1.

The invention further relates to a watch movement according to claim 19.

The invention also relates to a timepiece, more particularly a watch, comprising at least one such watch movement.

Brief description of the drawings

• la figure 1 représente, de façon schématisée, un pendule dont on fait varier la longueur ;
• la figure 2 représente, de façon schématisée, un diapason avec deux balanciers-spiraux attachés l'un à l'autre
• la figure 3 représente, de façon schématisée, et partielle, le spiral d'un ensemble balancier-spiral, avec une spire additionnelle fixée à ce spiral et venant en doublure localement avec la courbe terminale externe du spiral, et un dispositif régulateur pour effectuer des torsions de sens opposés sur la courbe terminale externe et sur cette spire additionnelle ;
• la figure 4 représente, de façon similaire à la figure 3, une spire additionnelle et un dispositif régulateur actionnant une extrémité de cette spire additionnelle ;
• la figure 5 représente un spiral auquel est fixé un bras, et un dispositif régulateur actionnant une extrémité de ce bras ;
• la figure 6 illustre un spiral avec, au voisinage de sa courbe terminale externe, une autre spire qui est maintenue à une première extrémité par un appui manoeuvré par un dispositif régulateur, et qui est libre à une deuxième extrémité agencée pour venir périodiquement en contact avec la courbe terminale externe sous l'action du dispositif régulateur sur cet appui ;
• la figure 7 illustre un spiral comportant deux lames conductrices séparées par des éléments isolants, et les figures 7A et 7B montrent, en coupe, deux sections de ce spiral selon les champs électriques appliqués à ce spiral ;
• la figure 8 illustre un dispositif régulateur comportant un mobile rotatif équipé d'aimants à sa périphérie et dont le champ coopère périodiquement avec un aimant placé sur la courbe terminale externe d'un spiral ;
• la figure 9 illustre un mécanisme résonateur comportant un balancier comportant une virole maintenant un fil de torsion, dont un dispositif régulateur commande une variation périodique de la tension ;
• la figure 10 représente, sous forme d'un schéma-blocs, une montre comportant un mouvement mécanique avec un mécanisme résonateur régulé selon l'invention.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, in which:

• the figure 1 represents, schematically, a pendulum whose length is varied;
• the figure 2 schematically represents a tuning fork with two spiral pendulums attached to each other
• the figure 3 represents, schematically and partially, the hairspring of a balance-hairspring assembly, with an additional turn attached to this hairspring and coming locally lined with the external terminal curve of the hairspring, and a regulating device for making twists of direction opposite on the outer terminal curve and on this additional turn;
• the figure 4 represents, similarly to the figure 3 an additional turn and a regulating device actuating one end of this additional turn;
• the figure 5 represents a hairspring to which an arm is attached, and a regulating device actuating an end of this arm;
• the figure 6 illustrates a hairspring with, in the vicinity of its external terminal curve, another turn which is held at a first end by a support operated by a regulating device, and which is free at a second end arranged to periodically come into contact with the terminal curve external under the action of the regulator on this support;
• the figure 7 illustrates a spiral comprising two conductive blades separated by insulating elements, and the Figures 7A and 7B show, in section, two sections of this spiral according to the electric fields applied to this spiral;
• the figure 8 illustrates a regulating device comprising a rotating mobile equipped with magnets at its periphery and whose field cooperates periodically with a magnet placed on the outer terminal curve of a spiral;
• the figure 9 illustrates a resonator mechanism comprising a balance having a ferrule holding a torsion wire, a regulating device of which controls a periodic variation of the voltage;
• the figure 10 represents, in the form of a block diagram, a watch comprising a mechanical movement with a regulated resonator mechanism according to the invention.

Detailed Description of the Preferred Embodiments

The object of the invention is to manufacture a time base to make a mechanical timepiece, including a mechanical watch, as accurate as possible.

One way of doing this is to associate different resonators, either directly or via the exhaust.

To overcome the instability factor related to the escape mechanism, a parametric resonator system reduces the influence of the exhaust and thus make the watch more accurate.

According to the invention, a parametric oscillator uses, for the maintenance of oscillations, a parametric actuation which consists in varying one of the parameters of the oscillator with a regulation frequency ωR between 0.9 times and 1.1 times the value of a multiple integer of the eigenfrequency ω0 of the oscillator system to be regulated, this integer being greater than or equal to 2, and which is preferably an integer multiple, in particular double, of the natural frequency ω0.

By convention and in order to distinguish them well, here is called "regulator" 2 the oscillator which serves for maintenance and frequency regulation of the other system maintained, which is called "the resonator" 1.

où T est l'énergie cinétique et V l'énergie potentielle et l'inertie I(t), la rigidité k(t) et la position de repos x ₀(t) dudit résonateur sont une fonction périodique du temps. x est la coordonnée généralisée du résonateur.
L'équation du résonateur paramétrique forcé et amorti est obtenue par l'équation de Lagrange pour la lagrangienne L en ajoutant un forçant f(t) et une force de Langevin prenant en compte les mécanismes dissipatifs : $$\frac{{\partial }^{2}x}{{\partial }^{2}t}+\gamma \left(t\right)\frac{\partial x}{\partial t}+{\omega }^2\left(t\right)\left[x-x_0\left(t\right)\right]=f\left(t\right)$$

où le coefficient de la dérivée du premier ordre en x est : $$\gamma \left(t\right)=\left[\beta \left(t\right)+\dot{I}\left(t\right)\right]/I\left(t\right),$$

β(t) > 0 étant le terme décrivant les pertes, et où le coefficient du terme d'ordre nul dépend de la fréquence du résonateur $\omega \left(t\right)=\sqrt{k\left(t\right)/I\left(t\right)}.$

La fonction f(t) prend la valeur 0 dans le cas d'un oscillateur non-forcé.
Cette fonction f(t) peut, encore, être une fonction périodique, ou encore être représentative d'une impulsion de type Dirac.The Lagrangian L of a parametric resonator of dimension 1 is: $$\mathrm{The}=T-V=\frac{1}{2}I\left(t\right){\dot{x}}^2-\frac{1}{2}k\left(t\right){\left[x-x_0\left(\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}\right)\right]}^2$$

where T is the kinetic energy and V the potential energy and the inertia I ( t ), the stiffness k ( t ) and the rest position x ₀ ( t ) of said resonator are a periodic function of time. x is the generalized coordinate of the resonator.
The equation of the forced and damped parametric resonator is obtained by the Lagrange equation for the Lagrangian L by adding a forcing f (t) and a Langevin force taking into account the dissipative mechanisms: $$\frac{{\partial }^{2}x}{{\partial }^{2}t}+\gamma \left(t\right)\frac{\partial x}{\partial t}+{\omega }^2\left(t\right)\left[x-x_0\left(t\right)\right]=f\left(t\right)$$

where the coefficient of the first-order derivative in x is: $$\gamma \left(t\right)=\left[\beta \left(t\right)+\dot{I}\left(t\right)\right]/I\left(t\right),$$

β ( t )> 0 being the term describing the losses, and where the coefficient of the zero-order term depends on the frequency of the resonator $\omega \left(t\right)=\sqrt{k\left(t\right)/I\left(t\right)}.$

The function f (t) takes the value 0 in the case of a non-forced oscillator.
This function f (t) can, again, be a periodic function, or be representative of a Dirac type pulse.

The invention consists in varying, by the action of a maintenance oscillator or regulator, one or the other, or all, the terms β (t), ω (t), by modifying the real part and / or imaginary rigidity, with a regulation frequency ωR which is between 0.9 times and 1.1 times the value of an integer multiple, this integer being greater than or equal to 2, in particular double, of the natural frequency ω0 of the system oscillator to be regulated.

In a particular embodiment, the regulation frequency ωR is an integer multiple, in particular double, of the natural frequency ω0 of the resonator system to be regulated.

In one variant, the rest position x ₀ (t) varies simultaneously with the parameters β (t), ω (t), with a regulation frequency ωR which is between 0.9 times and 1.1 times the value of an integer multiple, this integer being greater than or equal to 2, in particular double, of the natural frequency ω 0 of the oscillator system to be regulated.

Preferably, all the terms β (t), ω (t), x ₀ (t), vary with a control frequency wR which is preferably a multiple integer, in particular double, of the natural frequency ω0 of the resonator system to be regulated.

Generally, the maintenance oscillator or regulator, in addition to the modulation of the parametric terms, also introduces a nonparametric maintenance term f (t), the amplitude of which is negligible once the parametric regime is reached [ WB Case, The pumping of a swing from the standing position, Am. J. Phys. 64, 215 (1996) )].
Alternatively, the forcing term f (t) may be introduced by a second maintenance mechanism.

avec L la longueur du pendule, et g l'attraction de la pesanteur.The parameters of this equation are the frequency term ω and the term of losses and friction β. The quality factor of the oscillator is defined by Q = ω / β.
To better understand the phenomenon, we can approach the example of a pendulum whose length is varied. In that case, $${\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^2=\frac{\mathrm{boy\; Wut}}{\mathrm{The}}$$

with L the length of the pendulum, and g the attraction of gravity.

In this particular example, if the length L is modulated in time periodically with a frequency 2ω and a modulation amplitude δL sufficient (δL / L> 2β / ω), the system oscillates at the frequency ω without amortizing.
[ D. Rugar and P. Grutter, Mechanical parametric amplification and thermomechanical noise squeezing, PRL 67, 699 (1991) ) AH Nayfeh and DT Mook, Nonlinear Oscillations, Wiley-Interscience, (1977) )].

The principle can be reproduced in a timepiece or a watch which comprises a mechanical resonator balance sprung, with one end of the spiral attached to a ferrule integral with the balance, and the other end attached to a stud.

The parametric maintenance of such a balance spring-balance system can in particular be achieved by making this stud mobile, periodically.

The oscillation can be maintained and the accuracy of the system is notoriously improved.

The choice of a frequency of an excitation oscillator at twice the frequency of the system which one wants to stabilize in regularity of oscillation makes it possible to carry out the modulation on a complete alternation, and to obtain a null damping or negative.

The industrialization of such parametric oscillator systems is related to two essential functions: energy supply and metering.

These two functions can be separated, as illustrated by the figure 2 , using a tuning fork with two spiral pendants attached to each other, where one oscillating at a frequency 2ω is linked to the escapement, and the other oscillating at a frequency w is linked to the count.

It is still possible to favor a modification of the losses by friction in the air, rather than to oscillate the term of frequency, or to modify the inertia of the balance by an imbalance.

For maximum efficiency, the maintenance is advantageously carried out with an integer multiple frequency, in particular double, of the frequency of the maintained resonator. The mechanical means of maintenance can take different forms.

The present invention consists in varying the rigidity of the spiral.

The excitation at twice the frequency can be performed with a square signal, or with a pulse signal, it is not essential to have a sinusoidal excitation.

The maintenance regulator does not need to be very precise: its possible lack of precision only results in a loss of amplitude, but without variation of the frequency (except of course if this frequency is very variable, which is to be avoided). In fact, these two oscillators, maintenance regulator and resonator maintained, are not coupled, but one maintains the other, one-way.

In a preferred embodiment, there is no coupling spring between these two oscillators.

It is well understood that the invention differs from the coupled oscillators known elsewhere: indeed, it is not desired, in the implementation of the invention, reversibility of energy transfer between two oscillators, but rather, in the whenever possible, a one-way energy transfer from one oscillator to the other.

The invention more particularly relates to the frequency regulation of a clock resonator by acting on the rigidity of an elastic return means.

Thus, the invention relates to a method of frequency regulation of a clock resonator mechanism 1 around its natural frequency ω0. This method implements at least one regulating device 2 imparting a periodic movement to at least one component of the resonator mechanism 1 or to a tooling influencing the position or the rigidity of such a component of the resonator mechanism 1.

And this periodic movement imposes a periodic modulation at least of the resonant frequency of the resonator mechanism 1, acting at least on the rigidity of a return means that includes this resonator mechanism 1, with a regulation frequency ωR which is between 0.9 times and 1.1 times the value of an integer multiple of the natural frequency ω0, this integer being greater than or equal to 2.

In a particular embodiment of the invention, the periodic movement imposes a periodic modulation of the resonant frequency of the resonator mechanism 1, imposing both a modulation of the rigidity of the resonator mechanism 1 and an inertial modulation of the mechanism resonator 1.

In a particular implementation of the invention, the periodic movement imposes a periodic modulation of the resonant frequency of the resonator mechanism 1, by imposing a modulation of the section of a spring, which comprises said resonator mechanism 1 and / or a modulating the modulus of elasticity of a biasing means that comprises the resonator mechanism 1, and / or modulating the shape of a biasing means that comprises the resonator mechanism 1.

In a particular application, this periodic movement can, again, impose a periodic modulation of the resonance frequency of the resonator mechanism 1, by imposing, again, a modulation of the active length of a spring, which this resonator mechanism 1 comprises.

In a particular implementation of the invention, the periodic movement imposes a periodic modulation of the resonance frequency of the resonator mechanism 1 by imposing both a modulation of the rigidity of the resonator mechanism 1, and a modulation of the rest point of the resonator mechanism 1.

In a particular application illustrated by the figures, at least one said regulating device 2 is printed, printing a periodic movement to least one component of the resonator mechanism 1, or to a tooling influencing the position of such a component of the resonator mechanism 1, and this periodic movement is printed to a resonator mechanism 1 comprising at least one elastic return means 40 comprising at least one spiral 4, or, in a variant close to the invention a torsion wire (or a flexible guide) 46, and is made to act at least one said regulating device 2 by controlling a periodic variation of the rigidity of the elastic return means 40 by modulating its section and / or modulus of elasticity and / or shape and / or stresses at its attachment points.

According to the invention, this method is applied to a resonator mechanism 1 comprising at least one elastic return means 40 comprising at least one hairspring 4, and at least one such a regulating device 2 is actuated by controlling a periodic variation of the real part and / or the imaginary part of the rigidity of this elastic return means 40, the real part of the stiffness defining the frequency of this resonator mechanism 1, and the imaginary part of the rigidity defining the quality factor of this resonator mechanism 1 .

In the variants illustrated in Figures 3 to 8 (Where the balance is not shown so as not to encumber the figures), this method is applied to a sprung-balance assembly 3, the spiral 4 of which constitutes the elastic return means 40 and is held between a stud 5 at a first external end 6 and a ferrule 7 at a second inner end 8, and is made to act at least one such regulator device 2 by controlling a periodic variation of the real part and / or the imaginary part of the rigidity of the spiral 4.

In the variant of the figure 3 the external terminal curve 17 of the hairspring 4 is doubled locally by an additional turn 18 fixed to this hairspring 4 at at least a first junction point 19, and is made periodically with the regulating device 2 of twists in opposite directions on the outer end curve 17 and on the additional turn 18, by acting on the peak 5 for the outer terminal curve 17, and on an end 18A opposite this first junction point 19 of the additional turn 18 for the additional turn 18. This double torsion has the advantage of allowing the modification of the rigidity of the spiral, without modifying its position in its plane.

In the variant of the figure 4 , the outer terminal curve 17 of the spiral 4 is locally doubled by an additional turn 18 fixed to this spring 4 at at least a first junction point 19, and is carried out periodically with the device regulator 2 a movement on an end 18A opposite this first junction point 19 of the additional coil 18. The stiffness of the external terminal curve, and consequently that of the spiral, is thus modified. It is also possible to use the regulator device 2 to move the stud 5 and the end 18A.

• ou bien on choisit une telle spire additionnelle 18 de souplesse équivalente à celle de la courbe terminale externe 17,
• ou bien on choisit une telle spire additionnelle 18 plus rigide que la courbe terminale externe 17.

We can choose to give a particular rigidity to this additional turn 18:

• or one chooses such additional turn 18 of flexibility equivalent to that of the external terminal curve 17,
• or we choose such additional turn 18 more rigid than the outer terminal curve 17.

In the variant of the figure 5 , an arm 20 is attached to the external terminal curve 17 of the hairspring 4 at at least a second junction point 21, and a movement is made periodically with the regulating device 2 on one end 22 of the arm 20 opposite this second point. In a particular variant, the arm 20 is chosen to be stiffer than the external terminal curve 17.

In the variant of the figure 6 positioned near the outer end curve 17 of the hairspring 4 is another turn 23, which is held at a first end by a support 24 operated by the regulating device 2, and which is free at a second end 25 arranged to periodically come into contact with the external terminal curve 17 under the action of the regulating device 2 on this support 24. This other curved turn 23 thus comes closer, and possibly stick, periodically to the spring 4 to modify the stiffness of the return component .

In the variant of the figure 7 the spiral 4 is made with at least two conductive strips 41, 42, separated by insulating elements 43 and such a regulating device 2 is used to periodically apply a field to the two blades 41, 42 so as to modify the gap E1 ( Figure 7A ) or E2 ( Figure 7B ) between these two blades 41,42, and thus to change the total section and stiffness of the spiral 4. In a variant, they are periodically applied a different field.

In particular, the two blades 41, 42 are subjected to a different electromagnetic and / or electrostatic and / or magnetostatic field by a movement printed on a ferromagnetic or magnetized or electrostatically conductive or electrised polar mass (in particular magnets or electrets) in the vicinity. each blade so as to give rise to an electric or magnetic or electrostatic or magnetostatic force between them, and to approach them or to move them away from each other. The rigidity of the spiral 4 is modified because its section varies. The movement is preferably mechanically printed to these polar masses.

In a variant, the two blades 41, 42 are subjected to an electric or electrostatic field so as to locally polarize the spiral 4 and locally modify its rigidity 4.

In the variant of the figure 8 , such a regulating device 2 is used comprising a rotating mobile 28 equipped with magnets 29 at its periphery and whose field cooperates periodically with at least one magnet 45 placed on the spiral 4 (one can imagine placing the magnet on the side of the ferrule), to periodically change the stiffness of the hairspring 4. The prestressing of the hairspring and the radial position of the counting point are also periodically modified.

In another variant, a rotating mobile 28 is used that is inhomogeneously magnetized to periodically modify the rigidity of the spring 4 by the phenomenon of magnetostriction.

In an electrostatic variant, use is made of such a regulator device 2 comprising a similar rotating mobile 28, this time equipped with electrets at its periphery, and whose electric field cooperates periodically with at least one electret placed on the external terminal curve 17 of the spiral 4, to periodically change the rigidity of the spiral 4, by the phenomenon of piezoelectricity.

In yet another variant, the rigidity is modulated through a temperature variation.

In an advantageous implementation of this method, valid for all the variants exposed above, the regulation frequency ωR is twice the natural frequency ω0.

In an advantageous implementation of the method, the relative amplitude of the modulation of the real part of the rigidity of the resonator mechanism 1 is greater than twice the inverse of the quality factor of the resonator mechanism 1.

The invention also relates to a watch movement 10, comprising at least one clocking resonator mechanism 1 designed to oscillate at a natural frequency ω 0, this clock resonator mechanism 1 comprising at least one elastic return means 40 comprising at least a spiral 4, or in a variant close to the invention a torsion wire 46 or a flexible guide. According to the invention this movement 10 comprises at least one regulating device 2 controlling a periodic variation of the rigidity of the elastic return means 40 with a control frequency ωR, which is between 0.9 times and 1.1 times the value of an integer multiple of the natural frequency ω0 of the resonator 1, said integer being greater than or equal to 2.

In the variants illustrated in Figures 3 to 8 , the clockwork resonator mechanism 1 comprises at least one balance spring-balance 3, the spiral 4 constitutes the elastic return means 40 and is held between a stud 5 at a first outer end 6 and a ferrule 7 to a second internal end 8, and the regulator device 2 controls a periodic variation of the rigidity of the spiral 4.

In the variant of the figure 3 , the movement 10 comprises an additional turn 18 fixed to this spring 4 in at least a first junction point 19 and lining locally with the external terminal curve 17 of the spiral 4. And the regulating device 2 periodically makes twists of opposite directions on the outer terminal curve 17 and on the additional turn 18, by acting on the stud 5 for the outer terminal curve 17, and on one end 18A of the additional turn 18 opposite this first connection point 19.

In the variant of the figure 4 , the movement 10 comprises an additional turn 18 fixed to this spring 4 at at least a first junction point 19 and lining locally with the external terminal curve 17 of the spring 4, and the regulating device 2 periodically moves on an end 18A of the additional turn 18 opposite this first junction point 19.

The additional turn 18 is either of flexibility equivalent to that of the external terminal curve 17, or much more rigid than the external terminal curve 17.

In the variant of the figure 5 , the movement 10 comprises an arm 20 fixed to the outer end curve 17 of the hairspring 4 at at least a second junction point 21, and the regulating device 2 periodically moves on one end 22 of the arm 20 opposite to this second junction point 21.

In a particular embodiment, the arm 20 is more rigid than the external terminal curve 17.

In the variant of the figure 6 , the movement 10 comprises, in the vicinity of the outer terminal curve 17 of the spiral 4, another turn 23 which is held at a first end by a support 24 operated by the regulating device 2, and which is free at a second end 25 arranged to come periodically in contact with the external terminal curve 17 under the action of the regulating device 2 on this support 24.

In the variant of the figure 7 , the hairspring 4 comprises at least two conductive strips 41, 42, separated by insulating elements 43, and the regulating device 2 is arranged to periodically subject the two blades 41, 42 to an electric and / or magnetic field (in the broad sense , according to the definition of fields above), so as to change the gap E1, E2, between the two blades 41, 42, and thus to modify the total section and the rigidity of the spiral 4. In particular, the regulator 2 is arranged to periodically subject the two blades 41, 42 to a different electric field.

In the variant of the figure 8 , the regulating device 2 comprises a rotating mobile 28 equipped with magnets 29 at its periphery and whose magnetic field cooperates periodically with at least one magnet 45 placed on the external terminal curve 17 of the spiral 4, to periodically modify the rigidity of the spiral 4 .

In the variant of the figure 9 , the resonator mechanism 1 comprises at least one rocker 26 comprising a ferrule 7 holding a torsion wire 46 which constitutes the elastic return means 40, and the regulating device 2 controls a periodic variation of the tension of the torsion wire 46.

In yet another variant, layers or electrostatic elements may be implemented to vary the rigidity of a spring or spiral by covering it partially or completely with a piezoelectric layer activated by a small electronic module.

Preferably, the regulation frequency wR of the regulator device 2 is twice the natural frequency ω0 of the resonator mechanism 1.

The invention also relates to a timepiece, more particularly a watch, comprising at least one such watch movement 10.

Claims (26)

1. Method of maintaining and regulating the frequency of a timepiece resonator mechanism (1) about its natural frequency (ω0), the mechanism including at least one elastic return means (40) that includes at least one balance spring (4), wherein there is implemented at least one regulator device (2) acting on said resonator mechanism (1) with a periodic motion, said periodic motion imposing a periodic modulation of the resonant frequency of said resonator mechanism (1), with a regulation frequency (ωR) that is comprised between 0.9 times and 1.1 times the value of an integer multiple of said natural frequency (ω0), said integer being greater than or equal to 2, said at least one regulator device (2) imparting a periodic motion to at least one component of said resonator mechanism (1) or to a tool affecting the position of a component of said resonator mechanism (1), wherein said regulator device (2) is made to act on said at least one balance spring (4) which forms an elastic return means (40) and is held between a balance spring stud (5) at a first outer end (6) and on a collet (7) at a second inner end (8), said regulator device (2) being capable of controlling a periodic variation in the stiffness of said balance spring (4) by modulating its cross-section and/or its modulus of elasticity and/or its shape and/or the stresses at its point of attachment, characterized in that said periodic motion imposes a periodic modulation of the resonant frequency of said resonator mechanism (1), by imposing a modulation of the cross-section of said at least one balance spring (4).
2. Method according to claim 1, characterized in that the outer terminal curve (17) of said balance spring (4) is locally lined with an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19), and in that twists are periodically created with said regulator device (2) in opposite directions on said outer terminal curve (17) and on said additional coil (18), by acting on said balance spring stud (5), for said outer terminal curve (17), and on an end (18A) opposite to said first attachment point (19) of said additional coil (18) for said additional coil (18).
3. Method according to claim 2, characterized in that said additional coil (18) is chosen to have equivalent flexibility to that of said outer terminal curve (17).
4. Method according to claim 2, characterized in that said additional coil (18) is chosen to be stiffer than said outer terminal curve (17).
5. Method according to claim 1, characterized in that the outer terminal curve (17) of said balance spring (4) is locally lined with an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19), and in that a motion is periodically made with said regulator device (2) on an end (18A) opposite to said first attachment point (19) of said additional coil (18).
6. Method according to claim 5, characterized in that said additional coil (18) is chosen to have equivalent flexibility to that of said outer terminal curve (17).
7. Method according to claim 5 or 6, characterized in that said additional coil (18) is chosen to be stiffer than said outer terminal curve (17).
8. Method according to claim 1, characterized in that an arm (20) is attached to the outer terminal curve (17) of said balance spring (4) at at least a second attachment point (21), and in that a motion is periodically made with said regulator device (2) on an end (22) of said arm (20) opposite to said second attachment point (21).
9. Method according to claim 8, characterized in that said arm (20) is chosen to be stiffer than said outer terminal curve (17).
10. Method according to claim 1, characterized in that, in proximity to the outer terminal curve (17) of said balance spring (4), there is positioned another coil (23) held at a first end by a support (24) operated by said regulator device (2), and free at a second end (25) arranged to periodically come into contact with said outer terminal curve (17) under the action of said regulator device (2) on said support (24).
11. Method according to claim 1, characterized in that said balance spring (4) is made with at least two conductive strips (41; 42) separated by insulating elements (43) and in that a said regulator device (2) is used to periodically apply an electrical and/or magnetic field to said two strips (41; 42) so as to modify the distance (E1; E2) between the two said strips (41; 42) and thereby modify the total cross-section and the stiffness of said balance spring (4).
12. Method according to claim 1, characterized in that said balance spring (4) is made with at least two conductive strips (41; 42) separated by insulating elements (43) and in that a said regulator device (2) is used to periodically subject said two strips (41; 42) to a different electrical or electrostatic field in order to locally polariser said balance spring (4) and locally modify its stiffness.
13. Method according to claim 1, characterized in that there is used a said regulator device (2) comprising a rotating wheel set (28) provided with magnets (29) at its periphery and whose field periodically cooperates with at least one magnet (45) placed on the outer terminal curve (17) of said balance spring (4), to periodically modify the stiffness of said balance spring (4).
14. Method according to claim 1, characterized in that there is used a said regulator device (2) comprising a rotating wheel set (28) provided with electrets at its periphery and whose electrical field periodically cooperates with at least one electret placed on the outer terminal curve (17) of said balance spring (4), to periodically modify the stiffness of said balance spring (4).
15. Method according to claim 1, characterized in that there is used a said regulator device (2) comprising an inhomogeneously magnetized rotating wheel set (28) to periodically modify the stiffness of said balance spring (4) by the phenomenon of magnetostriction.
16. Method according to any of claims 1 to 15, characterized in that said periodic motion imposes a periodic modulation of the resonant frequency of said resonator mechanism (1) by imposing both a modulation of the stiffness of said resonator mechanism (1) and a modulation of the position of the rest point of said resonator mechanism (1).
17. Method according to any of claims 1 to 16, characterized in that said regulation frequency (ωR) is double said natural frequency (ω0).
18. Method according to any of claims 1 to 17, characterized in that the relative amplitude of modulation of the real part of the stiffness of said resonator mechanism (1) is more than two times the inverse quality factor of said resonator mechanism (1).
19. Timepiece movement (10) including at least one timepiece resonator mechanism (1) devised to oscillate at a natural frequency (ω0), said timepiece resonator mechanism (1) including at least one elastic return means (40) comprising at least one balance spring (4), said timepiece resonator mechanism (1) comprising at least one sprung balance assembly (3), whose balance spring (4) forms a said elastic return means (40) and is held between a balance spring stud (5) at a first outer end (6) and on a collet (7) at a second inner end (8), said movement (10) comprising at least one regulator device (2) arranged to control a periodic variation in the stiffness of said at least one balance spring (4) with a regulation frequency (ωR) that is comprised between 0.9 times and 1.1 times the value of an integer multiple of said natural frequency (ω0) of said resonator (1), said integer being greater than or equal to 2,
    said regulator device (2) being arranged to impart a periodic motion to at least one component of said resonator mechanism (1) or to a tool affecting the position of a said component of said resonator mechanism (1), said regulator device (2) being arranged to control a periodic variation in the stiffness of said at least one balance spring (4) by modulating its cross-section and/or its modulus of elasticity and/or its shape and/or the stresses at its point of attachment, characterized in that said resonator mechanism (1) includes:

    - either an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19) and locally lining the outer terminal curve (17) of said at least one balance spring (4), and said regulator device (2) being arranged to periodically create twists in opposite directions on said outer terminal curve (17) and on said additional coil (18), by acting on said balance spring stud (5) for said outer terminal curve (17), and on one end (18A) of said additional coil (18) opposite to said first attachment point (19);

    - or an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19) and locally lining the outer terminal curve (17) of said at least one balance spring (4), and said regulator device (2) being arranged to periodically make a motion on one end (18A) of said additional coil (18) opposite to said first attachment point (19);

    - or an arm (20) attached to the outer terminal curve (17) of said at least one balance spring (4) at at least a second attachment point (21), and said regulator device (2) being arranged to periodically make a motion on one end (22) of said arm (20) opposite to said second attachment point (21);

    - or, in proximity to the outer terminal curve (17) of said at least one balance spring (4), another coil (23) which is held at a first end by a support (24) arranged to be operated by said regulator device (2), and which is free at a second end (25) arranged to periodically come into contact with said outer terminal curve (17) under the action of said regulator device (2) on said support (24);

    - or a balance spring (4) that comprises at least two conductive strips (41; 42) separated by insulating elements (43), and said regulator device (2) being arranged to periodically apply an electrical and/or magnetic field to said strips (41; 42) so as to modify the distance (E1; E2) between the two said strips (41; 42) and thereby modify the total cross-section and the stiffness of said at least one balance spring (4);

    - or a said regulator device (2) that comprises a rotating wheel set (28) provided with magnets (29) at its periphery and whose field is arranged to periodically cooperate with at least one magnet (45) placed on the outer terminal curve (17) of said at least one balance spring (4), to periodically modify the stiffness of said at least one balance spring (4).
20. Movement (10) according to claim 19, characterized in that said resonator mechanism (1) comprises an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19) and locally lining the outer terminal curve (17) of said at least one balance spring (4), and said regulator device (2) being arranged to periodically create twists in opposite directions on said outer terminal curve (17) and on said additional coil (18), by acting on said balance spring stud (5) for said outer terminal curve (17), and on one end (18A) of said additional coil (18) opposite to said first attachment point (19), and in that said additional coil (18) is of equivalent flexibility to said outer terminal coil (17).
21. Movement (10) according to claim 19, characterized in that said resonator mechanism (1) comprises an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19) and locally lining the outer terminal curve (17) of said at least one balance spring (4), and said regulator device (2) being arranged to periodically create twists in opposite directions on said outer terminal curve (17) and on said additional coil (18), by acting on said balance spring stud (5) for said outer terminal curve (17), and on one end (18A) of said additional coil (18) opposite to said first attachment point (19), and in that said additional coil (18) is stiffer than said outer terminal coil (17).
22. Movement (10) according to claim 19, characterized in that said resonator mechanism (1) comprises an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19) and locally lining the outer terminal curve (17) of said at least one balance spring (4), said regulator device (2) being arranged to periodically make a motion on one end (18A) of said additional coil (18) opposite to said first attachment point (19), and in that said additional coil (18) is of equivalent flexibility to said outer terminal coil (17).
23. Movement (10) according to claim 19, characterized in that said resonator mechanism (1) comprises an additional coil (18) attached to said balance spring (4) at at least a first attachment point (19) and locally lining the outer terminal curve (17) of said at least one balance spring (4), said regulator device (2) being arranged to periodically make a motion on said additional coil (18) opposite to said first attachment point (19), and in that said additional coil (18) is of greater stiffness than said outer terminal coil (17).
24. Movement (10) according to claim 19, characterized in that said resonator mechanism (1) comprises an arm (20) attached to the outer terminal curve (17) of said at least one balance spring (4) at at least a second attachment point (21), said regulator device (2) being arranged to periodically make a motion on one end (22) of said arm (20) opposite to said second attachment point (21), and in that said arm (20) is stiffer than said outer terminal curve (17).
25. Movement (10) according to any of claims 19 to 24, characterized in that said regulation frequency (ωR) of said regulator device (2) is double said natural frequency (ω0) of said resonator mechanism (1).
26. Timepiece (30) including at least one timepiece movement (10) according to claim 25, characterized in that the timepiece is a watch.

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