EP2998801A1 - Magnetic clock escapement and device for controlling the operation of a clock movement - Google Patents

Abstract

The horological magnetic escapement (12) and the regulating device comprising such an escapement comprise a first circular network (3) formed of N1 magnetic lines (4) and a second circular array (9) formed of N2 magnetic lines (10), the number N2 being different from the number N1. The first and second networks are superimposed to define a combined pattern (14) having a magnetic Moire effect. The combined pattern is magnetically coupled to at least one magnet of a resonator to pace the march of a mechanical watch movement. The first magnetic structure is carried by an escape wheel and is rotatable relative to the second fixed magnetic structure with an angular frequency F1. The combined pattern rotates with an angular frequency F2 greater than and equal to the angular frequency F1 multiplied by the number N1 and divided by the number "N equal to this number N1 minus the number N2, ie F2 = F1 · N1 /" N.

Description

Technical area

The present invention relates to the field of devices regulating the movement of a watch movement. In particular, the present invention relates to watchmaking escapements of the magnetic type, the usual functions of which are the maintenance of a resonance mode of a resonator, in particular an oscillation or a continuous rotation of an inertial part of this resonator, and the timing of a counter wheel. In the context of the present invention, the magnetic escapement provides these two functions by means of an escape wheel comprising a magnetic structure, which is magnetically coupled to at least one magnet carried by a part of the resonator undergoing the resonance movement. .

Technological background

The devices for regulating the speed of a wheel, also called rotor, by a magnetic coupling, also called magnetic coupling, have been known for many years. The watch application is also known. Numerous patent applications relating to this field have been filed by Horstmann Clifford Magnetics for inventions by CF Clifford. We will mention the documents FR 1.113.932 and US 2,946,183 . It is also known from the Japanese utility model JPS 5263453U (request No JP19750149018U ) a magnetic escapement of the same type with a direct magnetic coupling between a resonator and an escape wheel formed by a disc supporting two coaxial annular magnetic tracks. These two tracks are substantially contiguous and each comprise magnetic zones formed by individual plates made of high permeability material. magnetic which are arranged regularly with a given angular period, the pads of the first track being offset or out of phase by half a period relative to the pads of the second track. Between the platelets are provided non-magnetic zones, that is to say areas with low magnetic permeability. Areas of high magnetic permeability alternately distributed on one side and the other of a circle corresponding to the rest position (zero position) of at least one magnet carried by the end of a branch d are thus obtained. a resonator of the tuning fork type. The magnet of the resonator is magnetically coupled to these two out-of-phase tracks so that it is alternately attracted by the magnetic zones of the first track and the second track. The escape wheel thus rotates with a speed of rotation such that it advances an angular period of the two tracks at each oscillation of the resonator. The escape wheel provides the energy necessary to maintain the oscillation of the resonator arm carrying the magnetic coupling magnet and this resonator controls or regulates the rotational speed of this escapement wheel, which is proportional at the resonance frequency. There is therefore a magnetic exhaust associated with a resonator which together form a device regulating the running of a counter wheel of a watch movement.

It will be appreciated that the aforementioned magnetic type regulating devices are provided in the prior art for resonators having a single degree of freedom for each resonant-moving part. In general, the resonator is arranged so that the magnet, carried by a member undergoing a resonance movement, oscillates in a substantially radial direction, that is to say substantially orthogonal to the two annular magnetic tracks. In this case, the embodiments mentioned in the prior art have the advantage of having a frequency reduction between the frequency of the oscillation of the resonator and the rotation frequency (in revolutions / s) of the escapement wheel carrying the magnetic structure. No rotated mobile turns or oscillates at a frequency of the order of magnitude of the resonant frequency. The reduction factor is given by the number of angular periods of the annular magnetic tracks.

In the case of these resonators with a single degree of freedom, the aforementioned advantage, resulting from a frequency reduction between the oscillation of the resonator and the rotation of the escape wheel, has a corollary which poses a problem for the magnetic coupling strength. Indeed, to increase the frequency reduction it is necessary to increase the number of periods of the magnetic tracks. For a given diameter of the escape wheel, an increase in the number of periods results in a decrease in the area of the magnetic zones of the annular tracks. Since the magnet of the resonator extends over an angular distance less than half a period of the annular tracks, the dimensions of this magnet must also decrease as the frequency reduction increases. It is therefore understood that the magnetic interaction force between the resonator and the escape wheel decreases; which limits the torque that can be applied to the escape wheel and therefore increases the risk of loss of synchronization between the resonator and the escape wheel. Synchronization here comprises a proportional relationship determined between the resonance frequency and the rotation frequency of the escape wheel.

Finally, it will be noted that watchmaking devices of the magnetic type comprising a resonator with two degrees of freedom, in particular a resonator whose inertial part has a translational trajectory substantially describing a circle, rotating continuously in the same direction, are not known. . A need to design magnetic type escapements for such resonators with two degrees of freedom, with a reduction in the magnetic coupling, however exists in the field of watchmaking. This need seems even crucial when the resonator operates with a relatively high resonance frequency, for example resonators whose resonant organ turns a frequency greater than ten revolutions per second (10 revolutions / s = 10 Hz). Indeed, a mechanical coupling, which would connect such a resonant member to a mobile, would result in rotating this mobile to the resonance frequency. A mobile rotated at a rotation frequency greater than five or six revolutions per second poses a major problem of energy loss by friction and a wear problem at the bearings.

Summary of the invention

The object of the present invention is to respond to the identified needs in the field of clock control devices, in particular for resonators with two degrees of freedom with a circular resonance movement, and to find a solution to the problem related to the weak magnetic interaction in the case of resonators with a single degree of freedom associated with a known magnetic exhaust having a large frequency reduction.

For this purpose, the subject of the present invention is a magnetic escapement equipping a mechanical horological movement and comprising an escape wheel driven by a motor device and associated with a resonator of this mechanical clockwork movement, this escape wheel comprising a first structure magnetic device defining, in a non-zero radial range of this escape wheel, a first periodic pattern with a first angular period P1 such that 360 ° / P1 is equal to a first integer number N1, the magnetic escapement comprising at least one magnet mounted on the resonator and magnetically coupled to the escape wheel so that, when the mechanical watch movement is operating, the magnet has a periodic resonance movement at a resonance frequency and the escape wheel rotates with a frequency proportional to this resonance frequency. The magnetic escapement furthermore comprises a second magnetic structure parallel to the first magnetic structure and defining, in said radial range, a second periodic pattern having a second angular period P2 such that 360 ° / P2 is equal to a second integer number N2 different from the integer N1, the difference in absolute value | ΔN | between the numbers N1 and N2 being a number less than or equal to N / 2, ie | ΔN | <= N / 2, N being the lower number of the numbers N1 and N2. The first and second magnetic structures are arranged such that, when the watch movement is operating, the first magnetic structure rotates relative to the second magnetic structure at a first relative angular frequency F1 _rel . The first periodic pattern and the second periodic pattern are selected so that they generate in said radial range, in projection on a geometrical surface parallel to the first and second magnetic structures, a combined pattern alternately defining at least the number | ΔN | of first zone (s) with a first proportion of magnetic surface and at least this number | ΔN | second zone (s) with a second proportion of magnetic area that is smaller than the first proportion, and that the combined pattern rotates relative to the second magnetic structure with a second relative angular frequency F2 _rel equal to the first angular frequency relative F1 _re! multiplied by the number N1 and divided by the difference ΔN between the numbers N1 and N2, ie F2 _rel = F1 _rel · N1 / ΔN where ΔN = N1-N2.

Angular frequency is understood to be the number of revolutions per second corresponding to the inverse of the period of time of the periodic movement.

In a preferred variant, the magnet has a magnetization axis perpendicular to the geometric surface of said combined pattern.

In a preferred embodiment, the combined pattern defines a periodic combined pattern alternately having the number | ΔN | of first zone (s) and this number | ΔN | second zone (s), one any first zone and a second adjacent zone defining an angular period P3 of this periodic combined pattern whose value is equal to 360 ° divided by the number | ΔN |, ie P3 = 360 ° / | ΔN |.

In an improved embodiment, the magnetic escapement according to the invention comprises a second magnet mounted on the resonator and supported by said resonant portion or by another resonant portion of the resonator. This second magnet is arranged relative to the first magnet on the other side of the first and second magnetic structures, so that it is aligned with the first magnet in a direction substantially parallel to the axis of rotation and has a motion periodic resonance similar to that of the first magnet at the resonant frequency.

In a first variant, the second magnet has a magnetization axis parallel to that of the first magnet and in the opposite direction. In a second variant, the second magnet has a magnetization axis parallel to that of the first magnet and in the same direction.

In an advantageous variant of the improved embodiment, the magnetic escapement comprises a third magnetic structure defining a periodic pattern substantially identical to the periodic pattern defined by the first or second magnetic structure and superimposed thereto, this third periodic structure being integral with rotation with this first or second magnetic structure, in the case where the latter undergoes rotation. The two magnetic structures having the same periodic pattern are located respectively on one side and the other side of the magnetic structure having a different periodic pattern.

In an advantageous variant, the second magnetic structure is fixed relative to the watch movement, the first relative angular frequency F1 _rel defining the angular frequency of the escape wheel relative to this watch movement.

The present invention also relates to a first device regulating the movement of a watch movement comprising a magnetic escapement according to the invention and a resonator, a resonant part supporting said magnet undergoes, during the operation of the watch movement, an oscillation according to a degree of freedom. The resonator is arranged so that the center of the magnet in its rest position is substantially located, for any angular position of the escape wheel, on a zero position circle which is centered on the axis of rotation of the magnet. escape wheel and which is crossed by the degree of freedom of the resonant portion of the resonator. The periodic combined pattern defined by the magnetic escapement is located on a first side of the zero position circle projected perpendicularly into the geometrical surface, the annular region of the first and second magnetic structures defined by said radial range being magnetically coupled to the magnet in a first half cycle of each period of said oscillation so that, for each period of this oscillation, the periodic combined pattern rotates by an angular distance equal to its angular period P3.

In a preferred embodiment of the first regulating device, the periodic combined pattern is a first periodic combined pattern and the radial range is a first radial range, the first and second magnetic structures respectively defining, in a second non-zero radial range of the wheel. escapement located on the other side of the zero position circle relative to the first radial range, a third periodic pattern and a fourth periodic pattern which generate a second periodic combined pattern alternately having the number | ΔN | third zone (s), with a third proportion of magnetic area greater than said second proportion, and this number | ΔN | fourth zone (s) with a fourth proportion of magnetic area that is smaller than the first and third proportions, this second periodic combined pattern having said angular period P3. The second periodic combined pattern is angularly offset by half an angular period P3 relative to the first periodic combined pattern, this second periodic combined pattern also rotating with the relative angular frequency F2 _rel of the first periodic combined pattern, the annular region of the first and second magnetic structures, defined by the second radial range, being magnetically coupled to the magnet in a second alternation of each period of said oscillation.

In a particular variant, the first and second periodic combined patterns are substantially contiguous.

The present invention also relates to a second device for regulating the movement of a clockwork movement comprising a magnetic escapement according to the invention and a resonator having a resonant part supporting said magnet, this resonator being arranged in such a way that this resonant part is subjected to a radial return force relative to the axis of rotation of the escape wheel when the center of the magnet moves away from this axis of rotation, and so that the center of this magnet substantially defines a circle, centered on said axis of rotation, at an angular frequency of resonance when it is distant from this axis of rotation and that this magnet is rotated with a substantially constant torque. The annular region of the first and second magnetic structures, defined by said radial range, is magnetically coupled to the magnet so that the magnet is rotated by a magnetic interaction torque resulting from the combined rotating pattern when a driving torque, in a useful range of the motor torque, is provided to the escape wheel, the angular frequency of the combined pattern being slaved to the resonant angular frequency in this useful range of the torque, which is selected so that the magnetic interaction torque remains less than a maximum magnetic interaction torque and that the circle described by the center of the magnet has a radius in the radial range for any motor torque of this useful range.

In a preferred variant, the resonator is arranged and the useful range of the selected motor torque so that the magnet is entirely superimposed on the combined pattern for any motor torque of this useful range.

Other particular features of the invention will be described below in the detailed description of the invention.

Brief description of the drawings

• La Figure 1 représente schématiquement en plan deux structures magnétiques intervenant dans un premier mode de réalisation d'un échappement magnétique selon l'invention et leur superposition pour former ce premier mode de réalisation;
• La Figure 2 représente schématiquement en plan deux structures magnétiques intervenant dans un deuxième mode de réalisation d'un échappement magnétique selon l'invention et leur superposition pour former ce deuxième mode de réalisation;
• La Figures 3A et 3B montrent, en coupe partielle, un échappement magnétique selon l'invention respectivement dans une première position d'un aimant de cet échappement magnétique et dans une deuxième position de cet aimant;
• La Figure 3C montre un graphe schématique de la variation d'énergie potentielle magnétique de l'échappement magnétique représenté aux Figures 3A et 3B;
• La Figure 4 représente schématiquement un premier mode de réalisation d'un premier dispositif régulateur selon l'invention;
• La Figure 5 représente schématiquement, en coupe, un deuxième mode de réalisation du premier dispositif régulateur selon l'invention;
• La Figure 6 montre deux coupes partielles et un graphe, respectivement similaires à ceux des Figures 3A, 3B et 3C, relatives à un troisième mode de réalisation d'un échappement magnétique selon l'invention;
• La Figure 7 montre deux coupes partielles et un graphe, respectivement similaires à ceux des Figures 3A, 3B et 3C, relatives à un quatrième mode de réalisation d'un échappement magnétique selon l'invention;
• La Figure 8 représente schématiquement, en coupe, un troisième mode de réalisation du premier dispositif régulateur selon l'invention;
• La Figure 9 représente schématiquement une variante de réalisation du dispositif régulateur de la Figure 8;
• La Figure 10 représente schématiquement, en plan, un premier mode de réalisation d'un deuxième dispositif régulateur selon l'invention;
• La Figure 11 représente schématiquement une variante de réalisation du dispositif régulateur de la Figure 10 ; et
• La Figure 12 représente schématiquement, en coupe, un deuxième mode de réalisation du deuxième dispositif régulateur selon l'invention.

The invention will be described hereinafter with the aid of annexed drawings, given by way of non-limiting examples, in which:

• The Figure 1 schematically shows in plan two magnetic structures involved in a first embodiment of a magnetic escapement according to the invention and their superposition to form this first embodiment;
• The Figure 2 schematically shows in plan two magnetic structures involved in a second embodiment of a magnetic escapement according to the invention and their superposition to form this second embodiment;
• The Figures 3A and 3B show, in partial section, a magnetic escapement according to the invention respectively in a first position of a magnet of this magnetic escapement and in a second position of this magnet;
• The Figure 3C shows a schematic graph of the variation of magnetic potential energy of the magnetic escapement represented in Figures 3A and 3B ;
• The Figure 4 schematically represents a first embodiment of a first regulator device according to the invention;
• The Figure 5 schematically shows, in section, a second embodiment of the first regulator device according to the invention;
• The Figure 6 shows two partial sections and a graph, respectively similar to those of Figures 3A, 3B and 3C , relating to a third embodiment of a magnetic escapement according to the invention;
• The Figure 7 shows two partial sections and a graph, respectively similar to those of Figures 3A, 3B and 3C , relating to a fourth embodiment of a magnetic escapement according to the invention;
• The Figure 8 schematically represents, in section, a third embodiment of the first regulator device according to the invention;
• The Figure 9 schematically represents a variant embodiment of the regulating device of the Figure 8 ;
• The Figure 10 schematically represents, in plan, a first embodiment of a second regulator device according to the invention;
• The Figure 11 schematically represents a variant embodiment of the regulating device of the Figure 10 ; and
• The Figure 12 schematically represents, in section, a second embodiment of the second regulator device according to the invention.

Detailed description of the invention

To the Figure 1 is partially shown the construction of a first embodiment of a magnetic escapement 12 equipping a mechanical watch movement and comprising an escape wheel formed of a first magnetic structure 2 defining, in an annular surface, a first circular network 3 having a first integer N1 (N1 = 20 in the example shown) of lines 4 of magnetic material separated by lines defined by vacuum or a substantially non-magnetic material. This first circular network thus has a first angular period P1 equal to 360 ° / N1. The magnetic escapement 12 further comprises a second magnetic structure 8 defining a second circular array 9 having a second integer number N2, different from the number N1, (N2 = 21 in the example shown) of lines 10 made of magnetic material separated by lines 11 defined by vacuum or a substantially non-magnetic material. This second circular network thus has a second angular period P2 equal to 360 ° / N2. In the particular variant shown, the lines 4 extend substantially over half of the first angular period P1 and the lines 10 extend substantially over half of the second angular period P2. Magnetic material comprises a material with high magnetic permeability, in particular a ferromagnetic material.

The difference in absolute value | ΔN | between the numbers N1 and N2 is here equal to (| AN | = 1). In general, it is expected that the difference in absolute value | ΔN | between the numbers N1 and N2 is less than or equal to N / 2, ie | ΔN | <= N / 2, where N is the lower number of the numbers N1 and N2. In a preferred variant, the number | ΔN | is less than or equal to N / 3 or | ΔN | <= N / 3.

The first and second circular arrays are mounted in parallel at a relatively short distance from one another. They are arranged in such a way that, when the watch movement is operating, the first network has a rotation relative to the second network, around the axis of rotation 6 of the escape wheel, at a first angular frequency F1. In the example given, the second magnetic structure is fixed relative to the watch movement so that the frequency F1 is that of the first circular network in the watch movement (defining a fixed reference). The first and second circular arrays generate in an annular surface (thus having a non-zero radial range), in projection in a geometric plane parallel to these circular arrays, a combined pattern 14 defining a first zone 15 with a high proportion of magnetic surface and a second zone 16 with a lower proportion of magnetic surface. What is remarkable is that the combined pattern 14 rotates with a second angular frequency F2 which is in absolute value N1 times greater than the first angular frequency F1 for the particular case of the given example where the number | ΔN | = 1. Thus, with a first circular network 3 having twenty lines, as shown in FIG. Figure 1 the combined pattern rotates twenty times faster than this grating 3. It will be noted that the magnetic surface density in the combined pattern varies substantially linearly between 50% and 100%. Magnetic surface proportion is understood to mean the ratio of the areas defined by the magnetic material of the first and second circular arrays in a given area of the combined pattern to the total area of that area.

By analogy with the Moire optical effect, the generation of the pattern combined with areas having different proportions of magnetic surface is considered here as a magnetic Moire effect. In general, by providing a difference of lines | ΔN | between the two networks, | ΔN | being the difference in absolute value between the number N1 and the number N2, we obtain alternately a number | ΔN | of first zone (s) with a first proportion of magnetic surface and a number | ΔN | second zone (s) with a second proportion of magnetic area that is smaller than the first proportion. The combined pattern rotates with a second angular frequency F2 equal to the first angular frequency F1 multiplied by the number N1 and divided by the difference ΔN = N1-N2, ie F2 = F1 · N1 / ΔN. In the context of the present invention, the first magnetic structure forms an escape wheel. It will be noted that the number ΔN can be positive or negative. In the case where it is positive, the combined pattern rotates in the same direction as the escape wheel. In the case where the number ΔN is negative, the combined pattern rotates in the opposite direction to that of the escape wheel; which corresponds mathematically to a negative frequency. The magnetic escapement 12 further comprises at least one magnet fixed to the resonator and coupled to the first and second circular networks, as will be discussed later.

To the Figure 2 a magnetic escapement 24 according to a second embodiment is partially shown. The first circular network 3 is similar to that of the Figure 1 but it extends over a greater radial distance. The second magnetic structure 18 forms two concentric circular arrays 19 and 20 which extend into respective contiguous annular surfaces. These two networks have the same number N2 of magnetic lines 21 and 22, separated by lines defined by vacuum or a substantially amagnetic material, and therefore have the same period P2. They are angularly offset by half a period P2 / 2 and thus have a phase shift of 180 °. In this example, N2 = N1 + 2. By superimposing the two magnetic structures 2 and 18, a first combined pattern 25 which extends in an outer annular surface and a second combined pattern 26 which extends into an inner annular surface is obtained in projection in a parallel geometrical plane. . These two combined patterns are contiguous and rotate together at the second angular frequency F2, F2 = (F1 · N1) / (-2). As the number | ΔN | = 2, each combined pattern alternately has two areas with a high proportion of magnetic area and two areas with a smaller proportion of magnetic area.

Given the phase shift between circular arrays 19 and 20, the two combined patterns 24 and 26 also have a phase shift of 180 °. In general, the alternation of zones with a high proportion of magnetic surface and zones with a smaller proportion of magnetic surface defines a periodic combined pattern having an angular period P3 whose value is equal to 360 ° divided by the absolute value of the difference | ΔN | between the numbers N1 and N2, ie P3 = 360 ° / | ΔN |. In the example of the Figure 2 the two combined patterns 25 and 26 each have a period P3 = 360 ° / 2 = 180 °. It will be noted that the realization of figure 2 is a special case with a single circular network on the escape wheel which extends in an annular surface corresponding to the two concentric annular surfaces of the two circular arrays of the second magnetic structure. In a variant, the first magnetic structure also comprises two distinct circular arrays of the same period P1. For example, these two circular arrays have an angular offset of P1 / 4 and the two circular arrays of the second magnetic structure have an angular offset of P2 / 4. It will also be noted that, in a variant, the two circular arrays of the first magnetic structure have different periods P1 and P2 and also those of the second magnetic structure, by inverting the periods P1 and P2 between the two magnetic structures.

As shown in Figures 3A and 3B , the magnetic escapement 24 comprises at least one magnet 32 mounted on the resonator and magnetically coupled to the two superimposed magnetic structures so that, when the mechanical clockwork movement is operating, this magnet has a periodic resonance movement at a resonance frequency. According to the invention, the magnet in magnetic interaction with the two magnetic structures undergoes a movement which is associated with the resulting combined pattern, which can rotate much faster than the escape wheel. To the Figures 3A and 3B is partially shown in section the magnetic interaction of a magnet 32 with the two circular networks 3 and 19 of the Figure 2 . The magnet has a magnetization axis perpendicular to the geometric surface of the combined pattern. To the Figure 3A the magnet is located above a first zone of the combined pattern having a high proportion of magnetic surface. In this first zone, the two arrays are angularly offset so that together they form a relatively continuous magnetic path for the field lines 34A of the magnet; which has the effect of reducing the magnetic reluctance for the magnet. To the Figure 3B the magnet is located above a second area of the combined pattern having a smaller proportion of area magnetic. In this second zone, the two networks are substantially superimposed so that the magnetic path for the magnet in these networks is interrupted by the voids or formed of a non-magnetic material provided between the magnetic lines. It is understood that the field lines 34B of the magnet at the two networks must pass through the void spaces or non-magnetic regions. Magnetic reluctance is therefore increased relative to the situation of the Figure 3A . As a result of this variation of magnetic reluctance, a variation of the magnetic potential energy E _pot which is shown by the graph 36 to the Figure 3C . This variation of the potential magnetic energy E _pot generates a force on the magnet to drive it in rotation and / or to maintain a resonance movement using two concentric annular magnetic tracks.

To the Figure 4 is represented a first embodiment of a regulator device 40 according to a first type. This regulating device comprises a magnetic escapement 24 as described in FIG. Figure 2 . The two superimposed magnetic structures 2 and 18 generate two periodic combined patterns 25 and 26, 180 ° out of phase, as indicated above. The resonator 42 is formed by a tuning fork with two branches 43 and 44. At the free ends of these two branches are respectively fixed two magnets 46 and 48 with axial magnetization. In their rest position, the centers of the two magnets are located on a circle 50, defining a circle of zero position. This circle 50 is chosen so that it is coincident with the circle separating the two contiguous combined patterns. Similar to the devices mentioned in the technological background, the two combined patterns form two magnetic tracks with a periodic variation of the potential energy of the oscillator, formed of the tuning fork 42 and the magnetic escapement. Each magnet oscillates with a substantially radial degree of freedom. It is attracted alternately by the areas of low magnetic reluctance of the two magnetic tracks. Above each track, the magnets accumulate magnetic potential energy and brake the escape wheel. By crossing the zero position circle, they each receive a pulse serving to maintain the resonance since they experience a magnetic potential jump by virtue of the angular offset of the two periodic combined patterns 25 and 26. Thus, in a rotating frame linked to the escape wheel, the magnets follow a trajectory 50 corresponding to an oscillation according to the degree of freedom of each magnet.

Concerning the reduction ratio between the oscillation frequency F _osc of the tuning fork and the rotation frequency F1 of the escapement wheel carrying the first magnetic structure (in the case where the second magnetic structure does not rotate), it is necessary to on the one hand the rotation frequency F2 of the combined units 25 and 26 which is equal to F1 · N1 / ΔN (ΔN being the difference between N1 and N2). On the other hand, the oscillation frequency F _osc is equal to F2 · AN. This gives a relationship F _OSC = F2 = F1 · · .DELTA.N N1 regardless .DELTA.N. Thus, the reduction ratio is independent of the number ΔN. We can take advantage of this fact by selecting ΔN small, in particular | ΔN | = 2 or 4. The invention is remarkable because one can have periodic combined patterns with a relatively large period for a large reduction ratio, and thus allow to use magnets of large dimensions having a relatively large magnetic interaction zone with the magnetic structures defining the combined patterns, without requiring a decrease in the reduction ratio. In order for the magnets of the tuning fork to oscillate symmetrically with respect to the axis of rotation 6, the number ΔN is an even number. To the Figure 4 , ΔN = -2.

To the Figure 5 is represented a second embodiment of a regulator device 60 according to the invention comprising a magnetic escapement 24A formed by a first magnetic structure 2 defining the first circular network 3, this structure 2 being mounted on a shaft and rotating around a axis of rotation 6. The magnetic escapement is furthermore formed by a second magnetic structure 18 defining two out-of-phase circular networks as explained above in relation to the Figures 2 and 4 . This second embodiment differs from the previous embodiment in that the resonant portion 68 of the resonator 70 comprises two magnets 32 and 62 respectively arranged on both sides of the two magnetic structures and forming the magnetic escapement 24A. Such a configuration solves a problem of the first embodiment in that, insofar as the two magnetic structures are substantially equidistant from the respective magnets facing them, the axial attraction forces on the two magnets by the Magnetic structures compensate each other for the most part. It is the same for the attraction forces exerted by the two magnets on the set of two magnetic structures.

The two magnets are attached to the ends of a non-magnetic member having a U shape. The resonator is shown with a schematic spring. The resonant portion 68 may for example be attached to a free end of a tuning fork. The operation is similar to that of the first embodiment. Each magnet is magnetically coupled to the circular arrays in the manner previously described. They are aligned axially so as to both be perpendicular to the zero position circle. The structure 18 is fixed and supported by a disc 66 formed of a non-magnetic material. A lateral recess is provided in this disc to allow the resonant portion 68 to pass under the structure 18. It will be noted that in the variant shown, the magnetic structures 2 and 18 each have an inner annular portion and an outer annular portion which connect the lines of the circular networks 3, 19 and 20.

In the variant shown, the two magnets have an axial magnetization of opposite direction. This configuration is advantageous because it makes it possible to amplify the magnetic interaction as can be seen in FIG. Figure 6 . The first image (Δx = 0) is a section similar to that of the Figure 3B so that the second image (Δx = 0.5-P3) is a cut similar to that of the Figure 3A . In the second image, as the two superimposed circular arrays are substantially screen between the two magnets, the magnetic interaction is in first approximation approximately equal to twice that for the case of a single magnet. On the other hand, in the first image, the two magnets repel each other in the empty spaces between the magnetic lines. This repulsive force increases the magnetic potential energy E _pot. The curve 74 of E _pot has a profile similar to that of curve 36 of the Figure 3C . However, a computer simulation has established that the amplitude of the periodic curve 74 is a priori an order of magnitude greater than the amplitude of the periodic curve 36.

In a variant shown in Figure 7 both magnets have an axial magnetization of the same direction. The lines of the circular networks are provided here thicker. It is observed on the graph of the magnetic potential energy that the curve 76 of E _pot is the opposite of the curve 74. Indeed, since in this variant the magnetic flux between the two magnets is substantially axially channeled, a The area of high magnetic area proportion of a combined pattern has a greater magnetic reluctance for the two magnets than in the case where they face an area of least proportion of magnetic area. The amplitude of the periodic curve 76 is a priori in the configuration represented approximately half of that of the periodic curve 74.

A third embodiment of a regulator device 80 of the first type is shown in FIG. Figure 8 . The common elements with the realization of the Figure 5 will not be described again in detail. The regulator device comprises a resonator 70 and a magnetic escapement 24B formed by a first magnetic structure 2A, defining a first circular network similar to the network 3 of the Figure 2 , and by a second magnetic structure 18A defining two concentric circular networks corresponding to the networks 19 and 20 of the figure 2 . Note that in this case, it is the two concentric circular arrays that form the escape wheel and which rotate around the axis 6, the structure 2A being fixedly mounted in the watch movement. This third embodiment differs essentially from the previous embodiment in that it comprises a third magnetic structure 82 defining a fourth circular network which extends, like the first network, in an annular surface comprising the second and third phase-shifted networks of the structure. 18A. This third structure is integral with the first structure 2A, the fourth circular network being identical to the first circular network and their magnetic lines are superimposed axially (no angular offset between the two networks). The first and fourth networks are respectively located on one side and the other of the magnetic structure 18A forming the second and third networks.

The magnetic structure 18A comprises a central annular portion which is continuous. Between the second and third networks is provided an annular intermediate portion which is continuous, preferably of magnetic material. In addition, there is also provided a continuous annular peripheral portion. The three continuous annular parts allow to have a magnetic structure 18A in one piece with the magnetic lines of the two networks fixed at both ends. So that the continuous annular zones do not disturb the operation of the magnetic escapement, it is expected that the circular arrays extend over a radial length substantially greater than that of the oscillating magnets. This structure 18A is taken in a nonmagnetic hub 86 mounted on the shaft of the escape wheel. The two fixed structures 2A and 82 respectively comprise two continuous annular peripheral parts which are connected by a nonmagnetic spacer 84. This embodiment solves a problem remaining in the second embodiment. Indeed, the two superimposed magnetic structures are attracted to each other because of the magnetic flux of the magnets. Thanks to the superposition of the three magnetic structures, these Most of the attraction forces cancel out if the intermediate magnetic structure is located substantially in the middle of the other two. It will be noted that various variants are conceivable. In a first variant, the two concentric out-of-phase networks are provided in the first and third magnetic structures while the second magnetic structure forms a single extended circular network. In another variant, it is expected that the first and third outer structures are mounted on the shaft of the escape wheel and are integral in rotation, while the second intermediate structure is fixedly mounted in the watch movement.

An alternative embodiment will be briefly described using the Figure 9 . This regulator device 90 is distinguished by the fact that the magnetic escapement 24C comprises two magnetic structures 2B and 82A, located on either side of an escape wheel, which are connected to the watch movement by two non-magnetic supports 94 and 96 central respectively fixed in two bridges 95 and 97, and in that the two intermediate circular networks 19 and 20 are doubled and arranged on both sides of a nonmagnetic disc 92 forming the escape wheel.

A first embodiment of a second device regulating the movement of a watch movement will be described using the Figure 10 . The regulator device 100 comprises a magnetic escapement 12 as described with the aid of FIG. Figure 1 , with the only difference that the superimposed circular networks have more magnetic lines and thus a smaller angular period. However, as in Figure 1 , the difference of magnetic lines | ΔN | is equal to one (| ΔN | = 1). An escape wheel (not shown entirely) carries one of the two magnetic structures forming the combined pattern 14 and rotates about the central axis 6 circular networks defined by these two magnetic structures. The regulator device further comprises a resonator 102 having a resonant portion comprises a magnet 104. This resonator has two degrees of freedom with a resonance mode in which the magnet 104 substantially follows a circular path with an angular frequency of resonance, without turning on itself. For this purpose, this resonator is arranged so that, when the center of the magnet moves away from the axis of rotation 6, its resonant portion is subjected to a radial restoring force relative to the axis of rotation 6, this restoring force is preferably angularly isotropic and radially linear so that the regulating device is isochronous. Thus, the resonator is arranged so that the center of the magnet 104 substantially follows a circular path, centered on the axis of rotation, with an angular frequency of resonance F _res when it is distant from this axis of rotation and that this magnet is rotated with a substantially constant torque. It should be noted that the trajectory can also be elliptical in this system without harming isochronism. In the latter case, it will be ensured that the magnet remains at least partially superimposed on the combined pattern formed by the superimposed circular magnetic gratings. Such a resonator is shown schematically in the Figure 10 by a magnet 104 connected to two springs 106 and 108 which are orthogonal and which have substantially the same coefficient of elasticity, these two springs being respectively mounted on the supports 110 and 112 which slip without friction respectively in two orthogonal rails 114 and 116; which is schematized by trolleys on wheels which theoretically have no inertia. The vector sum of the radial forces of the springs generates a restoring force (centripetal force) allowing the inertial portion of the resonator to follow a substantially circular or elliptical trajectory.

Then, the annular region of the first and second magnetic structures, defining the combined pattern 14 with a first area 15 having a high proportion of magnetic area and a second area 16 having a smaller proportion of magnetic area, is magnetically coupled to the magnet 104 so that this magnet is rotated by a magnetic interaction couple resulting from the combined pattern rotating at angular frequency ω. The combined pattern rotates when a torque motor, a useful range of the engine torque is supplied to the escapement wheel, the angular frequency ω of the combined pattern being slaved to the angular resonance frequency F _res in this useful range of the torque , the latter being selected so that the aforementioned magnetic interaction torque remains below a maximum magnetic interaction torque and said circle described by said center of the magnet has a radius comprised in the radial range of the combined pattern 14 for any motor torque of this useful range. The magnetic interaction in this resonator has the effect of synchronizing the angular frequency ω of the escape wheel with the resonance frequency F _res of the resonator. The combined pattern 14 generates a variation of the potential energy E _pot in the resonator, as a function of the relative angular position of the magnet and this combined pattern, between a minimum energy when the magnet is above the first zone 15 and a maximum energy when it is above the second zone 16. The angular gradient of this potential energy generates a tangential driving force on the magnet. To avoid a loss of synchronization, it will be ensured that the braking torque exerted by the magnet on the escape wheel remains less than the maximum magnetic interaction torque depending on the maximum value of the potential energy gradient E _pot .

In a preferred variant, the resonator is arranged and the useful range of the selected motor torque so that the magnet 104 is entirely superimposed on the combined pattern 14 for any motor torque of this useful range.

The Figure 11 shows an alternative embodiment of the regulating device of the Figure 10 . The elements already described above will not be again. This variant is distinguished from the previous one by the fact that the magnetic escapement 24A is formed by two superimposed circular arrays with a difference in absolute value | ΔN | between their numbers respective magnetic lines equal to two, ie | ΔN | = 2, similarly to the realization of one of the two combined patterns of the Figure 2 . Thus, the combined pattern 25A alternately has two areas 15A having a high proportion of magnetic area and two areas 16A having a smaller proportion of magnetic area. Since the difference in magnetic potential energy between the extreme values is substantially equal to that of the preceding variant, but this difference occurs over an angular range that is twice as small, the maximum magnetic magnetic interaction force is substantially twice stronger. On the other hand, the ratio between the angular frequency of the combined pattern 25A and the rotation frequency of the escapement wheel carrying one of the two circular magnetic gratings is equal to half of the ratio of the preceding variant. Thus, the useful range of the engine torque is increased but the multiplication ratio between the frequency of the escape wheel and the resonance frequency is decreased. It will be noted that the magnet 104 has an angular offset α less than 90 ° and in particular less than 45 °, this angular displacement varying as a function of the torque resulting from the magnetic interaction between the magnet 104 and the combined pattern 25A.

The Figure 12 schematically represents a second embodiment of the second regulator device according to the invention. This regulator device 130 is a particular embodiment implementing the physical characteristics mentioned in the preceding description of the first embodiment. The resonator 132 is formed by a bar 134 elastically deformable in two degrees of freedom substantially defining a sphere portion, this bar being embedded in a base 136. This bar carries at its free end a magnet 104A. The magnetic exhaust 12A is similar to that described in Figures 2 and 10 . It comprises a first magnetic structure 2A, forming a first circular network 3A whose magnetic lines 4A extend in a first frustoconical surface, and a second magnetic structure 8A, forming a second circular network 9A whose magnetic lines 10A extend in a second frustoconical surface parallel to the first frustoconical surface. There is obtained as already described a combined pattern 14A similar to the combined pattern 14 mentioned above. The first magnetic structure 2A is mounted on a shaft 138 which is guided in rotation by two ball bearings arranged in a bridge 142. The second magnetic structure is fixed and arranged on a non-magnetic support 146. The structure 2A comprises a continuous inner annular portion which connects the magnetic lines 4A and the structure 8A comprises a continuous outer annular portion which connects the magnetic lines 10A. At one end of the shaft 138 is provided a frustoconical portion 140 forming a central circular stop for the magnet 104A, this stop being arranged so that at least the major part of this magnet remains superimposed on the combined pattern 14A when no torque engine is provided to the escape wheel formed here by the first magnetic structure 2A, the shaft 138 and a pinion 144. This pinion is associated with a counting gear of a mechanical watch movement through which it receives a motor torque provided by a motor device (not shown).

Finally, in general, the invention relates to a mechanical clockwork comprising a regulating device, a counter wheel clocked by this regulating device and a motor device driving the counter wheel and maintaining a resonance mode of the regulating device. This watch movement is characterized in that it comprises a magnetic escapement according to the invention or a regulating device according to the invention.

Claims (22)

Magnetic escapement equipping a mechanical horological movement and comprising an escape wheel driven by a motor device and associated with a resonator of this mechanical clock movement, this escape wheel comprising a first magnetic structure defining, in a non-zero radial range of this escape wheel, a first periodic pattern with a first angular period P1 such that 360 ° / P1 is equal to a first integer number N1, the magnetic escapement comprising at least one magnet mounted on the resonator and magnetically coupled to the impeller; such that, when the mechanical clockwork movement operates, this magnet has a periodic resonance movement at a resonance frequency and the escape wheel rotates with a frequency proportional to this resonance frequency; characterized in that the magnetic escapement comprises a second magnetic structure parallel to the first magnetic structure and defining, in said radial range, a second periodic pattern having a second angular period P2 such that 360 ° / P2 is equal to a second integer N2 different from the integer N1, the difference in absolute value | ΔN | between the numbers N1 and N2 being a number less than or equal to N / 2, ie | ΔN | <= N / 2, where N is the lower number of the numbers N1 and N2; in that the first and second magnetic structures are arranged such that, when the watch movement is operating, the first magnetic structure rotates relative to the second magnetic structure at a first relative angular frequency F1 _rel ; and in that the first periodic pattern and the second periodic pattern are selected so that they generate in said radial range, in projection on a geometric surface parallel to the first and second magnetic structures, a combined pattern alternately defining at least said number | ΔN | of first zone (s) with a first proportion of magnetic surface and at least this number | ΔN | second zone (s) with a second proportion of magnetic area that is smaller than said first proportion, and that the combined pattern rotates relative to the second magnetic structure with a second relative angular frequency F2 _rel equal to said first angular frequency _rel relative F1 multiplied by said number N1 and divided by the difference .DELTA.N between the numbers N1 and N2, or F2 = F1 _{rei rel} · N1 / .DELTA.N where .DELTA.N = N 1-N2. Magnetic escapement of claim 1, characterized in that said magnet has a magnetization axis perpendicular to said surface of said combined geometric pattern. Magnetic escapement according to claim 1 or 2, characterized in that said combined pattern defines a periodic combined pattern alternately having said number | ΔN | of first zone (s) and this number | ΔN | second zone (s), any first zone and a second adjacent zone defining an angular period P3 of this periodic combined pattern whose value is equal to 360 ° divided by the number | ΔN |; let P3 = 360 ° / | ΔN |. Magnetic escapement according to claim 3, characterized in that said first pattern forms a first circular network with lines of magnetic material separated by lines defined by vacuum or a substantially non-magnetic material, and said second pattern forms a second circular network also with lines of magnetic material separated by lines defined by vacuum or a substantially non-magnetic material. Magnetic escapement of claim 4, characterized in that said lines of magnetic material of said first circular array extend substantially half said first angular period P1 and said lines of said second magnetic material circular network extend substantially over half of said second angular period P2. Device for regulating the movement of a clockwork movement comprising a magnetic escapement according to any one of Claims 3 to 5, characterized in that it comprises a resonator whose resonant part supporting said magnet undergoes, during operation of the watch movement, an oscillation according to a degree of freedom; in that the resonator is arranged so that the center of said magnet in its rest position is substantially located, for any angular position of the escape wheel, on a zero position circle which is centered on the axis of rotation of the escape wheel and which is traversed by said degree of freedom of said resonant portion of the resonator; and in that said periodic combined pattern is located on a first side of the zero position circle projected perpendicularly into said geometric surface, the annular region of the first and second magnetic structures, defined by said radial range, being magnetically coupled to said magnet in a first alternation of each period of said oscillation so that, for each period of this oscillation, the periodic combined pattern rotates by an angular distance equal to its angular period P3. A regulator device according to claim 6, said periodic combined pattern being a first periodic combined pattern and said radial range being a first radial range; characterized in that the first and second magnetic structures respectively define, in a second non-zero radial range of the escape wheel located on the other side of said zero position circle with respect to the first radial range, a third periodic pattern and a fourth periodic pattern which generate a second periodic combined pattern alternately having said number | ΔN | third zone (s), with a third proportion of magnetic area greater than said second proportion, and this number | ΔN | fourth zone (s) with a fourth proportion magnetic surface which is smaller than the first and third proportions, this second periodic combined pattern having said angular period P3; and in that the second periodic combined pattern is angularly offset by one half of an angular period P3 relative to the first periodic combined pattern, this second periodic combined pattern also rotating with said second relative angular frequency F2 _rel , the annular region of the first and second magnetic structures, defined by said second radial range, being magnetically coupled to said magnet in a second alternation of each period of said oscillation. A regulating device according to claim 7 dependent on claim 4, characterized in that said third periodic pattern forms a third circular array with lines of magnetic material separated by lines defined by vacuum or a substantially non-magnetic material, and said fourth periodic pattern forms a fourth circular network also with lines of magnetic material separated by lines defined by vacuum or a substantially non-magnetic material, the third and fourth circular arrays having an angular period respectively equal to the first and second angular periods P1 and P2. Regulator device according to claim 8, characterized in that said first and second periodic combined patterns are substantially contiguous; and in that the first and third circular arrays or the second and fourth circular arrays together form the same circular array which extends at least over the first and second radial arrays. Regulator device according to any one of claims 7 to 9, characterized in that said resonator is formed by a tuning fork with two branches, said magnet forming a first magnet fixed to the free end of a first branch, this resonator comprising in besides second magnet attached to the free end of the second leg; and that the number | .DELTA.N | is an even number. Regulator device according to Claim 10, characterized in that the number | ΔN | is equal to two, ie | ΔN | = 2. Device for regulating the movement of a watch movement comprising a magnetic escapement according to any one of claims 1 to 5, characterized in that it comprises a resonator having a resonant part supporting said magnet, this resonator being arranged so that this resonant part is subjected to a radial restoring force relative to the axis of rotation of the escape wheel when the center of the magnet moves away from this axis of rotation, and so that the center of this magnet substantially follows a circular or elliptical trajectory, centered on said axis of rotation, at an angular frequency of resonance when it is distant from this axis of rotation and that this magnet is rotated with a substantially constant torque; and in that the annular region of said first and second magnetic structures, defined by said radial range, is magnetically coupled to said magnet such that said magnet is rotated by a magnetic interaction torque resulting from said combined rotating pattern when a pair motor, in a useful range of the motor torque, is provided to said escape wheel, the angular frequency of the combined pattern being slaved to said angular resonance frequency in this useful torque range, which is selected such that said torque of magnetic interaction remains below a maximum magnetic interaction torque and that said path of the center of said magnet has a radius included in said radial range for any motor torque of this useful range. Regulator device according to claim 12, characterized in that the resonator is arranged and said useful range of the motor torque selected so that said magnet is entirely superimposed on said combined pattern for any motor torque of this useful range. Regulator device according to claim 12 or 13, characterized in that said number | ΔN | is equal to one or two, ie | ΔN | = 1 or | ΔN | = 2. Regulator device according to any one of claims 12 to 14, characterized in that it comprises a central circular stop for said magnet, this stop being arranged so that at least the major part of this magnet remains superimposed on said combined pattern when no driving torque is provided to said escape wheel. Regulator device according to any one of claims 6 to 15, said magnet being a first magnet; characterized in that said magnetic escapement comprises a second magnet mounted on said resonator and supported by said resonant portion or by another resonant portion of the resonator, said second magnet being arranged relative to the first magnet on the other side of the first and second magnetic structures , so that it is aligned with the first magnet in a direction substantially parallel to said axis of rotation and has a periodic resonance movement similar to that of the first magnet at said resonant frequency. Regulator device according to claim 16, characterized in that the second magnet has a magnetization axis parallel to that of the first magnet and in the opposite direction. Regulator device according to claim 16, characterized in that the second magnet has a magnetization axis parallel to that of the first magnet and in the same direction. Regulator device according to any one of claims 16 to 18, characterized in that said magnetic escapement comprises a third magnetic structure defining a periodic pattern substantially identical to the periodic pattern defined by the first or second magnetic structure and superimposed thereto, this third periodic structure being integral in rotation with this first or second magnetic structure, in the case where the latter undergoes a rotation, the two magnetic structures having the same periodic pattern being respectively on one side and the other side of the magnetic structure having a different periodic pattern. Device regulating the movement of a watch movement according to any one of claims 6 to 19, characterized in that said second magnetic structure is fixed relative to the watch movement, said first relative angular frequency F1 _rel defining the angular frequency of said wheel exhaust relative to this watch movement. Mechanical clock movement comprising a regulating device, a counter wheel clocked by this regulating device and a motor device driving the counter wheel and maintaining a resonance mode of the regulating device, characterized in that this regulating device comprises a magnetic escapement according to any one Claims 1 to 5 Mechanical clock movement comprising a regulating device, a counter wheel clocked by this regulating device and a motor device driving the counter wheel and maintaining a resonance mode of the regulating device, characterized in that said regulating device is a regulating device according to any one Claims 6 to 20.

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