CH714483A2 - Timepiece comprising a mechanical oscillator associated with a control system. - Google Patents

Abstract

The invention relates to a timepiece comprising a mechanical oscillator that clock the march of a watch movement. To regulate this step, the timepiece further comprises an electromechanical transducer formed by an electromagnetic assembly comprising at least one coil (28) and at least one magnet mounted on the balance of the mechanical oscillator. The induced voltage signal produced by the electromagnetic transducer during each oscillation, has, in a first half-wave before the oscillator passes through its neutral position, a first lobe of maximum amplitude having a first polarity and, in a second half-wave following a passage through the neutral position, a second lobe of maximum amplitude having a second polarity opposite to the first. The timepiece further comprises an electrical converter (56) comprising two supply capacitors (C1, C2) and a regulating device (52) for the average frequency of the mechanical oscillator. The first power supply is only charged with a positive voltage while the second capacitor is charged only with a negative voltage. In order to regulate the operation of the mechanical oscillator, the regulating device (52) comprises a charge pump (60) arranged to transfer electric charges between the two capacitors as a function of a temporal drift of the mechanical oscillator relative to a time base.

Description

Description

Technical Field [0001] The present invention relates to a timepiece comprising a mechanical oscillator associated with a system for regulating its average frequency. The regulation is of the electronic type, that is to say that the control system comprises an electronic circuit connected to an auxiliary oscillator which is arranged to provide a high precision electric clock signal. The control system is arranged to correct any temporal drift of the mechanical oscillator relative to the auxiliary oscillator.

In particular, the mechanical oscillator comprises a mechanical resonator formed by a sprung balance and a maintenance device formed by a conventional exhaust, for example Swiss anchor. The auxiliary oscillator is formed in particular by a quartz resonator or by a resonator integrated in the electronic control circuit.

BACKGROUND [0003] Movements forming timepieces as defined in the field of the invention have been proposed in some prior documents. Patent CH 597 636, published in 1977, proposes such a movement with reference to FIG. 3. The movement is equipped with a sprung balance resonator and a conventional maintenance device comprising an anchor and an escape wheel in kinematic connection with a spring-loaded barrel. This watch movement comprises a system for regulating the frequency of the mechanical oscillator. This control system comprises an electronic circuit and an electromagnetic assembly formed of a flat coil, arranged on a support under the beam of the balance, and two magnets mounted on the balance and arranged close to each other so as to both pass over the coil when the oscillator is on.

The electronic circuit comprises a time base comprising a quartz resonator and for generating a reference frequency signal FR, this reference frequency being compared with the frequency FG of the mechanical oscillator. The detection of the frequency FG is carried out via the electrical signals generated in the coil by the pair of magnets. The control circuit is arranged to be able momentarily to generate a braking torque via a magnet-coil magnetic coupling and a switchable load connected to the coil. Document CH 597 636 gives the following teaching: "The resonator thus formed must have a variable oscillation frequency depending on the amplitude on either side of the frequency FR (isochronism defect)". It is therefore taught that a variation of the oscillation frequency of a non-isochronous resonator is obtained by varying its amplitude of oscillation. An analogy is made between the amplitude of oscillation of a resonator and the angular velocity of a generator comprising a rotor provided with magnets and arranged in a cog of the watch movement to regulate its operation. As a braking torque decreases the rotational speed of such a generator and thus its rotation frequency, it is here only considered to be able to reduce the oscillation frequency of a necessarily non-isochronous resonator by applying a torque braking decreasing its amplitude of oscillation.

To perform an electronic control of the frequency of the generator, respectively the mechanical oscillator, it is provided in a given embodiment that the load is formed by a switchable rectifier via a transistor that recharges a power supply capacity during the braking pulses, to recover the electrical energy in order to supply the electronic circuit. The constant teaching given in document CH 597 636 is as follows: When FG> FR the transistor is conductive; a power Pa is then taken from the generator / oscillator. When FG <FR, the transistor is non-conductive; no more energy is drawn from the generator / oscillator. In other words, it regulates only when the frequency of the generator / oscillator is greater than the reference frequency FR. This regulation consists of braking the generator / oscillator in order to reduce its frequency FG. Thus, in the case of the mechanical oscillator, those skilled in the art understand that regulation is possible only when the mainspring is heavily armed and the free oscillation frequency (natural frequency) of the oscillator mechanical is greater than the reference frequency FR, as a result of a desired isochronism defect of the selected mechanical oscillator. There is therefore a double problem, namely the mechanical oscillator is selected for what is normally a defect in a mechanical movement and the electronic control is functional only when the natural frequency of this oscillator is greater than a nominal frequency.

The patent application EP 1 521 142 also deals with the electronic control of a sprung balance. The control system proposed in this document is similar in its general operation to that of patent CH 597 636.

The patent application EP 1 241 538 teaches that the moment of braking of the mechanical oscillator, during an alternation of any oscillation of the latter, allows either to decrease the value of the oscillation period. in progress, to increase it. To do this, there is provided an electromagnetic magnet-coil assembly and a control circuit which is arranged to make conductive or not the coils during certain time intervals. In general, a braking of the mechanical oscillator, by the generation of an electric power in the coils during a magnet-coil coupling, during a period of oscillation generates an increase in the corresponding period when this braking occurs before the passage of the mechanical resonator by its neutral point (rest position), or a decrease in the corresponding period when the braking occurs after the passage of the mechanical resonator by its neutral point. This observation is remarkable in view of the teaching that prevailed at the time.

Regarding the implementation of an electronic control taking advantage of the above-mentioned finding, the document EP 1 241 538 proposes two embodiments. In these two embodiments, there is provided a piezoelectric system associated with the exhaust to detect a tilting of its anchor in each oscillation period. With such a detection system, it is intended, on the one hand, to compare the oscillation period with a reference period, defined by a quartz oscillator, to determine whether the timepiece's running has a advance or delay and, secondly, to determine in alternate alternation the passage of the mechanical oscillator by its neutral point. In the first embodiment, according to whether the time drift corresponds to an advance or a delay, provision is made to make the coils conductive for a certain time interval respectively before or after the passage through the neutral position of the mechanical oscillator in an alternation . In other words, it is provided here to short-circuit the coils before or after the passage through the neutral position, depending on whether the regulation requires respectively an increase or a decrease in the oscillation period.

In the second embodiment, it is intended to supply the control system by periodically taking energy from the mechanical oscillator via the electromagnetic assembly. For this purpose, the coils are connected to a rectifier which is arranged to recharge a capacitor (storage capacity), which serves as a power source for the electronic circuit. The electromagnetic assembly is that given in FIGS. 2 and 4 and the electronic circuit is shown schematically in FIG. 5 of this document. The only indications given for the operation of the control system are as follows: 1) the coils are made conductive during constant time intervals which are centered on respective passages of the mechanical resonator (balance spring) by its neutral position (middle position alternations); 2) during these time intervals an induced current is rectified and stored in the capacitor; and 3) during said time intervals, the period of oscillation of the balance spring can be effectively controlled by adjusting the value of the power generated by the induced current, without further details given.

It may be thought that the choice of conduction intervals of the coils centered on the neutral positions of the mechanical resonator is intended not to induce parasitic temporal drift in the mechanical oscillator by taking energy from the latter for power the electronic circuit. By making the coils conductive for the same duration before and after the passage through the neutral position, the author may think to balance the effect of a braking preceding such a passage by the neutral position with the effect of braking according to this passage so as not to change the oscillation period in the absence of a correction signal of the control circuit involved following the measurement of a time drift. It is highly doubtful that this can be achieved with the disclosed electromagnetic assembly and a conventional rectifier connected to a storage capacitor. First, the recharge of this storage capacity depends on its initial voltage at the beginning of a given time interval. Then, the induced voltage and the current induced in the coils vary in intensity with the angular speed of the sprung balance, this intensity decreasing when moving away from a neutral position where the angular velocity is maximum. The disclosed electromagnetic assembly makes it possible to determine the shape of the induced voltage / induced current signal. Although the angular position of the magnets relative to the coils for the neutral position (rest position) is not given and we can not deduce a teaching on the phase of the signal, it can be deduced that the recharge of the capacitance of Storage will normally take place for the most part before passing through the neutral position. Thus, it results in a braking which is not symmetrical relative to the neutral position and a parasitic delay in the timepiece market. Finally, as to the adjustment of the power induced during the constant time intervals provided for regulating the running of the timepiece, nothing is indicated. One does not understand how such an adjustment is made, no teaching being given on this subject. SUMMARY OF THE INVENTION [0011] A general objective, within the framework of the development that led to the present invention, was to produce a timepiece, comprising a mechanical movement with a mechanical oscillator and an electronic control system of this oscillator. mechanical, for which it is not necessary to initially displace the mechanical oscillator so that it advances, so as to have a timepiece that has the precision of an auxiliary electronic oscillator (in particular equipped with a resonator to quartz) when the control system is functional and, in the opposite case, the accuracy of the mechanical oscillator corresponding to the best standard. In other words, it seeks to add an electronic control to a mechanical movement also set as precisely as possible so that it remains functional, with the best possible operation, when the electronic control is not active.

The present invention has the primary objective of providing a timepiece of the type described above, in which the control system consumes relatively little electrical energy and thus allows effective self-supply of this control system by a less electrical energy taken from the mechanical oscillator of the timepiece, regardless of the magnitude of a time drift to be corrected within a range of values that it is expected to be able to correct.

Another object is to provide a timepiece of the type described above which is capable, for a defined electromagnetic assembly, of providing electrical power supply and continuously a supply voltage which are sufficient to ensure the smooth operation of the control system, especially in the absence of correction of a time drift.

A particular objective is to provide such a timepiece that is capable, for a defined electromagnetic assembly, of continuously supplying an electrical supply voltage that remains substantially maximum regardless of the correction of a time drift of this timepiece made by the regulation system.

Another particular objective is to ensure the self-supply of the control system without inducing a parasitic time drift, in particular in the absence of a correction of a time drift, or at least so that such a possible parasitic temporal drift remains minimal and negligible.

For this purpose, the present invention relates to a timepiece comprising: - a mechanism, in particular a mechanism for indicating the time, - a mechanical resonator capable of oscillating around a neutral position corresponding to its state of minimum mechanical potential energy, each oscillation of the mechanical resonator defining a period of oscillation and having two successive alternations each between two extreme positions which each define the oscillation amplitude of the mechanical resonator, each alternation having a passage of the mechanical resonator by its neutral position (rest position / minimum mechanical energy position) at a median time and consisting of a first half-alternation between an initial moment of this alternation and its median moment and a second half-alternation between this median moment and a final moment of this alternation. - A mechanical resonator maintenance device forming with the latter a mechanical oscillator which defines the rate of operation of said mechanism, - an electromechanical transducer arranged to be able to convert the mechanical power of the mechanical oscillator into electrical power, particularly when the mechanical resonator oscillates with an amplitude within a useful operating range, this electromagnetic transducer being formed by an electromagnetic assembly comprising at least one coil, mounted on one of the mechanical assembly consisting of the mechanical resonator and its support, and minus one magnet, mounted on the other element of this mechanical assembly, the electromagnetic assembly being arranged to be able to provide a voltage signal induced between the two output terminals of the electromechanical transducer when the mechanical resonator oscillates with an amplitude included in the said useful operating range, - an electric converter connected to the two output terminals of the electromechanical transducer so as to be able to receive an induced current therefrom, this electrical converter comprising a power supply unit arranged to be able to accumulate electrical energy supplied by the electromechanical transducer, this electromechanical transducer and the electrical converter together forming a braking device of the mechanical resonator, - a load connected to or capable of being regularly connected to the power supply unit so that it can be powered by this power unit. supply, - a device for regulating the frequency of the mechanical oscillator, this regulating device comprising an auxiliary oscillator and a measuring device arranged to be able to detect an eventual time drift of the mechanical oscillator relative to the oscillator auxil iaire, the regulating device being arranged to be able to determine if the measured time drift corresponds to at least some advance.

The timepiece according to the invention is characterized in that: the power supply unit comprises a first power supply capacitor and a second power supply capacitor, both arranged for supplying said load, and electric converter is formed by a first electric energy storage circuit, which comprises the first power supply capacitance and which is arranged to be able to recharge this first power supply capacitance only with a voltage having a first polarity at the input of the electric converter , and by a second electrical energy storage circuit which comprises the second power supply capacitance and which is arranged to be able to recharge this second supply capacitance only with a voltage having a second polarity, opposite to the first polarity, in input of the electric converter, the braking device being arranged in such a way that a quantity of electric power supplied during a recharge to the first supply capacity, respectively to the second supply capacity, is greater the greater the voltage level of this first supply capacity, respectively this second supply capacitance is low, the braking device is arranged in such a way that the induced voltage signal present in each oscillation period of the mechanical oscillator, when the amplitude of oscillation is within the useful range of operation, at least a first interval in which this induced voltage signal has the first polarity and at least a second interval in which this induced voltage signal has the second polarity, - the braking device is further arranged such that, for each oscillation of the mechanical transducer with an amplitude in the useful operating range, a recharge of one of the first and second power supply capacity, if any, occurs mainly in the first two half-waves alternately and a recharge of the other of these first and second power supply capacities, if any, takes place for the most part globally. in the two second half-cycles, the regulating device comprises a charge pump arranged to be able to transfer on command electric charges from said one of the first and second supply capacitances to the other, and the regulating device comprises in addition to a control logic of the charge pump which receives as input a measurement signal supplied by the measuring device and which is arranged to activate the charge pump to effect a transfer of a first electric charge of said one of the first and second feed capacitances to said other when the measured time drift c corresponds to said at least some advance.

The transfer of a first electrical charge is intended to increase, at least in a period of oscillation following such a transfer, the recharge of said one of the first and second power supply capacitances and / or decrease the recharge of said other of these first and second power capacitances relative to the hypothetical case where the transfer of the first electric charge would not take place. If during a first sequence of a control method according to the invention such a result is not obtained, this first sequence is repeated until the aforementioned effect. An imbalance is introduced between the recharge of the first feed capacity and the recharge of the second feed capacity, in favor of said one of the first and second feed capacities, with respect to a situation occurring in a stable phase of no correction, that is to say without correction of a temporal drift. In other words, it selectively acts on the recharge of the first and second power supply to promote a recharge thereof in the first half-cycles of at least one oscillation and therefore temporarily reduce the instantaneous frequency of the mechanical oscillator. In a preferred embodiment, the first and second supply capacitors have substantially the same capacitance value and are arranged to jointly feed the load.

In a main embodiment of the invention, the control device is also arranged to determine if the measured time drift corresponds to at least a certain delay. The timepiece is then further characterized by the following specific elements: the charge pump is also arranged to be able to momentarily transfer electrical charges from said other of the first and second supply capacitors to one of these first and second feeding capacities; the control logic circuit of the charge pump is arranged to activate the charge pump to effect a transfer of a second electric charge from said other of the first and second supply capacitors to one of these first and second supply capacitances when the measured time drift corresponds to said at least a certain delay.

In the latter case, the transfer of a second electric charge is provided to increase, at least in a period of oscillation following such a transfer, recharging said other first and second power supply and / or to reduce the recharge of said one of these first and second power supply capacities relative to the hypothetical case where said transfer of this second electric charge would not take place. Again, if during a second sequence of the control method according to the invention such a result is not obtained, this second sequence is repeated until the aforementioned effect. An imbalance is thus introduced between the recharge of the first supply capacity and the recharge of the second supply capacity, in favor of the said other of the first and second supply capacities, relative to a situation occurring in a stable phase of no correction. In other words, it acts selectively on the recharge of the first and second power supply to promote a recharge thereof in the second half-cycles of at least one oscillation and therefore temporarily increase the instantaneous frequency of the mechanical oscillator.

The load arranged at the output of the electrical converter comprises in particular the control device which is powered by the first and second power supply capacitors arranged so as to deliver a supply voltage corresponding to the addition of the respective voltages of these first and second feeding capacities.

Thanks to the characteristics of the watch movement according to the invention, it is possible to regulate, via an auxiliary oscillator comprising for example a quartz resonator, a mechanical oscillator which is otherwise very precise, that momentarily has a frequency slightly too high or too low. The regulation of the frequency consists in momentarily varying the instantaneous frequency of the mechanical oscillator so that its average frequency over time is equal to that of the auxiliary oscillator. It is a very precise regulation that eliminates any temporal drift of the operation of the mechanism in question.

In a preferred embodiment of the invention, the braking device, in particular the electromagnetic assembly of the electromechanical transducer, is arranged so that, in each oscillation period of the mechanical oscillator, a first lobe of the induced voltage signal has a maximum positive voltage for this oscillation period and a second lobe of this induced voltage signal has a maximum negative voltage for this oscillation period, and so that the first voltage lobe and the second voltage lobe. When the said first polarity is positive, the said second polarity is negative, respectively in a first half-cycle and a second half-cycle of one and / or the other of the two half-waves of the oscillation considered, and if said first polarity is negative while said second polarity is positive, respectively in a second polarity e half-alternation and a first half-alternation of one and / or the other of the two alternations of this oscillation considered.

By "voltage lobe" it is understood a voltage pulse which is located entirely above or entirely below a zero value (defining a zero voltage), that is to say a variation of voltage within a certain time interval with either a positive voltage whose positive value goes up then down, or a negative voltage whose negative value goes down then up.

In a general variant, the electromagnetic assembly comprises at least one coil and a magnetized structure formed of at least one magnet and having at least one pair of magnetic poles of opposite polarities, each generating a magnetic flux in the direction of the magnet. a general plane of the coil, this pair of magnetic poles being arranged so that their respective magnetic fluxes pass through the coil with a time shift but with at least partly a simultaneity of the magnetic flux entering the coil and the magnetic flux coming out of the coil. this coil, so as to form the first and second voltage lobes.

In a particular embodiment, the electromagnetic assembly of the timepiece comprises a first pair of bipolar magnets and a first coil and a second pair of bipolar magnets and a second coil, each pair of magnets. bipolar magnets having two respective magnetization axes with opposite polarities and a substantially identical angular aperture, the center axis of the second pair of bipolar magnets and the second coil having a non-zero angular offset which is substantially identical to that provided for between the first pair of bipolar magnets and the first coil. The electromagnetic assembly is arranged in such a way that, when the resonator is at rest, one of the first and second pairs of bipolar magnets is situated at equal angular distance from the first and second coils, this electromagnetic assembly comprising either a plurality of arranged coils of whereby a first center line between the first and second pair of bipolar magnets defines an axis of symmetry for that plurality of coils, ie a plurality of pairs of bipolar magnets arranged so that a second center line between the first and second pairs of bipolar magnets second coil defines an axis of symmetry for this plurality of pairs of bipolar magnets. Finally, the various elements of the electromagnetic assembly are arranged so that the respective induced voltages in the coils in question add constructively.

In a first preferred embodiment, the angular offset is substantially equal to 90 °, the electromagnetic assembly comprising only two coils, namely the first and second coils mentioned above which are angularly offset by 180 °, and two pairs of magnets. bipolar mounted on a balance of the mechanical resonator, namely the first and second pairs of aforementioned magnets also angularly offset by 180 °.

In a second preferred embodiment, there is provided the first and second aforementioned coils which are angularly offset by 120 ° and three pairs of bipolar magnets mounted on the balance of the mechanical resonator with angular offsets of 120 ° between them (c). that is, between a pair of magnets and each of the other two pairs of magnets). The two coils are advantageously arranged in a peripheral area of the watch movement incorporating the mechanical oscillator which is conventionally positioned off-center in this watch movement. It will be noted that the three pairs of magnets arranged radially, at the same distance from the axis of rotation, on a pivoted rocker do not generate weight imbalance, the center of inertia of these three pairs of identical magnets being positioned on the axis of rotation. This second variant is advantageous.

In a third variant, there is provided, in addition to the elements mentioned for the second variant, a third coil also shifted 120 ° relative to each of the other two coils. Note that this latter variant is more cumbersome than the two previous variants and can cause problems of construction of the mechanical clockwork incorporating the mechanical oscillator.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described below in more detail with the aid of the accompanying drawings, given by way of non-limiting examples, in which: FIG. 1 is a general view from above of a timepiece according to the invention, FIG. 2 is a partial and enlarged view of the timepiece of FIG. 1, showing a first embodiment of an electromagnetic transducer which forms a control system incorporated in this timepiece, FIG. 3 represents, for an electromagnetic assembly of a simplified electromagnetic transducer given in FIGS. 4A to 4C for explaining the physical principles of regulation involved in the present invention, the voltage induced in the coil of this electromagnetic assembly when the sprung balance oscillates and the application of a first braking pulse in a certain alternation before the sprung balance passes through its neutral position, as well as the angular speed of the balance and its angular position in a time interval in which the first braking pulse occurs, FIGS. 4A to 4C show, for the electromagnetic transducer considered in FIG. 3, the pendulum at three particular instants of an alternation of the mechanical oscillator during which the first braking pulse is provided, FIG. 5 is a figure similar to that of FIG. 3 with the application of a second braking pulse in a certain alternation after the sprung balance has passed through its neutral position, FIGS. 6A to 6C show the pendulum at three particular moments of an alternation of the mechanical oscillator during which the second braking pulse is provided, FIG. 7 shows the electrical diagram of an electric converter and a device for regulating the mechanical oscillator as arranged in the timepiece of FIG. 1, fig. 8 shows the electronic circuit of a charge pump forming the control device shown in FIG. 7, FIG. 9 shows various electrical signals involved in the electrical diagram of FIG. 7, FIG. 10 is a flowchart of the mode of regulation of the walking of the timepiece according to the invention, FIG. 11 shows the voltage signals across the two power supply capacitors of the electrical converter of FIG. 7, the resulting supply voltage and the current pulses induced across the coil of the electromagnetic transducer for a first control variant of the charge pump, FIG. 12 is similar to FIG. 11, but for a second control variant of the charge pump, FIG. 13 is similar to FIG. 11, but for a third control variant of the charge pump, FIG. 14 shows a second embodiment of an electromechanical transducer incorporated in a timepiece according to the invention, FIGS. 15A-15C show various induced voltage signals provided by the electromechanical transducer of FIG. 14.

Detailed Description of the Invention [0031] Referring to FIGS. 1 and 2, a timepiece object of the present invention will be described below. Fig. 1 is a partial plan view of a timepiece 2 comprising a mechanical movement 4, equipped with a mechanical resonator 6, and a control system 8. The maintenance means 10 of the mechanical resonator are conventional. They include a barrel 12 with a motor spring, an exhaust 14 formed of an escape wheel and a pallet anchor, and an intermediate gear 16 kinematically connecting the barrel to the escape wheel. The resonator 6 comprises a rocker 18 and a conventional coil spring, the rocker being pivotally mounted about an axis of rotation 20 between a plate and a bridge. The mechanical resonator 6 and the maintenance means 10 (also called excitation means) together form a mechanical oscillator. It will be noted that, in general, only the escapement as maintenance means / excitation means of this mechanical oscillator, the energy source and an intermediate gear train are included in the definition of a mechanical clock oscillator. being considered separately. The sprung balance oscillates about the axis 20 when it receives mechanical impulses from the exhaust whose escape wheel is driven by the barrel. The wheel 16 is part of a mechanism of the watch movement whose running is clocked by the mechanical oscillator. This mechanism comprises, in addition to the wheel 16, other mobiles and analog indicators (not shown) kinematically connected to the wheel 16, the displacement of these analog indicators being paced by the mechanical oscillator. Various mechanisms known to those skilled in the art can be provided, in particular mechanisms relating to time.

FIG. 2 is a partial view of FIG. 1, in horizontal section at the balance 18, showing two magnets 22, 23 and a coil 28 forming an electromagnetic assembly 29 according to the invention. The coil 28 is preferably of the wafer type (disk shape having a relatively small thickness). It is arranged on the turntable of the watch movement and conventionally comprises two connection ends E1 and E2. In general, there is provided an electromagnetic assembly which comprises at least one coil and a magnetized structure formed of at least one magnet and having at least one pair of magnetic poles of opposite polarities, each generating a magnetic flux in the direction of a general plane of the coil, this pair of magnetic poles being arranged so that, when the mechanical resonator oscillates with an amplitude within a useful operating range, their respective magnetic fluxes pass through the coil with a time shift but with at least one a simultaneity of the incoming magnetic flux and the outgoing magnetic flux, so as to form a central voltage lobe having a peak value which is maximum.

In the advantageous variant of FIG. 2, the rocker 18 carries, preferably in an area near its outer diameter defined by its serge, a pair of bipolar magnets having respective magnetization axes which are oriented axially with opposite polarities. The magnets are arranged close to one another, at a distance allowing an addition of their respective interactions with the coil 28 with respect to the voltage induced therein (more specifically for generating the aforementioned central voltage lobe ). In a variant not shown, it is possible to arrange a single bipolar magnet with its axis of magnetization parallel to the plane of the balance and oriented tangentially to a geometric circle centered on the axis of rotation 20. In the latter case, the induced voltage signal in the coil may have substantially the same profile as for the pair of magnets described above, but with a lower amplitude since only a portion of the magnetic flux of the magnet passes through the coil when the resonator oscillates. However, conduction elements of the magnetic flux can be associated with the single magnet to direct its magnetic flux substantially in the direction of the general plane of the coil. It should be noted that it is preferable to confine the magnetic flux of the magnet or of the magnets carried by the balance beam by means of a shield formed by parts of the balance, in particular by magnetic parts arranged on both sides of the magnets. in the axial direction so that the coil is partially between these two magnetic parts.

The rocker 18 defines a half-axis 26, from its axis of rotation 20 and perpendicular to the latter, which passes in the middle of the pair of magnets 22 and 23. When the spring balance is in its rest position. , the half-axis 26 defines a neutral position (angular rest position of the sprung balance corresponding to a zero angle) around which the sprung balance can oscillate at a certain frequency, in particular at a free frequency FO corresponding to the frequency of oscillation of the mechanical oscillator not subjected to external force torques (other than the one supplied periodically via the escapement). In fig. 2, the mechanical resonator 6 (shown without its spiral which is located above the section plane) is shown in its neutral position, corresponding to a minimum potential mechanical energy state of the resonator. Note that, in the neutral position, the half-axis 26 defines a reference half-axis 48 which is angularly offset by an angle θ relative to the fixed half-axis 50 which intercepts the axis of rotation 20 and the axis In other words, in projection in the general plane of the balance, the center of the coil 28 has an angular offset θ relative to the reference half-axis 48. In FIG. 2, this angular offset is 120 ° in absolute value. Preferably, the angular offset θ is between 30 ° and 120 ° in absolute value.

Each oscillation of the mechanical resonator defines a period of oscillation and has a first alternation followed by a second alternation each between two extreme positions defining the oscillation amplitude of the mechanical resonator (note that we consider here the oscillating resonator and therefore the mechanical oscillator as a whole, the oscillation amplitude of the balance-spring being defined among other things by the maintenance means). Each alternation has a passage of the mechanical resonator by its neutral position at a median time and a certain duration between an initial moment and a final instant which are respectively defined by the two extreme positions occupied by the mechanical resonator respectively at the beginning and at the end of this alternation. Each alternation consists of a first half-alternation ending at said median instant and a second half-alternation beginning at this median instant.

The system 8 for regulating the frequency of the mechanical oscillator comprises an electronic circuit 30 and an auxiliary oscillator 32, this auxiliary oscillator comprising a clock circuit and for example a quartz resonator connected to this clock circuit . Note that in a variant, the auxiliary oscillator is integrated at least partially in the electronic circuit. The control system further comprises the electromagnetic assembly 29 described above, namely the coil 28 which is electrically connected to the electronic circuit 30 and the pair of bipolar magnets mounted on the balance. Advantageously, the various elements of the control system 8, with the exception of the pair of magnets, are arranged on a support 34 with which they form a mechanically independent module of the watch movement. Thus, this module can be assembled or associated with the mechanical movement 4 that when they are mounted in a watch case. In particular, as shown in FIG. 1, the aforementioned module is attached to a casing ring 36 which surrounds the watch movement. It is understood that the control module can be associated with the watch movement once the latter fully assembled and adjusted, the assembly and disassembly of this module can occur without having to intervene on the mechanical movement itself.

[0037] Referring to FIGS. 3 to 6C, firstly describe the physical phenomenon on the basis of which is based the regulation principle implemented in the timepiece according to the invention. We consider here a timepiece similar to that of FIG. 1, but not subject of the present invention. This particular realization is thus given here only for the exposition of the physical phenomenon which interests us. The following difference will be noted: The mechanical resonator 40, of which only the balance 42 has been represented in FIGS. 4A-4C and 6A-6C, carries a single bipolar magnet 44 whose magnetization axis is substantially parallel to the axis of rotation 20 of the balance, that is to say with an axial orientation. In this case, the half-axis considered 46 of the mechanical resonator 40 passes through the center of rotation 20 and the center of the magnet 44. In the example discussed here, the angle θ between the reference half-axis 48 and the half-axis 50 has a value of about 90 °. The two half-axes 48 and 50 are fixed relative to the watch movement, whereas the half-axis 46 oscillates with the balance and gives the angular position β of the magnet mounted on this balance relative to the reference half-axis, the latter defining the zero angular position for the mechanical resonator. More generally, the angular offset θ is such that an induced voltage signal generated in the coil at the passage of the magnet facing said coil is located, during a first alternation of any oscillation, before the passage of the mid-axis median by the reference half-axis (thus in a first half-cycle) and, during a second alternation of any oscillation, after the passage of this median half-axis by the reference half-axis (so in a second half-alternation).

FIG. 3 shows four graphs. The first graph gives the voltage in the coil 28 as a function of time when the resonator 40 oscillates, that is to say when the mechanical oscillator is activated. The second graph indicates the time tP1 at which a braking pulse is applied to the resonator 40 to make a correction in the operation of the mechanism clocked by the mechanical oscillator. The instant of the application of a pulse of rectangular shape (that is to say of a binary signal) is considered here as the temporal position of the middle of this pulse. There is a variation of the oscillation period during which the braking pulse occurs and thus a point variation of the frequency of the mechanical oscillator. In fact, as seen in the last two graphs of FIG. 3, which respectively show the angular velocity (values in radians per second: [rad / s]) and the angular position (values in radian: [rad]) of the pendulum over time, the temporal variation relates to the only alternation during from which intervenes the braking pulse. It will be noted that each oscillation has two successive alternations which are defined in the present text as the two half-periods during which the rocker is respectively subjected to an oscillation movement in one direction and then an oscillation movement in the other direction. In other words, as already explained, an alternation corresponds to a rocking of the rocker in one direction or the other direction between its two extreme positions defining the amplitude of oscillation.

By braking pulse, it includes an application, substantially during a limited period of time, a certain force torque to the mechanical resonator for braking, that is to say a torque force that s opposes the oscillation motion of this mechanical resonator. In general, the braking torque can be of various natures, in particular magnetic, electrostatic or mechanical. In the embodiment described, the braking torque is obtained by the magnet-coil coupling and therefore corresponds to a magnetic braking torque exerted on the magnet 44 via the coil 28 which is controlled by a control device. Such braking pulses may for example be generated by momentarily short-circuiting the coil. This action is recognizable on the graph of the coil voltage in the time zone during which the braking pulse is applied, this time zone being provided at the occurrence of a voltage pulse induced in the coil by the passage of the magnet. It is obviously in this time zone that the magnet-coil coupling allows a contactless action via a magnetic torque on the magnet fixed to the balance. It is observed that the coil voltage goes down to zero during a short-circuit braking pulse (the voltage induced in the coil 28 by the magnet 44 being shown in broken lines in the aforementioned time zone). Note that the short-circuit braking pulses shown in FIGS. 3 and 5 are mentioned here in the context of the explanations given, since the present invention provides a recovery of the braking energy to power the control device.

In figs. 3 and 5, the oscillation period TO corresponds to a "free" oscillation (that is to say without application of regulation pulses) of the mechanical oscillator. Each of the two alternations of an oscillation period has a duration TO / 2 without disturbance or external stress (in particular by a regulation pulse). The time t = 0 marks the beginning of a first alternation. It will be noted that the "free" frequency FO of the mechanical oscillator is here approximately equal to four Hertz (FO = 4 Hz), so that the period TO = approximately 250 ms.

[0041] Referring to FIGS. 3 and 4A-4C, we will describe the behavior of the mechanical oscillator in a first case. After a first period TO begins a new period T1, respectively a new alternation A1 during which occurs a braking pulse P1. At the initial moment faith begins alternating A1, the resonator 40 then being in the state of FIG. 4A where the magnet 44 occupies an angular position β corresponding to an extreme position (maximum positive angular position An). Then comes the braking pulse P1 at time tP1 which is located before the median time tm at which the resonator passes through its neutral position, FIGS. 4B, 4C representing the resonator respectively at the two successive instants tP1 and tN1. Finally the alternation A1 ends at the final time tF1.

In the first case, the braking pulse is generated between the beginning of an alternation and the passage of the resonator by its neutral position, that is to say in a first half-alternation of this alternation. As expected, the angular velocity in absolute value decreases at the moment of the braking pulse P1. This induces a negative time phase shift TCi in the oscillation period of the resonator, as shown by the two graphs of the angular velocity and the angular position in FIG. 3, a delay relative to the undisturbed theoretical signal (shown in broken lines). Thus, the duration of the alternation A1 is increased by a time interval TCi. The oscillation period T1, comprising the alternation A1, is therefore extended relative to the value TO. This causes a specific decrease in the frequency of the mechanical oscillator and a momentary slowing of the operation of the associated mechanism.

[0043] Referring to FIGS. 5 and 6A-6C, we will describe the behavior of the mechanical oscillator in a second case. The graphs of fig. 5 represent the temporal evolution of the same variables as in fig. 3. After a first period TO begins a new period 12, respectively an alternation A2 during which a braking pulse P2 occurs. At the initial time tD2 begins the alternation A2, the resonator 40 then being in an extreme position (maximum negative angular position not shown). After a quarter period (TO / 4) corresponding to a first half-half cycle, the resonator reaches its neutral position at the median time tN2 (configuration shown in Fig. 6A). Then comes the braking pulse P2 at the instant tP2 which is located after the median moment tN2 at which the resonator passes through its neutral position in the alternation A2, that is to say in a second half-cycle of this alternation. Finally, this alternation ends at the final time tF2 at which the resonator again occupies an extreme position (maximum positive angular position). Figs. 6B and 6C represent the resonator respectively at the two successive instants tN2 and tP2. It will be noted in particular that the configuration of FIG. 6A differs from the configuration of FIG. 4C by the opposite directions of the respective oscillation movements. Indeed, in fig. 4C, the pendulum rotates in a clockwise direction when it passes through the neutral position in the alternation A1, whereas in FIG. 6A this balance rotates counterclockwise when passing through the neutral position in alternation A2.

In the second case considered, the braking pulse is generated, in an alternation, between the median instant at which the resonator passes through its neutral position and the final instant at which this alternation ends. As expected, the angular speed in absolute value decreases at the moment of the braking pulse P2. Remarkably, the braking pulse here induces a positive phase shift TC2 in the oscillator period of the resonator, as shown by the two graphs of the angular velocity and the angular position in FIG. 5, an advance relative to the undisturbed theoretical signal (shown in broken lines). Thus, the duration of the alternation A2 is reduced by the time interval TC2. The oscillation period T2 comprising the alternation A2 is therefore shorter than the value TO. This therefore generates a "punctual" increase in the instantaneous frequency of the mechanical oscillator and a momentary acceleration of the operation of the associated mechanism.

We will describe below, with reference to FIGS. 1 and 2 already described and in FIGS. 7 to 13, a first embodiment of a timepiece according to the invention. This timepiece 2 comprises: a mechanism 12, 16 (shown partially); a mechanical resonator 6 (spiral balance) capable of oscillating around a neutral position corresponding to its state of minimum mechanical potential energy, each alternation of successive oscillations presenting a passage of the mechanical resonator by its neutral position at a median instant and consisting of a first half-alternation between its initial instant and its median instant and a second half-alternation between its median instant and its final moment, - a maintenance device 14 of the mechanical resonator forming with this mechanical resonator a mechanical oscillator which speeds the operation of the mechanism, - an electromechanical transducer arranged to be able to convert the mechanical power of the mechanical oscillator into electrical power into particular when the mechanical resonator 6 oscillates with an amplitude included in a e useful operating range, this electromagnetic transducer being formed by an electromagnetic assembly 29 comprising a coil 28 (only element of the electromagnetic assembly shown schematically in FIG. 7), mounted on the support (in particular the plate of the movement 4) of the mechanical resonator, and a pair of magnets 22, 23 mounted on the mechanical resonator, the electromagnetic assembly 29 being arranged so as to be able to provide a induced voltage signal U, (t) between the two output terminals E1 and E2 of the electromechanical transducer when the mechanical resonator oscillates with an amplitude within the useful operating range, the induced voltage signal being, during each oscillation of the mechanical resonator, positive in at least a first part of the corresponding oscillation period and negative in at least a second part of this oscillation period, - an electric converter 56 arranged at the output of the electromechanical transducer so as to receive said electric power induced, this electric converter comprising a power unit C1 &amp; C2 arranged to be able to accumulate electrical energy supplied by the electromechanical transducer, the electromechanical transducer and the electrical converter together forming a device for braking the mechanical resonator, - a device 52 for regulating the frequency of the mechanical oscillator, control device comprising an auxiliary oscillator 58 &amp; CLK and a measuring device arranged to be able to measure an eventual time drift of the mechanical oscillator relative to the auxiliary oscillator, the control device being arranged to be able to determine if the measured time drift corresponds to at least some advance or to least a certain delay.

Preferably, the electromagnetic assembly 29 also partly forms the measuring device. This measuring device furthermore comprises a bidirectional counter CB and a comparator 64 (of the Schmidt trigger type). The comparator receives at one input the induced voltage signal U, (t) and at the other input a threshold voltage signal Uth whose value is positive in the example given. As in the first embodiment the induced voltage signal U, (t) has for each oscillation of the resonator 6 a single positive lobe LU! which exceeds the value Uth, the comparator outputs a signal "Comp" having a pulse 70 per oscillation period, this signal being supplied on the one hand to a first input "UP" of the bidirectional counter CB and on the other hand to a control logic circuit 62. The bidirectional counter comprises a second input "Down" which receives a clock signal ShOr at a nominal frequency / reference frequency for the oscillation frequency, this clock signal being derived from the auxiliary oscillator which provides a reference digital signal defining a reference frequency. The auxiliary oscillator comprises a clock circuit CLK for exciting the crystal resonator 58 and for providing in return the reference signal which is composed of a succession of pulses respectively corresponding to the oscillation periods of the quartz resonator.

The clock circuit supplies its reference signal to a DIV divider which divides the number of pulses in this reference signal by the ratio between the nominal period of the mechanical oscillator and the nominal reference period of the auxiliary oscillator. The divider thus provides a clock signal Shor defining a setpoint frequency (for example 4 Hz) and having a pulse per set period (for example 250 msec) on the counter CB. Thus, the state of the counter CB determines the advance (if the number is positive) or the delay (if the number is negative) accumulated over time by the mechanical oscillator relative to the auxiliary oscillator with a resolution corresponding substantially to a set period. The state of the counter is supplied to a control logic circuit 62 which is arranged to determine whether this state corresponds to at least some advance (CB> N1, where N1 is a natural number) or at least some delay (CB < - N2, N2 being a natural number).

The electric converter 56 comprises a first circuit D1 &amp; C1 of electrical energy accumulation which is arranged to be able to recharge a first supply capacity C1 of the power unit only with a positive voltage input of the electric converter and a second circuit D2 &amp; C2 of accumulation of electrical energy which is arranged to be able to recharge a second supply capacity C2 of the power supply unit only with a negative voltage input of the electric converter. When charging, the amount of electrical energy supplied by the braking device to the first supply capacity, respectively to the second supply capacity, is greater the greater the level of voltage, in absolute value, of this first supply capacity, respectively of this second supply capacity is low.

A load is connected or capable of being regularly connected at the output of the electrical converter 56 and supplied by the power supply unit which supplies the supply voltages VDd and Vss, this load comprising in particular the control circuit 54 which is powered by the power unit. Preferably, the first and second supply capacitors have substantially the same capacitance value.

The timepiece 2 is remarkable in that the regulation circuit 54 of the regulating device comprises a charge pump 60 arranged to be able to transfer on command electric charges from the first supply capacitor C1 to the second C2 feeding capacity and vice versa. An alternative embodiment of such a charge pump is shown in FIG. 8. This charge pump comprises a multiplexer circuit 66, formed by two switches S1 and S2, and an electric charge transfer circuit comprising a switch S3, a switch S4 and two switchable capacitors CT1 and CT2. The operation of the charge pump, well known to those skilled in the art, will not be described here. The switch S3 and the switches S1, S2 and S4 are controlled by the control logic circuit 62 according to a control method (FIG 10) according to the invention which will be described later.

In a first general variant, the braking device is arranged in such a way that, for each oscillation of the mechanical transducer in the useful operating range, a recharge of the supply capacitance C2 occurs for the most part globally in the first two TM1-TN1, TM3-TN3 and a recharge of the C1 power supply capacity intervenes for the most part globally in the two second half-waves TN0-TM1, TN2-TM3. In a second general variant, the braking device is arranged in such a way that, for each oscillation of the mechanical transducer in the useful operating range, a recharge of the capacitor C1 occurs for the most part globally in the first two half-waves TM1-TN1. , TM3-TN3 and a recharge of the C2 capacity intervenes for the most part globally in the two second half-waves TN0-TM1, TN2-TM3. The control logic circuit 62 is arranged to control the charge pump as a function of the first or second general variant implemented, the transfer between the two supply capacitors being inverted between the first and second general variants for any measured time drift.

In the context of the first general variant which corresponds to the case of FIGS. 9 and 10, the control logic circuit 62 of the charge pump is arranged to activate the charge pump 60 to effect a transfer of a certain electrical charge from the second supply capacitor C2 to the first C1 supply capacity when the measured time drift corresponds to at least some advance (CB> N1), so as to increase, at least in a period of oscillation following such a transfer, the recharge of the second capacitor C2 (as shown in Fig. 9) with respect to the hypothetical case where such a transfer of the certain electrical charge would not take place. Then, the control logic circuit 62 of the charge pump is arranged to also activate the charge pump 60 to effect a transfer of a certain electrical charge from the first power supply C1 to the second capacitance. C2 supply when the measured time drift corresponds to at least a certain delay (CB <- N2), so as to increase, at least in a period of oscillation following such a transfer, the recharge of the first capacitor C1 relative to the hypothetical case where such a transfer of this certain electric charge would not take place.

In FIG. 9 is represented, for the first general variant, the situation occurring following the detection of a certain time drift corresponding to an advance of the gait of the timepiece, that is to say at a frequency of mechanical oscillator greater than the reference frequency. The induced voltage signal Ui (t) corresponds to that generated by the electromagnetic assembly 29 previously described in relation to FIG. 1. On the time axis [t] were given the median moments TNn, n = 0, 1,2, ..., corresponding to the successive passages of the mechanical resonator 6 by its neutral position during oscillations in the range useful operation, and instants TMn, n = 0, 1, 2, ..., corresponding to the successive passages of the mechanical resonator alternately by its two extreme positions where its angular velocity is zero and the direction of its swing is reversed. The winding direction of the coil 28 and the polarities of the two magnets 22, 23 are provided so that, in each oscillation period of the mechanical oscillator, a first voltage lobe LUi of the induced voltage signal Ui (t ) has a maximum positive voltage UM-i for this oscillation period and a second voltage lobe LU2 of this induced voltage signal has a maximum negative voltage UM2 for this oscillation period.

In a first particular variant, shown in FIG. 9, the first voltage lobe and the second voltage lobe are respectively involved in a second half-wave TNn-TMn, n = 0, 1, 2, ..., alternating AO-ι, A1- | of each oscillation period and in a first half-wave TMn-TNn, n = 0, 1, 2, ..., of the other alternation A02, A12 of this oscillation period. In a second particular variant, the second voltage lobe and the first voltage lobe intervene respectively in a second half-wave TNn-TMn, n = 0, 1, 2,..., Of an alternation of each period of time. oscillation and in a first half-alternation TMn-TNn, n = 0, 1, 2, ..., of the other alternation of this oscillation period. It will be noted that a simple inversion of the terminals E1 and E2 of the coil or, in an equivalent manner, of the winding direction of the wire forming this coil generates a change of polarity for the induced voltage so that such an inversion makes it possible to pass from the first variant to the second variant and vice versa.

In the first embodiment, as already mentioned in part previously, the electromagnetic assembly 29 comprises a pair of bipolar magnets, mounted on the balance and having magnetization axes with respective opposite polarities, and a coil secured to the support of the mechanical resonator. A medial half-axis 26 extending from the axis of rotation 20 of the balance and passing through the middle of this pair of magnets defines a reference half-axis 48 when the resonator is at rest and thus in its neutral position. As seen in fig. 9, the pair of magnets and the coil are arranged so that the induced voltage signal Ui (t) generated at the terminals E1, E2 of the coil at the passage of the pair of magnets opposite this coil has a central lobe LU-i, LU2 with a maximum amplitude resulting from a simultaneous coupling of the pair of magnets with the coil. Then, the coil 28 has at its center a non-zero angular offset θ relative to the reference half-axis 48 to generate in each oscillation period of the mechanical resonator the first and second voltage lobes in the second and first half-alternations, respectively. (case of Fig. 9) or in the first and second half alternations, respectively, as previously discussed. The angular offset θ is advantageously between 30 ° and 120 ° in absolute value.

In FIG. 9 are also shown the positive voltage Vc · at the upper terminal (defining VDD) of the supply capacitance C1 and the negative voltage VC2 at the lower terminal (defining VSs) of the supply capacitance C2 (the zero voltage being considered as that of the end E1 of the coil). The supply voltage VAL available is therefore given by VCi-VC2, ie the addition of the respective voltages of the first and second capacitors C1 and C2. In the context of the invention, a load is arranged at the output of the electric converter. It includes in particular the control circuit which is powered by the first and second supply capacitors delivering the supply voltage VAL. Thus, apart from short recharging periods of either of the two power supply capacities, there is a certain gradual decrease (in absolute value) of the voltages Vc ·, and VC2 over time. LU voltage lobes! and LU2 which respectively have the maximum positive induced voltage UMi and the maximum negative induced voltage UM2 (in absolute value) are used to recharge capacitors C1 and C2, respectively.

In the first period TO during which no regulation event occurs, an induced current peak 111 recharges the capacitor C1 in a second half cycle and a current induced foot I12 reloads the capacitor C2 in a first half -alternance. These peaks of induced current correspond to electrical powers generated by the electromechanical transducer in the electromagnetic assembly 29 and absorbed by the electric converter 56. These electric powers thus correspond to mechanical powers provided by the mechanical oscillator. They are converted by the electric converter and consumed by the load associated with it. Thus each induced current peak ΙΝΊ and IN2, N = 1.2, ..., supplied by the electromechanical transducer to the electrical converter corresponds to a braking pulse and therefore to a certain momentary braking torque applied to the mechanical oscillator. According to the physical phenomenon described above with reference to FIGS. 3 to 6, the induced current peaks ΙΝΊ cause a decrease in the duration of the alternations during which they occur, and therefore an increase in the instantaneous frequency of the mechanical oscillator, while the current peaks induces IN2 cause an increase in the duration of the alternations during which they occur, and therefore a decrease in the instantaneous frequency of the mechanical oscillator.

In an operating period during which no regulation event and no particular behavior resulting from such a control event occurs, that is to say in a period corresponding to normal operation without regulation, we therefore have the situation represented in the first oscillation period in FIG. 9 concerning the voltages ν0Ί and VC2 and the charging pulses of the capacitors C1 and C2 respectively by the induced currents Ι1Ί and 112, namely a balanced situation in which a first electrical energy absorbed by the electric converter generally in the first two half-cycles is substantially identical to a second electrical energy absorbed by the electrical converter generally in the two second half-cycles of each oscillation period. Thus, the positive temporal phase shift which occurs globally in the two second half-cycles is compensated by the negative temporal phase shift which occurs globally in the first two half-cycles of each oscillation period. In the particular case shown in FIG. 9, the positive temporal phase shift occurring in the first alternation Α0Ί is compensated by the negative time phase shift which occurs in the second alternation AO2 of the corresponding oscillation period. It is therefore understood that, although the duration of the first half cycle is different from that of the second half cycle, their sum is equal to a natural oscillation period TO of the oscillator not subject to a regulation action.

During the first period TO, the control logic circuit has detected that the time drift measured by the measuring device corresponds to a certain advance in the running of the timepiece. It then operates a control action consisting of transferring a certain electrical charge from the capacitor C2 to the capacitor C1. For this purpose, preferably, the regulating device comprises a circuit for detecting a determined event in the induced voltage signal and a timer circuit connected to the control logic circuit which is arranged to advantageously activate the charge pump in zones temporal out of the appearance of the first and second lobes LUi and LU2 of the induced voltage signal. For this purpose, the "Comp" signal of the comparator 64 is supplied to the control logic circuit, said determined event being the appearance of a pulse 70 in this signal. At the falling edge of a pulse 70, the timer is activated and it then counts a predefined TD time interval then activates the charge pump to transfer a certain electric charge, which causes an increase AV of the voltage VCi and a decrease DV of the VC2 voltage (in absolute value). This creates an imbalance between the VCi and VC2 voltages, one VCi being charged to the detriment of the other VC2 which is partially discharged. Since the induced voltage pulses remain identical over time (in the absence of a fall in amplitude of oscillation or without anisochronism), the absolute difference between VC1 and the maximum positive voltage UMi decreases while the absolute difference between VC2 and the maximum negative voltage UM2 increases, the absolute value of VC2 decreasing. Therefore, during the generation of the voltage lobe LU-i in the alternation Α1Ί, the induced current Ι2η is relatively low, or even zero, whereas during the generation of the voltage lobe LU2 in the alternating A12, the current induced I22 is relatively important, as can be seen in the graph at the bottom of FIG. 9.

By decreasing the electrical energy extracted by the electrical converter during the alternation Α1Ί, decreasing the braking of the oscillator in the second half-waves relative to the previous period TO, which corresponds to a decrease in the phase shift. positive time. In addition, by increasing the electrical energy extracted by the electrical converter during the alternation A12, the braking of the oscillator is increased in the first half-cycles relative to the previous period TO, which corresponds to an increase in the phase shift. negative time. These two variations therefore have an effect that goes in the same direction. Thus, overall, relative to the previous period, the electric charge transfer has generated a negative time phase shift and therefore an increase in the duration of the oscillation period following this transfer. A decrease in the instantaneous frequency of the oscillator is obtained, which makes it possible to correct at least partially the certain advance detected which has led to this regulating action. The flowchart in fig. 10 summarizes the control method implemented in the control logic circuit. In a manner similar to what has just been described, when the control logic circuit detects that the time drift measured by the measuring device corresponds to a certain delay in the running of the timepiece, it then operates an action of control consisting in transferring a certain electrical charge from the capacitor C1 to the capacitor C2. The consequence is the opposite, namely that, in relation to the preceding period, the electric charge transfer generally gives rise to a positive temporal phase shift and therefore a decrease in the duration of the oscillation period following this transfer. This gives an increase in the instantaneous frequency of the oscillator to correct at least partially the detected delay.

FIG. 11 shows a simulation of the operation of a variant of the first embodiment in which the arrangement of the charge pump allows a limited electric charge transfer per cycle, so that the charge pump is controlled so as to effect a succession fast several cycles of transfer of an electric charge when a certain time drift has been detected. In the particular example of FIG. 11, a stepwise increase AV1 of the voltage VCi, respectively a corresponding decrease DV1 of the voltage VC2 are generated over a period of less than one half cycle. The curves 72a and 74a show the evolution of the voltages VCi and VC2. Curve 76a gives the supply voltage, which remains substantially stable. The graph at the bottom of fig. 11 shows the induced current lind which has, as explained above, a succession of pulses INd and IN2, n = 1.2, .... More specifically, outside the regulation period, alternately Ifo pulses and I12 as already described. Following the transfer of electric charge (AV1, DV1), one obtains in the oscillation period directly following such a transfer the pulses I2i and I22 as already described. Finally, we observe a transition period (for example of a duration of three oscillation periods, as in the graph considered) during which there is still an imbalance in the capacity recharge C1 and C2, as seen with the pulses I3i and I32, and therefore a certain additional time phase related to the transfer of the electric charge.

In the variant of FIG. 12, representing the same physical magnitudes as FIG. 11, the control logic circuit is arranged such that, when the measured time drift corresponds to at least some advance, a plurality of distinct transfers (corresponding to the voltage variations AV2n and DV2n, m = 1,2, 3,. .., respectively for voltages VC1, graph 72b, and VC2, graph 74b) of first electrical charges from capacitor C2 to capacitor C1 are performed during a plurality of respective oscillations of the mechanical resonator. In the control period, following the first pair of pulses I2i and I22 already described, a first transition period is observed with pulse pairs I4i and I42 having peak / peak values which progressively increase the difference between the two pulses before a stationary / stationary period with I5-, and I52 pulse pairs having the greatest ratio of peak / peak values. Again it can be seen that the supply voltage VAL, graph 76b, is substantially stable.

In a more sophisticated control method, it is possible to vary, as a function of the measured time drift, the number of oscillation periods during which a certain electric charge transfer is performed. Thus, as soon as a first drift is observed, an electric charge transfer is performed during a sequence of the regulation process in a single oscillation period, whereas as soon as a second temporal drift greater than the first drift is As noted, several electric charge transfers are made in several respective oscillation periods during a sequence of the regulation process. Of course, several predetermined values for the time drift can be stored in the control circuit and the number of cycles of transfer of a certain electric charge by the charge pump is predicted as a function of which predetermined value is detected.

FIG. 13 shows, for the same control method as shown in FIG. 12 and thus the same timepiece, the case where the control circuit detects at least a certain delay in the running of the timepiece. In this case, in order to generate a positive temporal phase shift, the electric charge transfers are successively carried out from the capacitor C1 to the capacitor C2. This generates the desired positive temporal phase shift and therefore a decrease in the duration of a few oscillation periods following this transfer. An increase in the instantaneous frequency of the oscillator is then obtained, which makes it possible at least partially to correct the certain detected delay which has led to this regulating action. More precisely, the control logic circuit is arranged in such a way that, when the measured time drift corresponds to at least a certain delay, a plurality of distinct transfers (corresponding to the voltage variations AV3m and DV3m, m = 1,2,3, ..., respectively for voltages VC2, graph 74c, and VC1, graph 72c) of second electrical charges from capacitor C1 to capacitor C2 are performed during a plurality of respective oscillations of the mechanical resonator. As expected, the graph 76c of the supply voltage VAl shows that it is substantially stable. The pulse pairs I6-1 and I62, I7-, and I72, Ι8η and I82, I9-i and I92 of the current induces lind in the control period have, at their peak / peak values, an inversion, in value absolute, relative to the corresponding pairs of FIG. 12 (respectively to pulse pairs Ι2η and I22, 14η and I42, I5i and I52, I3i and I32).

In order to increase the induced voltage and thus the supply voltage, it is provided in a second embodiment to provide an electromagnetic assembly with two coils arranged on the support of the balance spring and two pairs of bipolar magnets. mounted on the balance, each pair of magnets having a configuration as shown in FIGS. 1 and 2. Advantageously, the second pair of magnets has an angular aperture substantially identical to that of the first pair of magnets. In addition, the second coil and the second pair of magnets have between them a second angular offset substantially identical to the first angular offset between the first coil and the first pair of magnets. The winding directions of the first and second coils and the connection between them and / or the converter are provided so that the two respective induced voltages in the first and second coils add up.

The second embodiment differs essentially from the first embodiment by the arrangement of the electromagnetic assembly forming the electromechanical transducer. With reference to FIGS. 14 and 15A-15C, will be described hereinafter a specific variant of the second embodiment of a timepiece according to the invention. Since the electric converter, the regulation circuit and the regulation method are similar to those of the first embodiment, they will not be described here. The electromagnetic assembly of the electromechanical transducer 82 is specific firstly in that the first and second angular offsets each have a substantially equal value of 90 °. Then, the first and second pairs of bipolar magnets 22A, 23A, 22B, 23B have between them a planar symmetry with symmetrical plane a geometric plane comprising the axis of rotation 20 of the mechanical resonator and a geometric axis passing through the centers. two coils. Finally, the first and second coils 28A, 28B have inverse winding directions in projection in the median general plane, these first and second coils being aligned on a straight line passing through the center of rotation 20 and being connected (respective ends Ε2Ί and E12) so that their respective induced voltages are added to the two output terminals Ε1Ί and E22 of the electromechanical transducer.

As shown in FIGS. 15A to 15C, this specific configuration not only increases the induced voltage supplied to the electrical converter, but in addition to doubling the first and second induced voltage lobes respectively having a maximum positive voltage and a maximum negative voltage. Above each voltage lobe is shown a pair of magnets with the direction of the successive appearance of its two magnets facing the coil considered. Thanks to the specific electromagnetic assembly, two positive voltage lobes are obtained respectively in the respective first half-cycles of the two alternations Α0Ί and A02 of one oscillation period of the mechanical resonator, as well as two negative voltage lobes respectively in the respective second half-cycles of the two alternations Α0Ί and A02. The induced voltage signals LL and U2 provided by the coils 28A and 28B add up, as shown in FIG. 15C, resulting in a doubling of the peak voltage Ûi. Thus, each induced voltage lobe (FIGS. 15A and 15B) participates in the recharging of the two capacitors of the electrical converter and thus in the power supply of the load associated therewith. This results in a regulation of the gait of the timepiece that can occur in the two alternations of one or more period (s) of oscillation following transfers of electrical charges between the two capacities. Note that the comparator of the measuring device generates two pulses per oscillation period, every other pulse being supplied to the bidirectional counter.

Claims (15)

claims 1. Timepiece (2), comprising: - a mechanism, - a mechanical resonator (6) capable of oscillating around a neutral position corresponding to its minimum mechanical potential energy state, each oscillation of the mechanical resonator defining an oscillation period and having two successive alternations each between two extreme positions which define the oscillation amplitude of the mechanical resonator, each alternation having a passage of the mechanical resonator by its neutral position at a median instant and consisting of a first half-alternation between an initial moment of this alternation and its median instant and a second half-alternation between this median moment and a final moment of this alternation, - a maintenance device (14) of the mechanical resonator forming with this resonator mechanical mechanical oscillator which defines the rate of operation of said mechanism, - a transducer electromechanical device arranged to be able to convert the mechanical power of the mechanical oscillator into electrical power when the mechanical resonator oscillates with an amplitude in a useful operating range, this electromagnetic transducer being formed by an electromagnetic assembly (29) comprising at least one coil ( 28), mounted on one of the mechanical assembly consisting of the mechanical resonator and its support, and at least one magnet (22, 23) mounted on the other element of this mechanical assembly, the electromagnetic assembly being arranged in a manner able to provide an induced voltage signal (Ui (t)) between the two output terminals (E1, E2) of the electromechanical transducer when the mechanical resonator oscillates with an amplitude in said useful operating range, - an electric converter (56) connected to the two output terminals of the electromechanical transducer so as to be able to receive from this electromechanical transducer an induced electric current, the electric converter comprising a power supply unit arranged to be able to accumulate electrical energy supplied by the electromechanical transducer, this electromechanical transducer and the electric converter together forming a braking device for the mechanical resonator, load (54) connected or likely to be regularly connected to the electrical converter so that it can be powered by the power supply unit; - a device (8, 52) for regulating the frequency of the mechanical oscillator, this device control device comprising an auxiliary oscillator (58) and a measuring device (64, CB) arranged to be able to detect any temporal drift of the mechanical oscillator relative to the auxiliary oscillator, the control device being arranged to be able to determine whether the time drift measured horn respond to at least some advance; the timepiece being characterized in that the feed unit comprises a first feed capacity (C1) and a second feed capacity (C2), both arranged to feed said load, and the electric converter is formed by a first electric energy storage circuit, which comprises the first power supply capacitance and which is arranged to be able to recharge this first power supply capacitance (C1) only with a voltage having a first polarity at the input of the converter electric, and by a second electric energy storage circuit which comprises the second power supply capacitance and which is arranged to be able to recharge this second power supply capacitance (C2) only with a voltage having a second polarity, opposite to the first polarity, at the input of the electric converter, the braking device being arranged in such a way that a quantity of electrical energy supplied during a recharge to the first supply capacity, respectively to the second supply capacity, is greater the greater the voltage level of this first supply capacity, respectively this second feed capacity is low; in that the braking device is arranged such that said induced voltage signal has in each oscillation period of the mechanical oscillator, when said oscillation amplitude is within the useful operating range, at least a first interval , located in the first two half-waves, wherein said induced voltage signal has said first polarity and at least a second gap, located in the two second half-cycles, wherein said induced voltage signal has said second polarity, the braking device being furthermore arranged so that, for each oscillation of the mechanical resonator with an amplitude in said useful operating range, a recharge of the first feed capacity, if any, takes place for the most part globally in the first two half-wave and a recharge of the second power supply, the case echoes for the most part, intervene globally in the two second half-cycles; in that the regulating device comprises a charge pump (60) arranged to be able to transfer on command electric charges from the first supply capacity to the second supply capacity; and in that the regulating device further comprises a logic circuit (62) for controlling the charge pump which receives as input a measurement signal supplied by the measuring device and which is arranged to activate the charge pump. for performing a transfer of a first electrical charge from the first power supply to the second power supply capacity when the measured time drift corresponds to said at least some advance. 2. Timepiece according to claim 1, characterized in that the control logic circuit is arranged to be able to perform, when the measured time drift corresponds to said at least a certain advance or at least an advance greater than this last, a plurality of transfers of first electrical charges from the first supply capacitance to the second supply capacitance during a plurality of oscillations of the mechanical resonator. 3. Timepiece according to claim 1 or 2, characterized in that the regulating device is also arranged to be able to determine if the measured time drift corresponds to at least a certain delay; in that said charge pump (60) is also arranged to be able to momentarily transfer electrical charges from said second feed capacity to said first feed capacity; and in that the control logic (62) of the charge pump is arranged to activate the charge pump to effect a transfer of a second electrical charge from the second supply capacitance to the first supply capacity when the measured time drift corresponds to the at least a certain delay. 4. Timepiece according to claim 3, characterized in that the control logic circuit is arranged to be able to perform, when the measured time drift corresponds to said at least a certain delay or at least a delay greater than the latter , a plurality of second electric charge transfers from the second supply capacitance to the first supply capacitance during a plurality of oscillations of the mechanical resonator. 5. Timepiece according to any one of claims 1 to 4, characterized in that the first and second feed capacities (C1, C2) have substantially the same capacity value and are arranged to jointly feed said load. 6. Timepiece according to any one of claims 1 to 5, characterized in that said load arranged at the output of the electrical converter comprises in particular said control device (8, 52) which is powered by the first and second power supply capacitors arranged to supply a supply voltage corresponding to the addition of the respective voltages of these first and second supply capacitors. 7. Timepiece according to claim 6, characterized in that the braking device is arranged so that, in each oscillation period of the mechanical oscillator when said oscillation amplitude of the mechanical resonator is in said range of useful operation, a first lobe (LU-i) of the induced voltage signal has a maximum positive voltage (UM-i) for the oscillation period in question and a second lobe (LU2) of this induced voltage signal has a negative voltage maximum (UM2) for this oscillation period, and so that the first voltage lobe and the second voltage lobe occur, if said first polarity is positive while said second polarity is negative, respectively in a first half-cycle and a second half-alternation of one and / or the other of the two alternations of the oscillation considered, and, if said first polarity is negative then that said second polarity is positive, respectively in a second half-wave and a first half-wave of one and / or the other of the two alternations of this oscillation. 8. Timepiece according to claim 7, characterized in that the electromagnetic assembly comprises a magnetized structure formed of said at least one magnet and having at least one pair of magnetic poles of respective opposite polarities, each generating a magnetic flux in direction of a general plane of said at least one coil, said pair of magnetic poles being arranged so that their respective magnetic fluxes pass through the coil with a time shift but with in part a simultaneity of the incoming magnetic flux and the outgoing magnetic flux, to form said first and second voltage lobes. 9. Timepiece according to claim 8, characterized in that the electromagnetic assembly (29) comprises a pair of bipolar magnets (22, 23) mounted on a balance (18) of the mechanical resonator and having axes of respective magnetization with opposite polarities, this pair of bipolar magnets defining said pair of magnetic poles, said coil being secured to a support of the mechanical resonator, a median half-axis (26) extending from the axis of rotation of the balance and passing through the middle of this pair of magnets defining a reference half-axis (48) when the resonator is at rest and thus in its neutral position, the pair of magnets and the coil being arranged so that a pulse of induced voltage generated between the two ends of the coil at the passage of the pair of magnets opposite this coil has a central lobe with a maximum amplitude resulting from a simultaneous coupling of two magnets of the pair of magnets with the coil; and in that the coil has at its center an angular offset (θ) relative to the reference half-axis so that the two central lobes generated in each oscillation period of the mechanical resonator, in said useful operating range, define said first and second lobes of the induced voltage signal. 10. Timepiece according to claim 9, characterized in that said angular offset (θ) is between 30 ° and 120 ° in absolute value. The timepiece of claim 9 or 10 and wherein said pair of bipolar magnets is a first pair (22A, 23A), said coil is a first coil (28A) and said angular offset is a first angular offset; characterized in that said electromagnetic assembly further comprises at least a second pair of bipolar magnets (22B, 23B) mounted on said balance at the same radial distance from the axis of rotation as the first pairs of bipolar magnets and having axes respective magnetizations with opposite polarities and an angular aperture substantially identical to that of the first pair of bipolar magnets, and at least one second coil secured to the support of the mechanical resonator and whose center has with the reference axis of the second pair of bipolar magnets a second angular offset substantially identical to the first angular offset; in that, when the resonator is at rest, one of the first and second pairs of bipolar magnets is located at an equal angular distance from the first and second coils, said electromagnetic assembly comprising either a plurality of coils arranged so that a first axis median between the first and second pairs of bipolar magnets defines an axis of symmetry for this plurality of coils, ie a plurality of pairs of bipolar magnets arranged so that a second median axis between the first and second coils defines a symmetry for this plurality of pairs of bipolar magnets; and in that the various elements of said electromagnetic assembly are arranged in such a way that the respective induced voltages in the coils in question add constructively. 12. Timepiece according to claim 11, characterized in that the first and second angular offsets each have a value substantially equal to 90 °, said electromagnetic assembly comprising only said first and second coils angularly offset by 180 ° and only said first and second pairs of bipolar magnets also angularly offset by 180 °. 13. Timepiece according to claim 11, characterized in that said electromagnetic assembly comprises said first and second coils which are angularly offset by 120 ° and three pairs of bipolar magnets, one of which is offset by 120 ° with each of the other two . 14. Timepiece according to any one of the preceding claims, characterized in that the electromagnetic assembly also partially forms the measuring device. 15. Timepiece according to any one of claims 7 to 13, characterized in that the regulating device comprises a circuit (64) for detecting a determined event in said induced voltage signal and a timer circuit associated with the logic circuit. control unit which is arranged to activate said charge pump in time zones out of the appearance of the first and second lobes of said induced voltage signal.