EP3579058B1 - Timepiece comprising a tourbillon - Google Patents

Description

Technical area

The present invention relates to timepieces comprising a watch movement equipped with a tourbillon carrying in a cage a mechanical resonator, formed of a balance and a hairspring, and an escapement device. By vortex, we also understand what a person skilled in the art sometimes calls a carousel. In addition, such a watch movement comprises a barrel arranged to accumulate mechanical energy and a gear train kinematically connecting the tourbillon cage to the barrel.

Technological background

Watch movements equipped with a tourbillon have been known for a long time. Such a watch movement and even a watch equipped with such a watch movement is generally called a 'tourbillon'. A particular embodiment of a tourbillon provided with a cage carrying a sprung balance and an anchor, which is arranged to cooperate with a fixed escape wheel coaxial with the cage, is disclosed in the patent application WO 2011/006617 .

In a classic tourbillon, the cage generally functions as a second mobile. It has a second gear and is driven via this second gear by a middle wheel. The cage carries a classic escapement formed by an escapement mobile and an anchor, in particular a Swiss anchor. The force is transmitted to the escapement mobile via its pinion which meshes, like a satellite, with a fixed seconds wheel integral with the plate.

The operation of a conventional Swiss lever escapement is well known to those skilled in the art. The escape wheel has a plurality of teeth which cooperate with two vanes carried by the anchor. Each pallet has at its free end an inclined plane. To generate a maintenance pulse for the sprung balance, one of the teeth of the escape wheel comes to rest tangentially against the inclined plane of one of the two pallets, so as to exert a torque on the anchor which is thus driven in rotation by the escape wheel, the latter being driven in rotation by the rotation of the cage via the fixed seconds wheel. The maintenance pulse ends when the pulse nozzle, in each tooth of the escape wheel, is at the bottom of the inclined plane. Thus, to generate a maintenance pulse, the escape wheel must be able to undergo a rotation over an angular distance corresponding to the angular distance, relative to the axis of rotation of the escape wheel set, of the inclined plane of the pallet with which it interacts with. However, as indicated, the rotation of the escape wheel is intimately linked to that of the tourbillon cage, a kinematic connection being provided between the escape wheel and the tourbillon cage. Consequently, in order to drive the escape wheel in rotation, the tourbillon, which has a relatively high inertia, must be set in rotation. The maintenance pulse transmitted to the balance is therefore limited in intensity by the inertia of the tourbillon and also of the gear train kinematically connecting the tourbillon cage to the barrel. The inertia of the tourbillon cage is related to the escape wheel, which increases the inertia of the latter.

The tourbillon mechanism is known to average vertical positions and therefore improve the rate of a horological movement in a wristwatch when it is worn. However, in a conventional movement, the tourbillon increases the inertia of the escapement device because the tourbillon cage is integral in rotation with the escape wheel. This limits the acceleration that the escape wheel can undergo The impulse given to the balance being dependent on the rotation of the escape wheel, it is not possible to increase the frequency above 5 Hz in such a way. reliable in terms of time. It follows that the possible oscillation frequency for the sprung balance of such a mechanism whirlpool is limited. Thus, the frequency of oscillation of a conventional sprung balance in a tourbillon is generally less than five Hertz (5 Hz) and can in certain specific cases reach 5 Hz. It is usually for example three Hertz. It will be understood that this limits the running precision that can be obtained with a watch movement equipped with a conventional tourbillon.

Thus, the remarkable advantage of the tourbillon for the precision of the rate when worn by a watch which incorporates it is diminished, because of the operation of the classic escapement, by the great inertia which its cage generally presents.

The person skilled in the art is aware of various horological embodiments in which an escapement of the magnetic type is proposed. We can cite patent documents CH 711 402 and EP 3,208,667 , as well as the documents US 3,183,426 , FR 2,075,383 and GB 671 360 cited in this European document. Magnetic exhausts are known for their contactless magnetic interactions which by nature decrease mechanical friction and are thus believed to increase the efficiency of such exhausts.

Summary of the invention

The aim of the present invention is to provide a solution to the problem of the conventional tourbillon mentioned above, so as to make it possible to further increase the chronometric benefit of a tourbillon, in particular to increase the running precision of the watch movement equipped with 'a tourbillon according to the invention by the arrangement of a mechanical resonator in the tourbillon cage, having an oscillation frequency Fo greater than the conventional frequencies, preferably greater than five Hertz (Fo> 5Hz).

To this end, the invention relates to a timepiece comprising a watch movement equipped with a tourbillon, which comprises a cage arranged rotating around a main axis, a barrel, arranged to accumulate mechanical energy, and a cog kinematically connecting the tourbillon cage to the barrel. The tourbillon carries a mechanical resonator, made up of a balance and a hairspring, and an escapement device. According to the invention, the frequency of oscillation of the mechanical resonator is substantially equal to or greater than six Hertz (Fo> = 6 Hz) and the exhaust device is a magnetic exhaust which comprises an exhaust mobile formed by a pinion. exhaust and a magnetic structure or magnetic structures having a general annular shape and centered on an axis of rotation of the exhaust mobile. The magnetic escapement further comprising a magnetic element which, or a plurality of magnetic elements each of which is arranged to have an oscillating movement which is synchronous with the oscillation of the mechanical resonator and which has a non-zero radial component relative to said rotation axis. The magnetic element or each of the magnetic elements of the plurality of magnetic elements is coupled, at least momentarily periodically, with the magnetic structure or the magnetic structures so that the escape mobile performs a rotation by an angular period predetermined at each period of oscillation of the balance. Then, according to the invention, the magnetic escapement presents, in normal operation of the watch movement, alternately phases of energy accumulation, originating from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and phases of transfer of energy accumulated in the magnetic escapement to the magnetic resonator.

• au cours de chaque phase d'accumulation d'énergie, l'élément magnétique ou l'ensemble des éléments magnétiques, qui parmi la pluralité d'éléments magnétiques sont alors couplés à la structure magnétique ou aux structures magnétiques, subit un couple de force magnétique, relativement audit axe de rotation, ayant un sens opposé à celui d'un couple d'entraînement, appliqué par le barillet via la cage du tourbillon au mobile d'échappement, et une intensité inférieure à celle de ce couple de force d'entraînement, de sorte que le mobile d'échappement est apte à tourner d'un certain angle pour permettre l'accumulation d'une certaine énergie potentielle magnétique dans l'échappement magnétique ;
• au cours de chaque phase de transfert d'énergie, l'élément magnétique ou chaque élément de l'ensemble des éléments magnétiques, qui parmi la pluralité d'éléments magnétiques est couplé à la structure magnétique ou aux structures magnétiques lors d'une phase d'accumulation d'énergie précédente, subit une force magnétique radiale (laquelle est de préférence principale), relativement audit axe de rotation, au cours d'une alternance de son mouvement oscillant et dans le sens de la composante radiale de ce mouvement oscillant durant cette alternance, de sorte que l'échappement magnétique convertit en énergie mécanique de l'énergie potentielle magnétique accumulée (de préférence la majeure partie) dans la phase d'accumulation d'énergie précédente pour pouvoir entretenir l'oscillation du résonateur mécanique.

Finally, the magnetic escapement is arranged so that:

• during each energy accumulation phase, the magnetic element or the set of magnetic elements, which among the plurality of magnetic elements are then coupled to the magnetic structure or to the magnetic structures, undergoes a torque of magnetic force , relative to said axis of rotation, having a direction opposite to that of a torque drive, applied by the barrel via the tourbillon cage to the escape wheel set, and an intensity less than that of this driving force couple, so that the escape wheel body is able to rotate by a certain angle to allow the accumulation of a certain magnetic potential energy in the magnetic escapement;
• during each energy transfer phase, the magnetic element or each element of the set of magnetic elements, which among the plurality of magnetic elements is coupled to the magnetic structure or to the magnetic structures during a phase of previous energy accumulation, undergoes a radial magnetic force (which is preferably principal), relative to said axis of rotation, during a alternation of its oscillating movement and in the direction of the radial component of this oscillating movement during this alternation, so that the magnetic escapement converts into mechanical energy the magnetic potential energy accumulated (preferably the major part) in the phase d previous accumulation of energy to be able to maintain the oscillation of the mechanical resonator.

Thanks to the characteristics of the timepiece according to the invention, in particular to the type of magnetic escapement selected to equip the tourbillon, the energy pulses transmitted to the mechanical resonator to maintain it are no longer limited in intensity by the inertia of the tourbillon cage. In fact, even the inertia of the cog no longer influences the generation of these energy impulses. Indeed, only the inertia of the anchor (in the case where a stopper is provided) influences the dynamics of the sustain pulses supplied by the magnetic escapement to the mechanical resonator. It will be noted that the anchor here forms a magneto-mechanical converter. Thus, these sustaining pulses can be shorter, that is to say intervene in very limited time intervals which no longer depend on the inertia of the vortex. These remarkable characteristics make it possible to improve the precision of the rate of the watch movement and in particular to improve the isochronism of the mechanical resonators formed by a sprung balance. In addition, they make it possible to arrange in the tourbillon mechanical resonators having a high quality factor, in particular a sprung balance having a natural frequency of oscillation much higher than that of a conventional sprung balance for a conventional tourbillon. , in particular a natural frequency above 5 Hz.

The magnetic escapement according to the present invention therefore makes it possible to temporally dissociate the periodic transmission of a certain quantity of energy from the barrel to the magnetic escapement, which is arranged to accumulate it momentarily, and the transmission of this accumulated energy from the barrel. magnetic escapement with mechanical resonator.

Thus, thanks to the magnetic escapement as selected in the context of the invention to equip a tourbillon, the sustaining pulses supplied by the magnetic escapement to the mechanical resonator can be generated mainly without rotation of the escape wheel and substantially independent of such rotation. Thus, the inertia of the gear train and the inertia of the tourbillon cage no longer hinder the generation of the maintenance pulses. What is important is the radial nature of the force which intervenes mainly to generate each sustaining pulse after a phase of accumulation of magnetic potential energy in the magnetic escapement, so that the fact that the cage rotates either not or only at a small angle is substantially inconsequential on the generation of sustain pulses. As a result, the tourbillon mechanism equipped with a magnetic escapement according to the invention can deliver sustain pulses of short duration and of relatively high intensity.

In an advantageous embodiment, the mechanical resonator comprises a balance which is pivoted magnetically in the tourbillon cage, which for this purpose comprises two magnetic bearings. This particular variant makes it possible, in addition to the various advantages provided by the selected magnetic escapement, to greatly limit the operating differences of the mechanical resonator between the horizontal positions and the vertical positions (the latter being averaged by means of the tourbillon). It will therefore be understood that it thus becomes possible to obtain a tourbillon watch having very high operating precision.

Brief description of the figures

• La Figure 1 est une vue partielle en perspective d'un premier mode de réalisation d'une pièce d'horlogerie selon l'invention, laquelle est formée par un mouvement équipé d'un tourbillon;
• La Figure 2 est une vue partielle de dessus du mouvement horloger de la Figure 1 avec quelques éléments enlevés pour faciliter la vue d'éléments importants pour l'invention;
• La Figure 3 est une vue en coupe du mouvement horloger de la Figure 1, selon le trait de coupe III-III indiqué à la Figure 2;
• La Figure 4 est une vue en coupe du mouvement horloger de la Figure 1, selon le trait de coupe IV-IV indiqué à la Figure 2;
• La Figure 5 donne les deux courbes de l'énergie potentielle magnétique dans l'échappement magnétique de la Figure 2, en fonction de la position angulaire du mobile d'échappement, pour l'arrêtoir positionné respectivement dans l'une et l'autre de ses deux positions de repos;
• Les Figures 6 à 9 représentent partiellement le résonateur mécanique et l'échappement magnétique, incorporés dans le tourbillon du premier mode de réalisation, dans quatre positions différentes lors d'une alternance du résonateur mécanique;
• La Figure 10 est une coupe partielle, similaire à celle de la Figure 3, d'un deuxième mode de réalisation de l'invention;
• La Figure 11 est une représentation schématique partielle d'une première variante du premier ou deuxième mode de réalisation, dans laquelle seuls le balancier et l'échappement magnétique incorporés dans le tourbillon ont été représentés;
• La Figure 12 montre une deuxième variante de réalisation du premier ou deuxième mode de réalisation de l'invention;
• La Figure 13 montre le résonateur mécanique et l'échappement magnétique, porté par la cage d'un tourbillon, d'un troisième mode de réalisation de l'invention; et
• La Figure 14 représente, pour l'échappement magnétique de la Figure 13, des courbes d'énergie potentielle magnétique définie par la structure magnétique et alternativement deux éléments magnétiques fixés au balancier et interagissant avec la structure magnétique.

The invention will be described below in more detail with the aid of the appended drawings, given by way of non-limiting examples, in which:

• The Figure 1 is a partial perspective view of a first embodiment of a timepiece according to the invention, which is formed by a movement equipped with a tourbillon;
• The Figure 2 is a partial top view of the watch movement of the Figure 1 with some elements removed to facilitate the view of elements important to the invention;
• The Figure 3 is a sectional view of the watch movement of the Figure 1 , according to the cut line III-III indicated in Figure 2 ;
• The Figure 4 is a sectional view of the watch movement of the Figure 1 , according to the cutting line IV-IV indicated in Figure 2 ;
• The Figure 5 gives the two curves of the magnetic potential energy in the magnetic escapement of the Figure 2 , depending on the angular position of the exhaust mobile, for the stopper positioned respectively in one and the other of its two rest positions;
• The Figures 6 to 9 partially show the mechanical resonator and the magnetic escapement, incorporated in the tourbillon of the first embodiment, in four different positions during an alternation of the mechanical resonator;
• The Figure 10 is a partial cut, similar to that of the Figure 3 , of a second embodiment of the invention;
• The Figure 11 is a partial schematic representation of a first variant of the first or second embodiment, in which only the balance and the magnetic escapement incorporated in the tourbillon have been shown;
• The Figure 12 shows a second variant embodiment of the first or second embodiment of the invention;
• The Figure 13 shows the mechanical resonator and the magnetic escapement, carried by the cage of a tourbillon, of a third embodiment of the invention; and
• The Figure 14 represents, for the magnetic escapement of the Figure 13 , curves of magnetic potential energy defined by the magnetic structure and alternately two magnetic elements attached to the balance and interacting with the magnetic structure.

Detailed description of the invention

Using the Figures 1 to 11 , a first embodiment of the invention and in particular the specific operation of the magnetic escapement incorporated in the tourbillon of the invention will be described below.

The timepiece comprises a horological movement 2 equipped with a tourbillon 4 comprising a cage 6 arranged to rotate around a main axis 8, a barrel 10 arranged to accumulate mechanical energy and a gear 11 connecting kinematically the tourbillon cage to the barrel. The tourbillon carries a mechanical resonator 14, formed of a balance 16 and a hairspring 15, and an escapement device 18. The tourbillon is pivoted between a plate 3 and a bridge 9. The escape device consists of a magnetic escapement which comprises an escapement mobile 20 formed of an escapement pinion 24 and a first escape wheel 22, the latter comprising a first magnetic structure 26 having a generally annular shape and centered on an axis of rotation 28 of the escape unit.

The magnetic escapement comprises a stopper 30 which momentarily couples, in each alternation of the oscillation of the mechanical resonator 14, this mechanical resonator to the exhaust mobile 20. This stopper and the exhaust mobile are pivoted between a part of the cage. 6 and an exhaust bridge 19 carried by this cage. The stopper undergoes, when the mechanical resonator oscillates, a back and forth movement interspersed with rest phases where the stopper is stopped alternately in two rest positions where it is respectively in abutment against two pins 36 and 37.

In the variant shown, the stopper is formed by an anchor which carries two magnetic elements 32 and 33 each arranged so as to present an oscillating movement which is synchronous with the oscillation of the mechanical resonator and which is oriented mainly in a radial direction relative to the axis of rotation 28 of the anchor. The two magnetic elements are similar and located on the same side of the escape wheel 22. They are both coupled simultaneously in a similar manner to the first magnetic structure, which is arranged so that these two magnetic elements are coupled with it. continuously (or almost continuously) and so that their respective magnetic couplings add up. The operation of this magnetic escapement will be described in more detail below.

In the variant shown, the escapement mobile 20 comprises a second wheel 38 comprising a second magnetic structure 40 which has planar symmetry with the first magnetic structure 26 and which is located at a distance from the latter so as to allow the two magnetic elements 32 and 33 to be located, when they oscillate, at least momentarily between the first and second magnetic structures. The two magnetic elements 32 and 33 interact, in a similar manner, simultaneously with the first and second magnetic structures, so that the effects add up. The two magnetic elements are coupled with the first and second magnetic structures so that the escapement mobile performs a rotation of a predetermined angular period at each period of oscillation of the balance 16. The first and second magnetic structures and are formed respectively. a first permanent magnet and a second permanent magnet which each have an axial magnetization and the same polarity. The two magnetic elements of the anchor are each formed by a permanent magnet having axial magnetization and reverse polarity relative to the first and second magnets, so as to undergo a magnetic repulsion force with each of the two magnetic structures.

Preferably, the first and second wheels 22 and 38 respectively carry a first ferromagnetic structure 44 and a second ferromagnetic structure 46 which respectively cover the first and second magnetic structures on the two outer sides of the assembly consisting of these first and second magnetic structures, so as to form in combination with a few fixing pins (see Figure 3 ) rising from each of the two ferromagnetic structures, some shielding of the first and second magnetic structures and of each magnetic element located between them and thus magnetically coupled with them. The two ferromagnetic structures respectively form two supports for the two magnetic structures. In the variant shown, since the two magnetic elements are continuously coupled with the first and second magnetic structures and therefore remain located between the two ferromagnetic structures, the magnetic escapement is partially shielded. In addition, the magnetic fields of magnetic structures and magnetic elements are confined by the first and second ferromagnetic structures.

In general, the magnetic escapement is arranged so as to present, in normal operation of the watch movement, alternately phases of energy accumulation, originating from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and phases of transfer of energy accumulated in the magnetic escapement to the magnetic resonator. Each energy accumulation phase and the energy transfer phase which follows it occur during a time interval equal to half of a period of oscillation of the mechanical resonator.

In the context of the first embodiment, the arrangement of the magnetic escapement mentioned in the previous paragraph and the operation of this magnetic escapement will be described below with the aid of the Figures 5 to 9 . The Figure 5 shows two energy curves magnetic potential 66 and 68, respectively for the two rest positions of the anchor 30 where the latter is respectively resting against the stops 36 and 37, which each correspond to the magnetic potential energy E _PM in the magnetic escapement in function of the angle θ giving the angular position of the exhaust mobile 20 and therefore of the magnetic structures 26 and 40 (it will be noted that this angle θ is measured according to the direction of rotation of the exhaust mobile, namely the clockwise direction in the example shown in Figures 6 to 9 ). A magnetic escapement of the type selected for the first embodiment of the invention is disclosed in the patent application EP 3 208 667 A1 . Its operation and the characteristics specific to this operation which are used in the context of the present invention will be described below. The Figures 6 to 9 show four successive instants of an alternation of the balance 16 and an alternation of the anchor 30 which is momentarily coupled to this balance.

First, the two magnetic structures 26 and 40 together define, in each of the two rest positions of the anchor 30, increasing portions of magnetic potential energy PC1, respectively PC2 for the magnetic elements 32 and 33 of the anchor 30 which are both coupled, here continuously, to the two magnetic structures. In the variant described, these increasing portions are defined substantially by a magnetic track 58 which each of the two magnetic structures 26 and 40 comprises, this magnetic track having a particular line, alternately entering and exiting relative to a median geometric circle. During normal operation of the watch movement, this particular line is adapted to an accumulation of potential magnetic energy during a rotation of the escapement mobile over a certain angular distance, while the anchor is alternately in its two positions. rest. Each magnetic track 58 is formed by the permanent magnet which constitutes the corresponding magnetic structure, this permanent magnet being arranged in magnetic repulsion with the permanent magnets which constitute the two magnetic elements 32 and 33, as already described.

The increasing portions PC1 and PC2 thus define angular ramps for the accumulation of magnetic potential energy in the magnetic escapement. During each energy accumulation phase, the two magnetic structures 26, 40 and therefore the exhaust mobile undergo a torque of magnetic force (shown diagrammatically in Figures 8 and 9 by two tangential arrows FT) having a direction opposite to the direction of rotation of the escapement mobile (given in these figures by a circular arrow), that is to say opposite to a driving torque applied by the barrel via the tourbillon cage to the exhaust mobile, and an intensity less than that of this driving torque, so that the exhaust mobile rotates through a certain angle to allow the accumulation of a certain magnetic potential energy in the magnetic exhaust. It will be noted that the two magnetic elements 32 and 33 undergo, in reaction, each a magnetic force FM1, respectively FM2 having, on the one hand, a non-zero tangential component relative to the axis of rotation of the exhaust mobile (c ' ie a component tangent at all points to a geometric circle centered on the axis of rotation 28). On the other hand, these magnetic forces FM1 and FM2 are oriented so that the anchor also undergoes a torque of magnetic force, which maintains the fork 52 in support against the stop pin 36, respectively 37 depending on whether the anchor is in one to the other of its two rest positions in the phase of energy accumulation considered. To the Figure 8 , which shows a situation of the magnetic escapement substantially at the start of an energy accumulation phase, the magnetic forces FM1 and FM2 are oriented so that the torque of magnetic force applied to the anchor is greater than the torque of magnetic force applied to this anchor at the end of an energy accumulation phase (situation corresponding to that of the Figure 6 , but already visible at the Figure 9 showing an intermediate situation of the magnetic escapement during an energy accumulation phase).

During each energy accumulation phase, it can be said that the two magnetic elements 32 and 33 of the anchor, which are coupled to the two magnetic structures 26 and 40, together climb one of the angular energy accumulation ramps. magnetic potential PC1 or PC2, by a certain rotation of the escape mobile, while the anchor 30 is in a rest phase. However, it will be noted that this is an energy of magnetic interaction so that it is the whole 'magnetic structures and magnetic elements' which climbs the angular ramps of accumulation of magnetic potential energy. In the case of a coordinate system linked to the watch movement, it is in fact rather the escapement mobile which climbs the increasing portions PC1 and PC2 of the potential energy curves 66 and 68, since it rotates while the magnetic elements are stationary. However, if we consider a coordinate system associated with the escape mobile and fixed relatively to the latter, then it is indeed the two magnetic elements which climb the increasing portions. We therefore understand that this is equivalent.

To the Figure 5 , it can be seen that the magnetic escapement is arranged so that the increasing portions PC1 of the first magnetic potential energy curve 66 are respectively offset by an angular half-period P / 2 relative to the increasing portions PC2 of the second curve d 'magnetic potential energy 68. Then, the two magnetic structures define for the two magnetic elements 32 and 33, in each of the two rest positions of the anchor, magnetic barriers BM1, respectively BM2 which succeed the increasing portions PC1, respectively PC2 . The magnetic barriers BM1 and BM2 of a magnetic potential energy curve 66, 68 are formed respectively by magnetized areas 60 and 62 which are located alternately on either side of the magnetic track 58. Each barrier magnetic BM1 is thus located angularly between two successive magnetic barriers BM2 (and therefore vice versa).

More precisely, in the variant described, two successive magnetic barriers BM1 or BM2 are angularly offset by an angular period P. The two magnetic elements of the anchor are angularly offset, relative to the axis of rotation 28, substantially by one. angle equal to 3P / 2 (generally an odd number of half-periods P / 2). In each of the two anchor rest positions, when one of the two magnetic elements is coupled with an exiting part of the track 58, the other is coupled with a reentrant part of this track. Then, when the first magnetic element presents itself in front of an external magnetized pad 60, the second presents itself in front of an internal magnetized pad 62, and vice versa.

During normal operation of the watch movement, the magnetic barriers are arranged so as to generate, on the two magnetic elements having climbed a preceding angular ramp, a relatively large torque of magnetic force which is opposed to the driving torque applied by the barrel to the escape wheel set, so as to be able to stop the angular advance of the escape wheel set. For a given torque of mechanical force, the exhaust mobile finally stops at a substantially determined angular position (situation corresponding to the Figure 6 ), corresponding on the Figure 5 at the stable points E ₁ , E ₃ , E _{2N + 1} , with N> 0, alternately on curves 66 and 68. It will be noted that weak rebounds can take place so that the exhaust mobile undergoes a certain oscillation around these stable points, which amortizes fairly quickly under the action of the usual friction with mobile watchmakers. In a preferred variant, the watch movement 2 comprises a rocket 12 for equalizing the torque supplied by the barrel 10 to the tourbillon cage 6, so that the escapement mobile is subjected to a substantially constant torque in the cylinder. useful operating range of the timepiece. Thus, throughout this operating range, the above-mentioned stable points correspond to a potential magnetic energy of the same value.

Then, during each energy transfer phase, the two magnetic elements 32 and 33 each undergo a radial magnetic force FR1 and FR2 (situation corresponding to the Figure 7 ), relative to the axis of rotation 28 of the exhaust mobile, during an alternation of its oscillating movement and in the direction of this oscillating movement during this alternation. It will be noted that this radial magnetic force is generally a radial component of the total magnetic force exerted on each of the magnetic elements. It will be noted that the oscillating movement of each of the magnetic elements is, in the preferred variant which is shown, substantially radial relative to the axis of rotation 28 of the exhaust mobile and therefore of the magnetic structures 26 and 40 which are generally centered on this rotation axis. The axis of rotation of the anchor is positioned for this purpose in the watch movement. The magnetic forces, acting respectively on the magnetic elements of the anchor, which provide mechanical energy to this anchor, in the form of a work of a couple of magnetic force, are therefore here substantially the radial components FR1, FR2, called also radial magnetic forces, respective total magnetic forces.

As in a classic mechanical escapement with Swiss lever, each alternation of the anchor 30 is started by an initial drive of this anchor by the balance via a pin 50 (pin having a truncated disc profile) which is placed between the two horns. of the fork 52 of the anchor. This initial phase allows the magnetic elements 32 and 33 to each undergo an initial radial displacement before they undergo, in a following phase of the considered alternation of their oscillating movement, a drop in magnetic potential energy so that the magnetic escapement undergoes an overall decrease in potential energy magnetic, referenced D1 and D2 at the Figure 5 , during each alternation of the oscillation of the balance 16 and consequently of each alternation of the oscillating movement of the anchor 30. During such an alternation, the anchor passes from one rest position to the other of so that the magnetic potential energy in the magnetic escapement varies from a situation described by curve 66 to a situation described by curve 68 or vice versa, depending on whether the anchor is initially in one or the other of its two rest positions at the beginning of the considered alternation.

The arrangement of the magnetic escapement described above, from which derives the profile of each of the two curves 66 and 68, therefore allows this magnetic escapement to convert into mechanical energy the magnetic potential energy accumulated in the accumulation phase of previous energy to deliver it to the anchor in the form of a torque force that works as the anchor rotates. Thus, the anchor becomes driving and provides an energy pulse to the balance via its fork 50, as in a conventional mechanical escapement, to maintain the oscillation of the balance spring. What is remarkable in the magnetic escapement selected in the context of the invention is that the energy transfer can take place without any rotation of the escapement mobile, as shown in Figure 5 for the particular variant where the escape mobile remains at the same angular position during each alternation of the anchor, the magnetic potential energy at the end of the alternation corresponding to the points E ₂ , E ₄ , E _2N with N> 0 , alternately on curves 68 and 66. It will be noted that depending on the driving torque of the barrel, the inertia of the tourbillon cage and the specific arrangement of the magnetic structures, the escape wheel may undergo a small rotation during alternations of the anchor, especially in their terminal phase. Such a variant is also shown on Figure 5 where the magnetic escapement is at the end of alternation at points E ₂ *, E ₄ *, E _2N * with N> 0. The important thing for the type of magnetic escapement selected, it is not that the escape wheel turns or does not turn during the transmission of an energy impulse to the mechanical resonator, but it is that a certain angular displacement of this one is not necessary to trigger this energy pulse, once the balance is mechanically coupled to the anchor via its fork, and to generate it entirely, so that its intensity does not depend on the inertia of the elements between the barrel and the mobile exhaust, in particular not of the inertia of the tourbillon cage.

It will be noted that the magnetic escapement selected in the context of the first embodiment is substantially at constant force; that is to say that the decreases in magnetic potential energy in the phases of energy transmission to the balance remain substantially constant in the useful operating range of the timepiece. It is a property of the magnetic system of the selected magnetic escapement (see Figure 5 ). Indeed, even in the absence of a device for equalizing the force torque applied to the exhaust mobile by the barrel, the sustain pulses supplied to the mechanical resonator in said useful operating range (torque forces applied by the barrel to the escapement mobile varying within a given range of values) correspond respectively to quantities of energy having similar values. The spindle 12 for equalizing the torque supplied by the barrel to the tourbillon cage / to the escape wheel set therefore serves here to improve the efficiency of the entire system (watch movement).

• des portions croissantes pour l'interaction magnétique entre la structure magnétique ou les structures magnétiques et ledit élément magnétique ou l'ensemble des éléments magnétiques qui, parmi la pluralité des éléments magnétiques, sont couplés à la structure magnétique, respectivement aux structures magnétiques dans la position de repos correspondante de l'arrêtoir, ces portions croissantes étant configurées de manière à pouvoir être gravies cycliquement et périodiquement, lors d'un fonctionnement normal du mouvement horloger, par cet élément magnétique ou par cet ensemble d'éléments magnétiques, et
• des barrières magnétiques qui suivent respectivement les portions croissantes dans la position de repos correspondante de l'arrêtoir, ces barrières magnétiques étant agencées de manière à pouvoir stopper une avance angulaire du mobile d'échappement alors que l'arrêtoir est dans cette position de repos correspondante.

In general, in the context of the first embodiment, the selected magnetic escapement comprises a stopper which momentarily couples, in each alternation of the oscillation of the mechanical resonator, this mechanical resonator to the exhaust mobile, the stopper carrying a magnetic element or a plurality of magnetic elements and undergoing, when the mechanical resonator oscillates, a back-and-forth movement interspersed with rest phases where the stopper is stopped alternately in two rest positions. A magnetic structure or several magnetic structures define in the two rest positions of the retainer respectively a first magnetic potential energy curve and a second magnetic potential energy curve, both as a function of the angle of the exhaust mobile and each presenting:

• increasing portions for the magnetic interaction between the magnetic structure or magnetic structures and said magnetic element or the set of magnetic elements which, among the plurality of magnetic elements, are coupled to the magnetic structure, respectively to the magnetic structures in the position corresponding rest of the stopper, these increasing portions being configured so as to be able to be climbed cyclically and periodically, during normal operation of the watch movement, by this magnetic element or by this set of magnetic elements, and
• magnetic barriers which respectively follow the increasing portions in the corresponding rest position of the stopper, these magnetic barriers being arranged so as to be able to stop an angular advance of the escape wheel set while the stopper is in this corresponding rest position .

Then, the increasing portions of the first magnetic potential energy curve are respectively angularly offset relative to the increasing portions of the second magnetic potential energy curve, each magnetic barrier of one of the first and second magnetic potential energy curves being located angularly between two successive magnetic barriers on the other of these first and second magnetic potential energy curves.

• les phases d'accumulation d'énergie interviennent principalement et respectivement dans les phases de repos successives de l'arrêtoir,
• lors de chaque phase d'accumulation d'énergie, ledit élément magnétique ou l'ensemble des éléments magnétiques, qui parmi la pluralité d'éléments magnétiques est alors couplé à la structure magnétique ou aux structures magnétiques, est susceptible de gravir au moins partiellement une des portions croissantes lors d'une certaine rotation du mobile d'échappement,
• les portions croissantes des première et deuxième courbes d'énergie potentielle magnétique peuvent, lors d'un fonctionnement normal du mouvement horloger, être respectivement et alternativement gravies au moins partiellement lors de phases d'accumulation d'énergie successives.

In addition, the magnetic escapement is arranged so that:

• the energy accumulation phases occur mainly and respectively in the successive resting phases of the retainer,
• during each energy accumulation phase, said magnetic element or all of the magnetic elements, which among the plurality of magnetic elements is then coupled to the magnetic structure or to the magnetic structures, is capable of at least partially climbing one increasing portions during a certain rotation of the exhaust mobile,
• the increasing portions of the first and second magnetic potential energy curves may, during normal operation of the watch movement, be respectively and alternately at least partially climbed during successive energy accumulation phases.

• les phases de transfert d'énergie interviennent respectivement dans les alternances successives du mouvement de va-et-vient de l'arrêtoir,
• cet échappement magnétique subit, lors du fonctionnement normal du mouvement horloger, globalement une diminution d'énergie potentielle magnétique lors de chacune des alternances successives du mouvement de va-et-vient de l'arrêtoir, et
• la diminution d'énergie potentielle magnétique dans l'échappement magnétique résulte principalement d'un travail de la force magnétique radiale exercée sur ledit élément magnétique ou sur chaque élément magnétique de l'ensemble des éléments magnétiques qui, parmi la pluralité d'éléments magnétiques, étaient couplés à la structure magnétique ou aux structures magnétiques lors d'une phase de repos précédente, ce travail de la force magnétique radiale étant ainsi fourni à l'arrêtoir qui est agencé pour le transmettre en majeure partie au résonateur mécanique, de sorte que ce résonateur mécanique peut recevoir une impulsion d'énergie mécanique dans chaque alternance du mouvement de va-et-vient de cet arrêtoir.

Finally, the magnetic escapement is further arranged so that:

• the energy transfer phases occur respectively in the successive alternations of the back and forth movement of the stopper,
• this magnetic escapement undergoes, during normal operation of the watch movement, an overall decrease in magnetic potential energy during each of the successive alternations of the back-and-forth movement of the stopper, and
• the decrease in magnetic potential energy in the magnetic escapement results mainly from a work of the radial magnetic force exerted on said magnetic element or on each magnetic element of the set of magnetic elements which, among the plurality of magnetic elements, were coupled to the magnetic structure or to the magnetic structures during a previous resting phase, this work of the radial magnetic force being thus supplied to the stopper which is arranged to transmit it for the most part to the mechanical resonator, so that this mechanical resonator can receive a pulse of mechanical energy in each alternation of the back and forth movement of this stopper.

The variant of the first embodiment shown comprises six external magnetized pads 60 forming as many magnetic stops to temporarily stop the escape wheel and also six internal magnetized pads 62 also forming as many magnetic stops. It will be noted that the number of external / internal magnetized pads may be different and preferably greater. Thus in another variant, the number of external / internal magnetized pads is equal to ten or twelve. It will also be noted that, in another variant, provision is made to have only internal magnetized pads or, preferably, only external magnetized pads.

In an advantageous variant, shown in Figures 2 and 6 to 9 , mechanical safety is provided in the event of shocks or other strong accelerations that the magnetic escapement may undergo. It is obtained by the teeth 70 integral with the escapement mobile arranged at the level of the arms 54 and 55 of the anchor which respectively carry the two magnets 32 and 33, these teeth being capable of cooperating with two fingers located respectively at the ends of the two. arm. In each rest position of the anchor, if the magnetic barrier described above does not exert a sufficient stopping torque to prevent the exhaust mobile from not crossing it, one of the two fingers then comes into abutment against one of the teeth 70.

As the invention makes it possible to increase the frequency of oscillation of the sprung balance, even greatly, it is provided for this purpose, in particular to maintain the angular speed of the tourbillon cage at one revolution per minute, which the tourbillon carries an intermediate mobile 74, the intermediate wheel 76 of which meshes with the escape pinion 24 and of which the intermediate pinion 78 meshes with the fixed seconds wheel 80 which the watch movement comprises. The intermediate wheel is a wheel that reduces the frequency of rotation of the escape wheel and is here arranged so that the tourbillon cage performs one revolution on itself per minute. In an advantageous variant, the oscillation frequency Fo of the mechanical resonator is greater than five Hertz (Fo> 5 Hz). In variant of the invention this frequency is substantially equal to or greater than 6 Hz (Fo> = 6Hz) and, in a specific variant, the oscillation frequency of the mechanical resonator has a value situated between, including, eight Hertz and twelve Hertz ( 8 Hz = <Fo = <12 Hz). It will be noted that an intermediate mobile is already useful for smaller oscillation frequencies of the sprung balance, for example for three Hertz (Fo = 3 Hz), because the escape mobile performs in the example shown one revolution for six periods of oscillation of the sprung balance, which corresponds to a frequency of rotation much higher than that of a conventional toothed escape wheel.

The frequency of rotation F _Rot of the escape wheel is determined by the frequency of the mechanical resonator Fo and by the number of external magnetized areas 60, respectively by the number of internal magnetized areas 62. In a general variant, the rotation frequency F _Rot (number of revolutions per second) of the exhaust mobile is between, including, a quarter and a sixteenth of the oscillation frequency Fo of the mechanical resonator (Fo / 16 = <F _Rot = <Fo / 4). This amounts to saying that the number N _PA of magnetized pads / of external 60 or internal 62 magnetic stops is between four and sixteen (4 <= N _PA <= 16), because F _Rot = Fo / N _PA . In a first example with a mechanical resonator oscillating at three Hertz (Fo = 3 Hz) and the teeth of the fixed wheel (80) comprising 108 teeth, the intermediate pinion comprises 14 teeth and the intermediate wheel comprises 70 teeth, while the pinion exhaust (24) has 18 teeth. In a second example with a mechanical resonator oscillating at six Hertz (Fo = 6 Hz) and the teeth of the fixed wheel comprising 120 teeth, the intermediate pinion comprises 12 teeth and the intermediate wheel comprises 72 teeth, while the exhaust pinion includes 12 teeth.

To the Figure 10 is shown, in cross section similar to that of the Figure 3 , a second embodiment of the invention. Onne will describe below that the distinctive elements of this second embodiment. It will be noted that the magnetic escapement is identical to that of the first embodiment and that all the variants which have been described for this first embodiment also apply for the second embodiment, which is distinguished by the arrangement of the mechanical resonator 14A which comprises a balance 16A magnetically pivoted in the cage 6A of the tourbillon 4A. The cage comprises for this purpose two magnetic bearings 84 and 86 which are formed respectively by two magnets 88 and 90, the shaft 92 of the balance 16A being provided in ferromagnetic material to ensure its alignment between the two magnets. For the operation of such a magnetic pivoting and various possible variants, reference may be made to the documents EP 2 450 758 , EP 3,109,712 and EP 3,106,933 . What is remarkable with such a magnetic system for the pivoting of the balance in a tourbillon is the fact that it makes it possible to greatly reduce the rate differences between the horizontal positions and the vertical positions of the movement, while the tourbillon allows to average the differences in rate between the various vertical positions.

Two variants of the first and second embodiments will be described below. The first variant is shown on Figure 11 , in a simplified way. The escapement device 18B comprises an anchor 30B and an escapement mobile 20B, formed of a single wheel 22 similar to that of the variants described above and therefore carrying a magnetic structure 26 which will not be described here again. On this Figure 11 , there is shown the median geometric circle 96 around which substantially intervenes each energy pulse supplied to the anchor 30B which transmits it to the mechanical resonator 14B (of which only the balance 16A has been shown schematically). This median geometric circle 96 separates the re-entrant portions of the entering portions of the magnetic track 58 and also the outer stopping areas 60 from the inner stopping areas 62, which form the magnetic barriers described above. More generally, this circle 96 separates two annular and contiguous magnetic tracks 98 and 100 opposite which are located the only magnetic element 32B of the anchor respectively in the two rest positions of this anchor and therefore alternately during the accumulation phases of successive magnetic potential energy in the magnetic escapement. The operation of this magnetic escapement is similar to that already described. The major distinction of this variant lies in the anchor 30B which is provided with a single magnet 32B, arranged in repulsion of the magnetized magnetic structure 26, and in the escape mobile which comprises only a single magnetic structure arranged at a level lower / higher than that in which the magnet oscillates when the watch movement is in operation.

The variant of Figure 12 is distinguished by the material arrangement of various parts forming the 18C magnetic escapement. On the other hand, the operation is similar to that already described, the magnetic structure 26C having in plan substantially the same design as the structure 26. The escape mobile 20C and its wheel 22C, carrying the magnetic structure 26C, differ respectively from the mobile 20B. and its wheel 22 of the previous figure by the fact the structure 26C extends laterally to a core 23, at its periphery, while the structure 26 is arranged on a support disc (with high magnetic permeability or not depending on the variant) . The anchor 30C is, depending on the variant, similar to the anchor 30 or 30B, except for the arrangement of the magnetic elements. More specifically, the anchor 30C comprises at least one pair of similar magnetic elements 32C and 33C (two identical magnets in the example shown) which are located respectively above and below the magnetic structure 26C and which are both coupled in a similar manner. to this magnetic structure and so that their respective magnetic couplings add up. Preferably, each pair of magnets is carried by a support 31 made of a material with high magnetic permeability (in particular ferromagnetic) having a general 'C' shape.

With reference to Figures 13 and 14 , a third embodiment of the invention will be described below which is characterized by a magnetic escapement 118 without a stopper, the escape mobile 120 being directly magnetically coupled to the mechanical resonator 114 (shown schematically) whose balance 116 carries the magnetic elements 102 and 103. The balance is associated with a hairspring 115. The tourbillon cage 106 is shown schematically by a block to which is fixed one end of the hairspring and which carries the balance 116 and the mobile 120, which are arranged pivoting in the cage 106, respectively around two axes of rotation 8 and 28 as in the two previous embodiments. The escapement mobile 120 rotates continuously and synchronously with the oscillation of the mechanical resonator (that is to say, the escape wheel rotates by a predetermined angular period during each period of oscillation of the balance 116) . It will be noted that the angular speed of the escapement mobile may exhibit a certain variation during each period of oscillation, in particular depending on whether one is in an energy accumulation phase or an energy transfer phase. .

The magnetic structure 126 is annular and formed alternately of annular sectors 128, in which are arranged magnets in magnetic repulsion with the magnets 102 and 103 when they appear alternately opposite these annular sectors, and of annular sectors 130 formed of a non-magnetic material, such as brass or aluminum. Each pair of adjacent annular sectors defines an angular period of the magnetic structure. Preferably, the magnets of the magnetic structure 126 angularly have an increasing thickness in the direction opposite to the direction of rotation provided for the escape wheel set, so as to have an air gap which decreases between each of them and the magnet 102, 103 which passes above (when the exhaust mobile rotates) and also a magnetic flux which intensifies. For such an advantageous variant, the Figure 14 represents curves level 134 for the magnetic potential energy in the magnetic escapement (here made up of the magnetic structure 126 and the two magnets 102 and 103 integral with the balance) as a function of the relative angular position of one or the other of the two magnets 102 and 103. When the mechanical resonator 114 oscillates, these two magnets oscillate with a phase shift of 180 °, each according to a path represented by the curve 140 in a reference frame of polar coordinates linked to the exhaust mobile. Each annular sector 128 defines a set 128A of level curves, two successive sets 128A being separated by a sector 126A of zero magnetic potential energy defined by an annular sector 126. The level curves 134 are increasing inwardly thereof. ci, i.e. the outer curve has less potential energy than the next curve inside the latter, and so on. For other variant embodiments, reference will be made to the document EP 2,891,930 which describes magnetic escapements of the type selected in the context of the third embodiment.

When the mechanical resonator is in its neutral position (position of minimum mechanical energy shown in Figure 13 ), the two magnets 102, 103 are located on a circle 132 of zero position. When the mechanical resonator oscillates, these two magnets alternately penetrate above the magnetic structure so that the balance is constantly magnetically coupled to this magnetic structure. So that these two magnets alternately experience the same coupling with the magnetic structure, they exhibit an angular shift of an odd number of angular half-periods of the magnetic structure. Thus, the escapement mobile performs a rotation of a determined angular period for each period of oscillation of the balance. In addition, similarly to the previous embodiments, the two magnets 102 and 103 mainly undergo a radial movement, relative to the axis of rotation 28 of the escape wheel set, when the balance oscillates. Preferably, their movement is oriented radially when they cross the zero position circle 132 (corresponding to the outer circle of the magnetic structure). As mentioned, in the variant proposed here, the two magnets 102 and 103 are alternately coupled to the magnetic structure so that they successively undergo magnetic coupling with one of the magnetized annular sectors 128. Thus, the overall magnetic potential energy in l The magnetic escapement 118 is given by the contour lines 134 at the Figure 14 .

We observe at the Figure 14 that the magnetic escapement is arranged so as to present, during normal operation of the watch movement, alternately phases of energy accumulation, originating from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and phases of transfer of energy accumulated in the magnetic escapement to the magnetic resonator. The magnetic escapement defines upward angular ramps 136 for accumulating magnetic potential energy which the magnets 102 and 103 undergo alternately during the continuous rotation of the magnetic structure during successive energy accumulation phases during which they successively and partially climb these ascending angular ramps. As the magnetic interaction force between the magnets 102, 103 and the magnetic structure is oriented perpendicular to the level lines 134, these magnets then experience a magnetic force which is essentially perpendicular to the radius it forms with the axis of rotation 28 Thus, the magnetic structure 126 (and therefore the exhaust mobile) undergoes, during each energy accumulation phase, a couple of magnetic force, relative to its axis of rotation, having a direction opposite to that of 'a driving torque, applied by the barrel via the tourbillon cage to the escapement mobile. It will be noted that the arrangement of the magnets 102, 103 and the magnetized annular sectors 128 is provided so that, in normal operating mode, the intensity of the magnetic force torque is lower than that of the driving torque, so that the cellphone exhaust can continue to rotate and rotate through a certain angle, thus allowing a build-up of potential energy in the magnetic escapement.

The magnetic escapement also defines descending radial ramps 138 of magnetic potential energy which the two magnets 102 and 103 descend alternately after having respectively climbed the ascending angular ramps 136. Like the magnetic force exerted on each magnet 102, 103, descending a descending radial ramp, is oriented perpendicular to the level lines 134, it then undergoes, during energy transfer phases, mainly a radial magnetic force, relative to the axis of rotation 28, during each alternation of the oscillation movement of the mechanical resonator and in the direction of this oscillation movement during this alternation, so that the magnetic escapement then converts into mechanical energy the magnetic potential energy accumulated in the preceding energy accumulation phase to be able to maintain the oscillation of the mechanical resonator. The decrease in magnetic potential energy in the magnetic escapement therefore results mainly from a work of the radial magnetic force exerted alternately on each of the two magnetic elements, this work of the radial magnetic force being transmitted directly to the mechanical resonator, so that this mechanical resonator receives a pulse of mechanical energy in each alternation of its oscillation movement.

The descending radial ramps 138 extend over a certain angular distance so that the continuous movement of the escape wheel has no impact on the particular characteristics sought within the framework of the present invention. In fact, the important thing is that the main radial force which is exerted alternately on each of the two magnets fixed to the balance hardly depends on any rotation of the escapement mobile. Indeed, we observe at the Figure 14 that the arrangement of the magnetic structure makes it possible to generate the energy pulses for the balance without rotation of the escapement mobile. If the latter stopped at the end of the energy accumulation phase, then the balance would nevertheless receive in the form of a pulse the same quantity of energy as that which it receives by undergoing during the energy transfer phases a some rotational movement. In addition, it is observed that this quantity of energy remains almost constant, whether the angular speed of the balance is small or relatively large, as long as the magnetic escapement is arranged so that, in normal operation, it does not reach the top of the rising angular ramps 136 at the end of the energy accumulation phases. This condition is provided for in the magnetic escapement according to this third embodiment.

Finally, it will be noted that a rocket (similar to the rocket 12 shown in the context of the first embodiment) incorporated into the watch movement makes it possible to equalize the torque supplied by the barrel to the tourbillon cage, so that the escapement mobile is subjected to a constant torque during normal operation of the watch movement. In the context of the third embodiment, such a rocket makes it possible to obtain a stationary operating phase over the entire useful operating range of the watch movement, with the amplitude of oscillation of the balance which remains constant and sustain pulses. which provide the balance with the same amount of mechanical energy. All the benefit provided by a rocket for equalizing the torque of force in a conventional mechanical watch movement is brought to the timepiece according to this third embodiment.

Claims (11)

1. Timepiece comprising a timepiece movement (2) fitted with a tourbillon (4) comprising a carriage (6,6A,106) arranged rotating about a main axis, a barrel arranged to accumulate mechanical energy and a geartrain kinematically linking the tourbillon carriage to the barrel, the tourbillon bearing a mechanical resonator (14,14B,114), formed of a balance (16,16A,116) and a balance-spring, and an escapement device; the oscillation frequency (Fo) of the mechanical resonator being substantially equal to or greater than six Hertz (Fo >= 6 Hz) and the escapement device being a magnetic escapement (18) that comprises an escape wheel set (20,20B,20C, 120) formed of an escape pinion and at least one magnetic structure (26,40,26C, 126), which has a general annular shape centred on an axis of rotation (28) of the escape wheel set, this magnetic escapement further comprising a magnetic element or a plurality of magnetic elements (32,33, 32B, 32C,33C, 102,103), this magnetic element or each magnetic element being arranged so as to have an oscillating movement that is synchronous with the oscillation of the mechanical resonator and that has a radial component different to zero relative to said axis of rotation, said magnetic element being coupled with said at least one magnetic structure or each magnetic element of said plurality of magnetic elements being coupled, at least momentarily periodically, with said at least one magnetic structure such that the escape wheel set rotates by a predetermined angular period at each oscillation period of the balance; the magnetic escapement being arranged so as to have, in normal timepiece movement operation, alternately energy accumulation phases, from a conversion of mechanical energy supplied by the barrel into magnetic potential energy in the magnetic escapement, and transfer phases of energy accumulated in the magnetic escapement to the magnetic resonator; the magnetic escapement being arranged such that:

   - during each energy accumulation phase, said at least one magnetic structure is subjected to a magnetic force torque, relative to said axis of rotation, having an opposite direction to that of a drive torque, applied by the barrel via the tourbillon carriage to the escape wheel set, and an intensity less than that of this drive torque, such that the escape wheel set rotates by a certain angle to enable the accumulation of a certain magnetic potential energy in the magnetic escapement;

   - during each transfer phase of energy, said magnetic element or each magnetic element of a set of magnetic elements, that of the plurality of magnetic elements was coupled with said at least one magnetic structure during a preceding energy accumulation phase, is subjected to a radial magnetic force, relative to said axis of rotation, during an alternation of the oscillating movement thereof and in the direction of the radial component of this oscillating movement during this alternation, such that the magnetic escapement then converts into mechanical energy magnetic potential energy accumulated in the preceding energy accumulation phase to be able to maintain the oscillation of the mechanical resonator.
2. Timepiece according to claim 1, characterised in that said magnetic escapement comprises a stopper (30,30B,30C) coupling momentarily, in each oscillation alternation of the mechanical resonator, this mechanical resonator with the escape wheel set (20,20B,20C), the stopper bearing said magnetic element or said plurality of magnetic elements and being subjected, when the mechanical resonator (14,14B) oscillates, to a to-and-fro movement interspersed with rest phases wherein the stopper is alternately stopped in two rest positions; in that said at least one magnetic structure defines in the two rest positions of the stopper respectively a first magnetic potential energy curve (66) and a second magnetic potential energy curve (68), both as a function of the angle of the escape wheel set and each having:

   - increasing portions (PC1,PC2) for the magnetic interaction between said at least one magnetic structure and said magnetic element or a set of magnetic elements that, of the plurality of magnetic elements, are coupled with said at least one magnetic structure in a corresponding rest position of the stopper, these increasing portions being configured so as to be suitable for being climbed, during normal timepiece movement operation, by this magnetic element or by this set of magnetic elements, and

   - magnetic barriers (BM1,BM2) following respectively the increasing portions, these magnetic barriers being arranged so as to be suitable for stopping angular progress of the escape wheel set while the stopper is in the corresponding rest position;

   said increasing portions of the first magnetic potential energy curve being respectively offset angularly relative to the increasing portions of the second magnetic potential energy curve, each magnetic barrier of one of the first and second magnetic potential energy curves being situated angularly between two successive magnetic barriers of the other of these first and second magnetic potential energy curves; the magnetic escapement being arranged such that:

   - the energy accumulation phases occur essentially and respectively in the successive rest phases of the stopper,

   - during each energy accumulation phase, said magnetic element or a set of magnetic elements, which of said plurality of magnetic elements are at that time coupled with said at least one magnetic structure, is suitable for climbing at least partially one of the increasing portions during a certain rotation of the escape wheel set,

   - the increasing portions of the first and second magnetic potential energy curves may, during said normal timepiece movement operation, be respectively and alternately climbed at least partially during successive energy accumulation phases;

   and in that the magnetic escapement is further arranged such that:

   - the transfer phases of energy occur respectively in successive alternations of the to-and-fro movement of the stopper,

   - this magnetic escapement is subjected, during said normal timepiece movement operation, overall to a decrease in magnetic potential energy (D1,D2) during each of the successive alternations of the to-and-fro movement of the stopper, and

   - the decrease in magnetic potential energy in the magnetic escapement results essentially from work of said radial magnetic force (FR1,FR2) applied on said magnetic element or on each magnetic element of a set of magnetic elements that, of the plurality of magnetic elements, were coupled with said at least one magnetic structure during a preceding rest phase, this work of the radial magnetic force thus being supplied to the stopper that is arranged to transmit same mostly to the mechanical resonator, such that this mechanical resonator can receive a mechanical energy impulse in each alternation of the to-and-fro movement of this stopper.
3. Timepiece according to claim 1 or 2, characterised in that the tourbillon further bears an intermediate wheel set (74) of which an intermediate wheel (76) meshes with the escape pinion (24) and an intermediate pinion (78) meshes with a fixed second wheel (80) comprised by the timepiece movement, the intermediate wheel set being a reducer wheel set of the rotational frequency of the escape wheel set and being arranged such that said tourbillon carriage performs one revolution on itself per minute.
4. Timepiece according to claim 3, characterised in that the oscillation frequency (Fo) of the mechanical resonator has a value situated between, inclusive, eight Hertz and twelve Hertz (8 Hz =< Fo =< 12 Hz).
5. Timepiece according to claim 3 or 4, characterised in that the rotational frequency (F_Rot) of the escape wheel set has a value between, inclusive, one quarter and one sixteenth of the oscillation frequency (Fo) of the mechanical resonator (Fo/4 <= F_Rot <= Fo/16).
6. Timepiece according to any of the preceding claims, characterised in that the magnetic escapement comprises at least two similar magnetic elements (32,33) that are situated on the same side of said magnetic structure (26) and that are both coupled simultaneously with this magnetic structure such that the respective magnetic couplings thereof are added together.
7. Timepiece according to any of the preceding claims, characterised in that the magnetic escapement comprises at least one pair of similar magnetic elements (32C,33C) that are situated respectively above and below said magnetic structure (26C) and that are both coupled simultaneously with this magnetic structure such that the respective magnetic couplings thereof are added together.
8. Timepiece according to any of claims 1 to 6, wherein said magnetic structure is a first magnetic structure (26); characterised in that the escape wheel set comprises a second magnetic structure (40) that has a planar symmetry with the first magnetic structure and that is situated at a distance therefrom so as to enable said magnetic element or each magnetic element of said plurality of magnetic elements (32,33) to be situated, during said oscillating movement, at least momentarily between the first and second magnetic structures.
9. Timepiece according to claim 8, characterised in that the first magnetic structure and the second magnetic structure are formed respectively of a first permanent magnet and a second permanent magnet that each have an axial magnetisation and the same polarity; and in that said magnetic element or each magnetic element of said plurality of magnetic elements (32,33) is formed of a permanent magnet having an axial magnetisation and an inverted polarity relative to the first and second magnets, so as to be subjected to a magnetic repulsion force with each of the two magnetic structures.
10. Timepiece according to claim 9, characterised in that said escape wheel set (20) bears a first ferromagnetic structure (44) and a second ferromagnetic structure (46) covering respectively the first and second magnetic structures (26,40) of both external sides of the set of these first and second magnetic structures, so as to form thus a shield of the first and second magnetic structures and of each magnetic element when the latter is situated therebetween and is thus coupled magnetically therewith.
11. Timepiece according to any of the preceding claims, characterised in that the balance (16A) is pivoted magnetically in the carriage (6A) of the tourbillon that comprises for this purpose two magnetic bearings (84, 86).

Images