HK1233723B - Magnetic timepiece escapement and regulator device for the operation of a timepiece movement - Google Patents

Description

Magnetic watch escapement and device for regulating the operation of a watch movement

Technical Field

The present invention relates to the field of devices for regulating the operation of timepiece movements. In particular, it relates to a timepiece escapement of the magnetic type, the general functions of which are to maintain the resonant mode of a resonator, in particular the continuous oscillation or rotation of the inertial part of this resonator, and to count the speed of the mechanism. Within the scope of the invention, a magnetic escapement ensures these two functions by means of an escape wheel comprising a magnetic structure that is magnetically coupled to at least one magnet carried by the part of the resonator that moves in resonant motion.

Background Art

Devices for regulating the speed of a wheel, also known as a rotor, by means of a magnetic coupling, also known as a flux linkage, have been known for many years. Horological applications are also known. Horstmann Clifford Magnetics has filed numerous patent applications related to this field, alleging C.F. Clifford's invention. Reference is made in particular to documents FR 1,113,932 and US 2,946,183. A magnetic escapement of the same type is also known from Japanese Utility Model No. JPS 5263453U (application No. JP19750149018U), which features a direct magnetic coupling between a resonator and an escape wheel formed by a disk supporting two coaxial annular magnetic tracks. These two tracks are essentially continuous and each comprises magnetic zones formed by separate plates of a high-permeability magnetic material, regularly arranged with a given angular period, the plates of the first track being offset or phase-shifted by half a period relative to the plates of the second track. A non-magnetic zone, i.e., a zone of poor magnetic permeability, is provided between the plates. Thus, high-permeability magnetic zones are obtained, which are alternately distributed on either side of a circle corresponding to the inoperative position (zero position) of at least one magnet carried by the end of one branch of the tuning-fork resonator. The magnet of the resonator is magnetically coupled to the two phase-shifted tracks so that it is alternately attracted by the magnetic zones of the first and second tracks. The escape wheel thus rotates at a rotational speed such that it advances by one angular period of the two tracks with each oscillation of the resonator. The escape wheel provides the energy required to maintain the oscillation of the branch of the resonator carrying the magnet of the magnetic coupler, and the resonator controls or regulates the rotational speed of the escape wheel, which is proportional to the resonant frequency. Thus, there is a magnetic escapement mechanism connected to the resonator, which together form a device for regulating the operation of the counting mechanism of a timepiece movement.

It should be noted that the regulating device of the magnetic type described above is provided in the prior art for a resonator having a single degree of freedom for each part in which the resonant motion occurs. Generally speaking, the resonator is designed so that the magnet carried by the element in which the resonant motion occurs oscillates according to a substantially radial direction, that is to say approximately orthogonal to the two annular magnetic tracks. In this case, the embodiments of the prior art described above have the advantage of downconversion (i.e., frequency reduction) between the oscillation frequency of the resonator and the rotation frequency (in revolutions/s) of the escape wheel carrying the magnetic structure. The mobile body, which is not pivoted, rotates 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 of the frequency reduction between the resonator's oscillations and the escape wheel's rotation results in a problem of magnetic coupling forces. In fact, in order to increase the frequency reduction, it is necessary to increase the number of periods of the magnetic track. For a given diameter of the escape wheel, this increase in the number of periods results in a reduction in the surface area of the magnetic area of the annular track. Since the resonator's magnets extend over an angular distance that is less than half a period of the annular track, the size of these magnets must also be reduced when the frequency reduction increases. It is therefore understood that the magnetic interaction forces between the resonator and the escape wheel decrease; this 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" is understood here to mean a defined proportional relationship between the resonant frequency and the frequency of rotation of the escape wheel.

Finally, it should be pointed out that a horological regulating device of the magnetic type comprising a resonator with two degrees of freedom, in particular a resonator whose inertial portion has a substantially circular translation path due to continuous rotation in the same direction, is not known. However, there is a need in the horological field to design a magnetic type escapement for such a resonator with two degrees of freedom, in which the level of magnetic coupling is reduced. This need even appears to be crucial when the resonator operates at a relatively high resonant frequency, for example when the resonant element of the resonator rotates at a frequency greater than 10 revolutions per second (10 revolutions per second = 10 Hz). In fact, the mechanical coupling involved in connecting such a resonant element to the mobile body will result in setting the mobile body in rotation at the resonant frequency. The main problems with pivoted mobile bodies with a rotation frequency greater than 5 or 6 revolutions per second are energy losses due to friction and wear problems at the bearing locations.

Summary of the Invention

The object of the present invention is to meet certain requirements in the field of timepiece regulating devices, in particular for resonators with two degrees of freedom for circular resonant movements, and to find a solution to the problems associated with weak magnetic interactions in the case of resonators with a single degree of freedom connected to known magnetic escapements with a significantly reduced frequency.

To this end, the subject of the invention is a magnetic escapement mechanism intended to equip a mechanical timepiece movement and comprising an escape wheel driven by a motor device and coupled to a resonator of the mechanical timepiece movement, the escape wheel comprising a first magnetic structure defining, within a non-zero radial extent of the escape wheel, a first periodic pattern having a first angular period P1, such that 360°/P1 is equal to a first integer N1, the magnetic escapement mechanism comprising at least one magnet mounted on the resonator and magnetically coupled to the escape wheel, such that, when the mechanical timepiece movement is operating, the magnet exhibits a periodic resonant motion at a certain resonant frequency and causes the escape wheel to rotate at a frequency proportional to this resonant frequency. The magnetic escapement mechanism further includes a second magnetic structure, parallel to the first magnetic structure, and defining a second periodic pattern having a second angular period P2 within the radial range, such that 360°/P2 is equal to a second integer N2 different from the integer N1, and the absolute value of the difference between the integers N1 and N2, |ΔN|, is a number less than or equal to N/2, i.e., |ΔN|<=N/2, where N is the smaller of the integers N1 and N2. The first and second magnetic structures are designed such that, when the timepiece movement is in operation, 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: within the radial range, the first periodic pattern and the second periodic pattern produce a combined pattern in their projections onto a geometric surface parallel to the first and second magnetic structures, the combined pattern is coupled to the magnet and alternately defines at least the number |ΔN| first regions comprising a first proportion of magnetic surfaces and at least the number |ΔN| second regions comprising a second proportion of magnetic surfaces smaller than the first proportion, and so that the combined pattern rotates relative to the second magnetic structure at a second relative angular frequency F2 _rel , the second relative angular frequency being equal to the first relative angular frequency F1 _rel multiplied by the integer N1 and divided by the difference ΔN between the integers N1 and N2, i.e., F2 _rel =F1 _rel ·N1/ΔN, where ΔN=N1–N2.

The angular frequency is understood to be the number of revolutions per second corresponding to the inverse of the temporal period of the periodic motion.

In a preferred variant, the magnets have a magnetization axis perpendicular to the geometrical surface of the combined pattern.

In a preferred embodiment, the combination pattern defines a periodic combination pattern, which alternately has the number |ΔN| first areas and the number |ΔN| second areas, and any first area and an adjacent second area define an angular period P3 of the periodic combination pattern, and the value of P3 is equal to 360° divided by the number |ΔN|, that is, P3 = 360°/|ΔN|.

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

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

In an advantageous variation of the improved embodiment, the magnetic escapement mechanism includes a third magnetic structure defining a periodic pattern substantially identical to and superimposed on the periodic pattern defined by the first or second magnetic structure, the third magnetic structure rotating integrally with the first or second magnetic structure when the first or second magnetic structure rotates. Two magnetic structures having the same periodic pattern are located on either side of a magnetic structure having a different periodic pattern.

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

The invention also relates to a first device for regulating the operation of a timepiece movement, comprising a magnetic escapement according to the invention and a resonator, a resonant portion of the resonator supporting the magnet oscillating according to one degree of freedom during the operation of the timepiece movement. The resonator is designed so that, for any angular position of the escape wheel, in its rest position, the center of the magnet lies substantially on a zero position circle, centered on the axis of rotation of the escape wheel and intersected by the degree of freedom of the resonant portion of the resonator. The periodic composite pattern defined by the magnetic escapement is located on a first side of the zero position circle, projected perpendicularly in the geometrical surface, the annular areas of the first and second magnetic structures defined by the radial extent being magnetically coupled to the magnet during the first alternation of each period of the oscillation, so that, for each period of the oscillation, the periodic composite pattern rotates by an angular distance equal to its angular period P3.

In a preferred embodiment of the first regulating/speed regulating device, the periodic combined pattern is a first periodic combined pattern and the radial range is a first radial range. Within a second non-zero radial range of the escape wheel located on the other side of the null circle relative to the first radial range, the first and second magnetic structures respectively define a third periodic pattern and a fourth periodic pattern that produce a second periodic combined pattern. The second periodic combined pattern alternately comprises the number |ΔN| third regions and the number |ΔN| fourth regions, the third regions comprising a third ratio of magnetic surface that is greater than the second ratio, and the fourth regions comprising a fourth ratio of magnetic surface that is less than the first and third ratios. The second periodic combined pattern has the angular period P3. The second periodic combined pattern is angularly offset relative to the first periodic combined pattern by half the angular period P3. The second periodic combined pattern also rotates at the relative angular frequency F2 _rel of the first periodic combined pattern. The annular regions of the first and second magnetic structures defined by the second radial range are magnetically coupled to the magnet during the second alternation of each cycle of the oscillation.

In one particular variation, the first and second periodic combined patterns are substantially continuous.

The present invention also relates to a second device for regulating the operation of a watch movement, the watch movement comprising a magnetic escapement according to the invention and a resonator having a resonant portion supporting the magnet, the resonator being designed so that when the center of the magnet moves away from the axis of rotation of the escape wheel, the resonant portion is subjected to a radial reset force relative to the axis of rotation, and so that when the center of the magnet moves away from the axis of rotation, the center of the magnet substantially defines a circle centered on the axis of rotation at a certain angular resonant frequency, and so that the magnet is set to rotate with a substantially constant torque. The annular areas of the first and second magnetic structures defined by the radial range are magnetically coupled to the magnet so that the magnet is set to rotate by a magnetic interaction torque, the magnetic interaction torque being derived from the combined pattern that rotates when a driving torque within an available range of driving torque is supplied to the escape wheel, the angular frequency of the combined pattern being controlled at the angular resonant frequency within the available range of torque, the available range of torque being selected so that the magnetic interaction torque remains below a maximum magnetic interaction torque and so that for any driving torque within the available range, the circle defined by the center of the magnet has a radius within the radial range.

In a preferred variant, the resonator is designed and the usable range of drive torques is selected such that for any drive torque within the usable range, the magnets are completely superimposed on the combined pattern.

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

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below with the aid of the accompanying drawings, given as examples and in a non-limiting manner, in which:

FIG. 1 schematically shows in plan view two magnetic structures in a first embodiment of a magnetic escapement according to the invention and their superposition in order to form this first embodiment;

FIG. 2 schematically shows in plan view two magnetic structures in a second embodiment of a magnetic escapement according to the invention and their superposition in order to form this second embodiment;

3A and 3B show, in partial cross-section, a magnetic escapement according to the invention, respectively in a first position of its magnet and in a second position of the magnet;

- FIG. 3C shows a schematic graph of the variation in magnetic potential energy of the magnetic escapement shown in FIGS. 3A and 3B ;

- FIG. 4 schematically shows a first embodiment of a first adjustment device according to the invention;

- FIG5 schematically shows a second embodiment of the first adjustment device according to the invention in a sectional view;

- FIG6 shows two partial cross-sectional views and a graph relating to a third embodiment of a magnetic escapement according to the invention, which are similar to FIGS. 3A , 3B and 3C respectively;

- FIG7 shows two partial cross-sectional views and a graph respectively similar to FIGS. 3A , 3B and 3C , relating to a fourth embodiment of a magnetic escapement according to the invention;

- FIG8 schematically shows a third embodiment of the first adjustment device according to the invention in a sectional view;

- FIG. 9 schematically shows an embodiment variant of the adjustment device of FIG. 8 ;

- FIG10 schematically shows a plan view of a first embodiment of a second adjustment device according to the invention;

- FIG. 11 schematically shows an embodiment variant of the adjustment device of FIG. 10 ; and

- Figure 12 shows schematically in cross section a second embodiment of a second adjustment device according to the invention.

DETAILED DESCRIPTION

FIG1 partially illustrates the structure of a first embodiment of a magnetic escapement 12 equipped with a mechanical timepiece movement and including an escape wheel formed by a first magnetic structure 2 defining a first circular network 3 in an annular surface, comprising a first integer N1 (in the example shown, N1=20) of threads 4 made of magnetic material, separated by threads 5 defined by spaces or a substantially non-magnetic material. This first circular network thus has a first angular period P1 equal to 360°/N1. Magnetic escapement 12 also comprises a second magnetic structure 8 defining a second circular network 9 comprising a second integer N2 (in the example shown, N2=21) of threads 10 made of magnetic material, separated by threads 11 defined by spaces 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 line 4 extends approximately over half of the first angular period P1 and the line 10 extends approximately over half of the second angular period P2. Magnetic material is understood to be a material having a high magnetic permeability, in particular a ferromagnetic material.

Here, the absolute value of the difference between numbers N1 and N2, |ΔN|, is equal to 1 (|ΔN|=1). Generally speaking, the absolute value of the difference between numbers N1 and N2, |ΔN|, is specified to be less than or equal to N/2, i.e., |ΔN|<=N/2, where N is the smaller of numbers N1 and N2. In a preferred embodiment, the absolute value of the difference between numbers N1 and N2, |ΔN|, is specified to be less than or equal to N/3, i.e., |ΔN|<=N/3.

The first and second circular networks are mounted parallel to each other with a small spacing. They are designed so that, when the watch movement is operating, the first network rotates relative to the second network at a first angular frequency F1 about the axis of rotation 6 of the escape wheel. In this given example, the second magnetic structure is fixed relative to the watch movement so that the frequency F1 is the frequency of the first circular network in the watch movement (defining a fixed reference). The first and second circular networks, in a toroidal surface (thus having a non-zero radial extent), produce, in projection onto a geometric plane parallel to these circular networks, a composite pattern 14 that defines a first region 15 containing a large proportion of magnetic surface and a second region 16 containing a smaller proportion of magnetic surface. Composite pattern 14 is magnetically coupled to the resonator's magnet (not shown). In particular, composite pattern 14 rotates at a second angular frequency F2, which, for the specific case of the given example where the number |ΔN|=1, has an absolute value N1 times that of the first angular frequency F1. Thus, for a first circular network 3 with 20 lines, as shown in FIG1 , this composite pattern is 20 times the rotation speed of this network 3. It should be noted that the density of the magnetic surface in the combined pattern varies approximately linearly between 50% and 100%. The proportion of the magnetic surface is understood to be the ratio between the surface area defined by the magnetic material of the first and second circular networks in a given area of the combined pattern and the total surface area of that area.

Similar to the optical moiré effect, the generation of a combined pattern with regions containing magnetic surfaces of varying proportions is considered a magnetic moiré effect. Generally speaking, by setting the line difference |ΔN| between the two networks (|ΔN| is the absolute value of the difference between the numbers N1 and N2), a certain number |ΔN| of first regions containing a first proportion of magnetic surfaces is alternately obtained, with a certain number |ΔN| of second regions containing a second proportion of magnetic surfaces smaller than the first proportion. The combined pattern rotates at a second angular frequency F2, which is equal to the first angular frequency F1 multiplied by the number N1 and divided by the difference ΔN=N1-N2, i.e., F2=F1·N1/ΔN. Within the scope of the present invention, the first magnetic structure forms an escape wheel. It should be noted that the number ΔN can be positive or negative. If it is positive, the combined pattern rotates in the same direction as the escape wheel. If the number ΔN is negative, the combined pattern rotates in the opposite direction to the escape wheel; this mathematically corresponds to a negative frequency. The magnetic escapement 12 also comprises at least one magnet fixed to the resonator and coupled to the first and second circular networks, as will be explained later.

FIG2 partially illustrates a magnetic escapement 24 according to a second embodiment. The first circular network 3 is similar to the first circular network of FIG1 , but extends over a greater radial distance. The second magnetic structure 18 forms two concentric circular networks 19 and 20, which extend into corresponding continuous annular surfaces. These two networks have the same number N2 of magnetic wires 21 and 22, separated by a line defined by space or a substantially non-magnetic material, and therefore have the same period P2. They are angularly offset by half a period P2/2 and therefore 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 extending into the outer annular surface and a second combined pattern 26 extending into the inner annular surface are obtained in projection onto parallel geometric planes. These two combined patterns are continuous and rotate together at a second angular frequency F2, i.e., F2 = (F1·N1)/(-2). When the number |ΔN| = 2, each combined pattern alternates between two regions with a high proportion of magnetic surface and two regions with a lower proportion of magnetic surface.

Given the phase shift between circular networks 19 and 20, the two combined patterns 25 and 26 also have a phase shift of 180°. Generally speaking, the alternation of areas containing a high proportion of magnetic surface and areas containing a lower proportion of magnetic surface defines a periodic combined pattern with an angular period P3, whose value is equal to 360° divided by the absolute value of the difference between numbers N1 and N2, |ΔN|, i.e., P3 = 360°/|ΔN|. In the example of FIG2 , the two combined patterns 25 and 26 each have a period P3 = 360°/2 = 180°. It should be noted that the embodiment of FIG2 is a specific case of a single circular network on the escape wheel, which extends into an annular surface corresponding to the two concentric annular surfaces of the two circular networks of the second magnetic structure. In a variant, the first magnetic structure also includes two separate circular networks with the same period P1. For example, these two circular networks have an angular deviation of P1/4, and the two circular networks of the second magnetic structure have an angular deviation of P2/4. It should also be noted that, in a variant, the two circular networks of the first magnetic structure have different periods P1 and P2 , and likewise the two circular networks of the second magnetic structure, by reversing the periods P1 and P2 between the two magnetic structures.

As shown in Figures 3A and 3B, the magnetic escapement 24 includes at least one magnet 32 mounted on a resonator and magnetically coupled to two magnetic structures. The two magnetic structures are superimposed so that, when the mechanical timepiece movement is in operation, the magnet undergoes periodic resonant motion at a resonant frequency. According to the present invention, during its magnetic interaction with the two magnetic structures, the magnet undergoes a motion associated with a resulting composite pattern that can rotate much faster than the escape wheel. Figures 3A and 3B illustrate, partially in cross-section, the magnetic interaction of magnet 32 with the two circular networks 3 and 19 of Figure 2. The magnet has a magnetization axis perpendicular to the geometric surface of the composite pattern. In Figure 3A, the magnet is located above a first region of the composite pattern containing a large proportion of magnetic surface. In this first region, the two networks are angularly offset so that they together form a relatively continuous magnetic path for the magnet's field lines 34A; this results in reduced magnetic resistance to the magnet. In Figure 3B, the magnet is located above a second region of the composite pattern containing a smaller proportion of magnetic surface. In this second region, the two networks are substantially superimposed so that the magnetic circuit for the magnets in these networks is interrupted by empty spaces or is formed by non-magnetic material arranged between the magnetic wires. It will be understood that the field lines 34B of the magnets at the location of the two networks must pass through the empty spaces or non-magnetic areas. Therefore, the magnetic resistance increases relative to the situation in Figure 3A. The result of this change in magnetic resistance is a change in the magnetic potential energy Epot shown as curve 36 in Figure 3C. This change in magnetic potential energy Epot generates a force on the magnet, making it possible to set the magnet to rotate and/or maintain resonant motion using two concentric annular magnetic tracks.

FIG4 shows a first embodiment of a regulating device 40 according to the first type. This regulating device includes a magnetic escapement 24 as described in FIG2 . Two superimposed magnetic structures 2 and 18 form two periodic composite patterns 25 and 26, phase-shifted by 180°, as described above. The resonator 42 is formed by a tuning fork having two branches 43 and 44. Two magnets 46 and 48 with axial magnetization are attached to the free ends of these branches, respectively. In their rest position, the centers of the two magnets lie above a circle 50 defining the null circle. This circle 50 is selected so that it coincides with the circle separating two consecutive composite patterns. Similar to the device described in the "Background Art" section, these two composite patterns form two magnetic tracks with periodic variations in the potential energy of the oscillator formed by the tuning fork 42 and the magnetic escapement. Each magnet oscillates according to a substantially radial degree of freedom. It is alternately attracted by the low reluctance regions of the two magnetic tracks. Above each track, the magnet accumulates magnetic potential energy, braking the escape wheel. By crossing the null circle, they each receive an impulse for maintaining resonance, provided they undergo a jump in magnetic potential energy due to the angular deviation of the two periodic combined patterns 25 and 26. Thus, in a rotating reference frame relative to the escape wheel, the magnets follow a trajectory 50 corresponding to an oscillation according to the degree of freedom of each magnet.

Regarding the reduction ratio between the tuning fork's oscillation frequency Fosc and the rotation frequency F1 of the escape wheel carrying the first magnetic structure (when the second magnetic structure is not rotating), on the one hand, the rotation frequency F2 of the combined patterns 25 and 26 is equal to F1·N1/ΔN (ΔN being the difference between N1 and N2). On the other hand, the oscillation frequency Fosc is equal to F2·ΔN. Regardless of ΔN, the relationship Fosc = F2·ΔN = F1·N1 holds. Therefore, the reduction ratio is independent of the number ΔN. This fact can be exploited by choosing a small ΔN, in particular |ΔN| = 2 or 4. A particular feature of the present invention is that, for a large reduction ratio, periodic combined patterns with a large period can be produced, and thus, large magnets can be used, which have a relatively large magnetic interaction area with the magnetic structure defining the combined pattern, without requiring a reduction in the reduction ratio. To ensure that the tuning fork's magnets oscillate symmetrically with respect to the axis of rotation 6, the number ΔN is an even number. In FIG. 4 , ΔN = -2.

FIG5 shows a second embodiment of a regulating device 60 according to the present invention, comprising a magnetic escapement 24A formed by a first magnetic structure 2 defining a first circular network 3, which is mounted on a shaft and rotates about an axis of rotation 6. Furthermore, the magnetic escapement is formed by a second magnetic structure 18 defining two phase-shifted circular networks, as described above with reference to FIGs. 2 and 4. This second embodiment differs from the previous one in that the resonating portion 68 of the resonator 70 comprises two magnets 32 and 62, respectively disposed on either side of the two magnetic structures, forming the magnetic escapement 24A. This configuration solves the problem of the first embodiment by the fact that, as long as the two magnetic structures are located at approximately equal distances from the respective magnets opposing them, the axial attractive forces exerted by the magnetic structures on the two magnets largely compensate for each other. The same applies to the attractive forces exerted by the two magnets on the entirety of the two magnetic structures.

Two magnets are fixed to the ends of a non-magnetic element in the form of a U. The resonator is represented by a schematic spring. The resonant part 68 can be fixed, for example, to the free end of a tuning fork. Its operation is similar to that of the first embodiment. The magnets are magnetically coupled to the circular network in the manner described above. They are aligned axially so as to be perpendicular to the zero circle. The structure 18 is fixed and supported by a disk 66, which is formed from a non-magnetic material. Lateral recesses are provided in the disk to allow the resonant part 68 to pass from under the structure 18. It should be noted that in the variant shown, the magnetic structures 2 and 18 each have an inner annular part and an outer annular part connecting the lines of the circular networks 3, 19 and 20.

In the variant shown, the two magnets have axial magnetizations in opposite directions. This configuration is advantageous because it makes it possible to amplify the magnetic interaction, as shown in FIG6 . The first image (Δx=0) is a cross-sectional view similar to FIG3B , while the second image (Δx=0.5·P3) is a cross-sectional view similar to FIG3A . In the second image, the magnetic interaction is at a first approximation approximately twice that of the case with a single magnet, since the two superimposed circular networks roughly form a screen between the two magnets. In contrast, in the first image, the two magnets repel each other in the empty space between the magnetic wires. This repulsive force increases the magnetic potential energy Epot. The curve 74 of Epot has a profile similar to that of the curve 36 of FIG3C . However, computer simulations have made it possible to determine a priori that the amplitude of the periodic curve 74 is a certain order of magnitude greater than the amplitude of the periodic curve 36.

In the variant shown in FIG7 , the two magnets have axial magnetization directed in the same direction. The lines of the circular network are here arranged to be thicker. On the magnetic potential energy diagram, it can be seen that the Epot curve 76 is the inversion of the curve 74 . Indeed, since the magnetic flux between the two magnets in this variant is directed approximately axially, the regions of the combined pattern containing a greater proportion of magnetic surface have a greater magnetic resistance for the two magnets than would be the case if the two magnets were facing regions containing a smaller proportion of magnetic surface. In the illustrated configuration, the amplitude of the periodic curve 76 is, a priori, approximately half that of the periodic curve 74 .

A third embodiment of a regulating device 80 of the first type is shown in FIG8 . Elements common to the embodiment of FIG5 will not be described in detail. This regulating device comprises a resonator 70 and a magnetic escapement 24B composed of a first magnetic structure 2A defining a first circular network similar to network 3 in FIG2 , and a second magnetic structure 18A defining two concentric circular networks corresponding to networks 19 and 20 in FIG2 . It should be noted that in this example, there are two concentric circular networks forming the escape wheel and rotating about axis 6 , with structure 2A being fixedly mounted in the watch movement. This third embodiment differs from the previous one primarily in that it includes a third magnetic structure 82 defining a fourth circular network, similar to the first network, extending into the annular surface of the second and third phase-shifted networks comprising structure 18A. This third structure is integral with the first structure 2A, the fourth circular network being identical to the first, and their magnetic lines axially superimposed (without angular deviation between the two networks). The first and fourth networks are located on either side of the magnetic structure 18A forming the second and third networks, respectively.

Magnetic structure 18A comprises a continuous central annular portion. Between the second and third networks, a continuous annular intermediate portion, preferably made of a magnetic material, is provided. Furthermore, a continuous annular peripheral portion is provided. These three continuous annular portions allow for a magnetic structure 18A that is integrated with the magnetic wires of the two networks fixed at either end. To ensure that the continuous annular region does not interfere with the operation of the magnetic escapement, the circular network extends over a radial length that is significantly greater than the radial length of the oscillating magnet. This structure 18A is retained in a non-magnetic hub 86 mounted on the shaft of the escape wheel. The two fixed structures 2A and 82 each comprise two continuous annular peripheral portions connected by non-magnetic struts 84. This embodiment resolves the issues remaining in the second embodiment. In effect, the two superimposed magnetic structures are attracted to each other due to the magnetic flux of the magnets. Due to the superposition of the three magnetic structures, these attractive forces are largely offset by the presence of the magnetic intermediate structure positioned approximately between the other two magnetic structures. It should be noted that various variations are conceivable. In a first variant, two concentric, phase-shifted networks are provided in the first and third magnetic structures, while the second magnetic structure forms a single, extended circular network. In another variant, the first and third external structures are mounted on the axle of the escape wheel and rotate integrally, while the second intermediate structure is fixedly mounted in the timepiece movement.

A variant embodiment will be briefly described with the aid of FIG9 . This regulating device 90 differs in that a magnetic escapement 24C comprises two magnetic structures 2B and 82A situated on either side of the escape wheel, connected to the timepiece movement via two non-magnetic supports 94 and 96 fixed and centered in two bridges 95 and 97 respectively, and in that the two intermediate circular networks 19 and 20 are doubled and designed on either side of a non-magnetic disc 92 forming the escape wheel.

A first embodiment of a second device for regulating the operation of a timepiece movement will be described with reference to FIG10 . The regulating device 100 comprises a magnetic escapement 12 as described with reference to FIG1 , with the sole difference being that the superimposed circular network has more magnetic threads and, therefore, a smaller angular period. However, as shown in FIG1 , the difference between the magnetic threads, |ΔN|, is equal to 1 (|ΔN|=1). An escape wheel (not shown in its entirety) carries one of the two magnetic structures forming the combined pattern 14 and rotates about the central axis 6 of the circular network defined by these two magnetic structures. The regulating device also comprises a resonator 102, the resonating portion of which comprises a magnet 104. This resonator has two degrees of freedom, in whose resonant mode the magnet 104 essentially follows a circular path at a certain angular resonant frequency without rotating on its own. To this end, the resonator is designed so that, when the center of the magnet moves away from the axis of rotation 6, its resonating 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. Therefore, the resonator is designed so that the center of magnet 104 follows a substantially circular trajectory about the axis of rotation at a certain angular resonant frequency, Fres, as it moves away from the axis of rotation, and so that the magnet is set in rotation with a substantially constant torque. It should be noted that in this system, this trajectory can also be elliptical without disrupting isochronism. In this latter case, it is ensured that the magnet remains at least partially superimposed on the combined pattern formed by the superimposed circular magnetic network. In Figure 10, such a resonator is schematically represented by a magnet 104 connected to two orthogonal springs 106 and 108, which have substantially the same spring constant and are mounted on supports 110 and 112, respectively, which slide frictionlessly in two orthogonal tracks 114 and 116, respectively; the supports are schematically represented by a theoretically inertial carriage with wheels. The vector sum of the radial forces of the springs generates a restoring force (centripetal force) that allows the inertial portion of the resonator to follow a substantially circular or elliptical trajectory.

Thus, the annular regions of the first and second magnetic structures defining the combined pattern 14, comprising a first region 15 with a large proportion of magnetic surface area and a second region 16 with a smaller proportion of magnetic surface area, are magnetically coupled to the magnet 104, such that the magnet is set in rotation by the magnetic interaction torque induced by the combined pattern rotating at an angular frequency ω. The combined pattern rotates when a driving torque within a usable range of driving torques is applied to the escape wheel. The angular frequency ω of the combined pattern is controlled at an angular resonant frequency Fres within this usable range of torques. This usable range of torques is selected so that the magnetic interaction torque remains below the maximum magnetic interaction torque and so that, for any driving torque within this usable range, the circle described by the centers of the magnets has a radius within the radial range of the combined pattern 14. This magnetic interaction in the resonator has the effect of synchronizing the angular frequency ω of the escape wheel to the resonant frequency Fres of the resonator. The combined pattern 14 causes the potential energy Epot in the resonator to vary between a minimum energy when the magnet is located above the first region 15 and a maximum energy when the magnet is located above the second region 16, depending on the relative angular position of the magnet and the combined pattern. The angular gradient of this potential energy generates a tangential entrainment force on the magnet.To avoid synchronization losses, it is necessary to ensure that the braking torque exerted by the magnet on the escape wheel remains below the maximum magnetic interaction torque that depends on the maximum value of the gradient of the potential energy Epot.

In a preferred variant, the resonator is designed and the usable range of drive torques is selected such that, for any drive torque within this usable range, the magnet 104 is completely superimposed on the combined pattern 14 .

FIG11 shows a variant embodiment of the regulating device of FIG10 . Elements already described above will not be described again. This variant differs from the previous embodiment in that the magnetic escapement 24A is formed by two superimposed circular networks, the absolute value of the difference between the number of magnetic threads, |ΔN|, equal to 2, i.e., |ΔN| = 2, similar to the embodiment of one of the two combined patterns in FIG2 . Consequently, combined pattern 25A alternates between two regions 15A with a large proportion of magnetic surface and two regions 16A with a smaller proportion of magnetic surface. Since the difference in magnetic potential energy between the extremes is approximately the same as in the previous variant, but this difference affects half the angular range, the maximum magnetic interaction force is approximately doubled. In contrast, the ratio between the angular frequency of combined pattern 25A and the rotational frequency of the escape wheel carrying one of the two circular magnetic networks is half that of the previous variant. Consequently, the available range of driving torque is increased, but the multiplication ratio between the frequency of the escape wheel and the resonant frequency is reduced. It should be noted that the magnet 104 has an angular deviation α of less than 90° and in particular less than 45°, which varies according to the torque caused by the magnetic interaction between the magnet 104 and the combined pattern 25A.

Figure 12 schematically illustrates a second embodiment of a second regulating device according to the present invention. This regulating device 130 is a specific embodiment implementing the physical features mentioned above in the description of the first embodiment. A resonator 132 is formed by a rod 134, elastically deformable in two degrees of freedom, roughly defining a portion of a sphere. The rod is secured in a socket 136. The rod carries a magnet 104A at its free end. The magnetic escapement structure 12A is similar to the magnetic escapement described in Figures 2 and 10 . It comprises a first magnetic structure 2A forming a first circular network 3A, and a second magnetic structure 8A forming a second circular network 9A. The magnetic wires 4A of the first circular network extend into a first truncated surface, while the magnetic wires 10A of the second circular network extend into a second truncated surface parallel to the first. As described above, a pattern 14A similar to the aforementioned pattern 14 is obtained. The first magnetic structure 2A is mounted on an axle 138, which is guided in rotation by two ball bearings disposed in a bridge 142. The second magnetic structure is secured and mounted on a non-magnetic support 146. Structure 2A comprises a continuous inner annular portion connecting magnetic wire 4A, and structure 8A comprises a continuous outer annular portion connecting magnetic wire 10A. A truncated portion 140 is provided at one end of shaft 138, forming a central circular limit stop for magnet 104A. This limit stop is designed so that, when no driving torque is being supplied to the escape wheel, here constituted by first magnetic structure 2A, shaft 138, and pinion 144, at least a substantial portion of this magnet remains superimposed on pattern 14A. This pinion is connected to the counting mechanism of a mechanical timepiece movement, via which it receives the driving torque provided by a motor device (not shown).

Finally, in general, the invention relates to a mechanical timepiece movement comprising a regulating organ, a counter mechanism regulated by the regulating organ, and motor means for driving the counter mechanism and maintaining the resonant mode of the regulating organ. This timepiece movement is characterized by the fact that it comprises a magnetic escapement according to the invention or a regulating organ according to the invention.

Claims (30)

1. A magnetic escapement mechanism for equipping a mechanical watch movement and including an escape wheel driven by a motor and coupled to a resonator of the mechanical watch movement, the escape wheel including a first magnetic structure defining a first periodic pattern having a first angular period P1 within a non-zero radial range of the escape wheel, such that 360°/P1 equals a first integer N1, the magnetic escapement mechanism including at least one magnet mounted on the resonator and magnetically coupled to the escape wheel such that when the mechanical watch movement is in operation, the magnet has periodic resonant motion at a certain resonant frequency, and the escape wheel moves at a frequency proportional to the resonant frequency. The magnetic escapement mechanism, characterized in that: the magnetic escapement mechanism includes a second magnetic structure, the second magnetic structure being parallel to the first magnetic structure and defining a second periodic pattern having a second angular period P2 within the radial range, such that 360°/P2 is equal to a second integer N2 different from the integer N1, the absolute value of the difference between the integers N1 and N2, |ΔN|, is a number less than or equal to N/2, i.e., |ΔN|<＝N/2, where N is the smaller of the integers N1 and N2; the first and second magnetic structures are designed such that: when the watch movement is operating, the first magnetic structure is relative to the second magnetic structure at a first relative angular frequency F1. The first and second periodic patterns are selected such that: within the _radial range, the first and second periodic patterns generate a combined pattern in projections onto geometric surfaces parallel to the first and second magnetic structures, the combined pattern being coupled to the magnet and alternately defining at least the number |ΔN| first regions comprising a magnetic surface of a first proportion and at least the number |ΔN| second regions comprising a magnetic surface of a second proportion less than the first proportion, and such that the combined pattern rotates relative to the second magnetic structure at a second relative angular frequency F2 _rel , the second relative angular frequency being equal to the first relative angular frequency F1 _rel multiplied by the integer N1 and divided by the difference ΔN between the integers N1 and N2, i.e., F2 _rel = F1 _rel · N1/ΔN, where ΔN = N1 – N2. 2. The magnetic escapement mechanism according to claim 1, wherein the magnet has a magnetization axis perpendicular to the geometric surface of the combined pattern. 3. The magnetic escapement mechanism according to claim 1, characterized in that the combined pattern defines a periodic combined pattern, the periodic combined pattern alternately having the number |ΔN| first regions and the number |ΔN| second regions, any first region and an adjacent second region define the angular period P3 of the periodic combined pattern, the value of P3 being equal to 360° divided by the number |ΔN|, i.e., P3 = 360°/|ΔN|. 4. The magnetic escapement mechanism according to claim 3, characterized in that the first periodic pattern forms a first circular network of lines made of magnetic material, the lines being separated by lines defined by blank spaces or substantially non-magnetic material, and the second periodic pattern forms a second circular network of lines also made of magnetic material, the lines of the second circular network being separated by lines defined by blank spaces or substantially non-magnetic material. 5. The magnetic escapement mechanism according to claim 4, wherein the lines of the first circular network made of magnetic material extend substantially at half of the first angular period P1, and the lines of the second circular network made of magnetic material extend substantially at half of the second angular period P2. 6. An adjusting device for regulating the operation of a watch movement comprising a magnetic escapement mechanism according to any one of claims 3 to 5, characterized in that: the adjusting device comprises a resonator, a resonant portion of which supports the magnet oscillates according to one degree of freedom during operation of the watch movement; the resonator is designed such that, for any angular position of the escape wheel, the center of the magnet is substantially located on a zero-position circle in the inoperable position of the magnet, the zero-position circle being centered on the rotation axis of the escape wheel and transversely intersected by the degree of freedom of the resonant portion of the resonator; the periodic combination pattern is located on a first side of the zero-position circle, projected perpendicularly into the geometric surface, and an annular region of the first and second magnetic structures defined by the radial range is magnetically coupled to the magnet at the first alternation of each cycle of the oscillation, such that, for each cycle of the oscillation, the periodic combination pattern rotates an angular distance equal to the angular period P3. 7. The adjustment device according to claim 6, wherein the periodic combination pattern is a first periodic combination pattern and the radial range is a first radial range; characterized in that: within a non-zero second radial range of the escape wheel located on the other side of the zero-position circle relative to the first radial range, the first and second magnetic structures respectively define a third periodic pattern and a fourth periodic pattern that generate the second periodic combination pattern, the second periodic combination pattern alternately having the number |ΔN| third regions and the number |ΔN| fourth regions, the third regions comprising a magnetic surface of a third ratio greater than the second ratio, the fourth regions comprising a magnetic surface of a fourth ratio less than the first and third ratios, the second periodic combination pattern having the angular period P3; and the second periodic combination pattern is angularly offset upward relative to the first periodic combination pattern by half of the angular period P3, the second periodic combination pattern also rotating at the second relative angular frequency F2 _rel , the annular region of the first and second magnetic structures defined by the second radial range being magnetically coupled to the magnet at the second alternation of each cycle of the oscillation. 8. The adjusting device according to claim 7, characterized in that, when claim 6 refers to claim 4, the third periodic pattern forms a third circular network of lines made of magnetic material, the lines being separated by blank spaces or lines defined by substantially non-magnetic material, and the fourth periodic pattern forms a fourth circular network of lines also made of magnetic material, the lines of the fourth circular network being separated by blank spaces or lines defined by substantially non-magnetic material, the third and fourth circular networks having angular periods equal to the first and second angular periods P1 and P2, respectively. 9. The adjusting device according to claim 8, characterized in that: the first and second periodic combination patterns are substantially continuous; and the first and third circular networks or the second and fourth circular networks together form the same circular network extending at least in the first and second radial ranges. 10. The adjustment device according to claim 7, characterized in that: the resonator is formed by a tuning fork having two branches, the magnet is formed by a first magnet fixed at the free end of the first branch, the resonator further includes a second magnet fixed at the free end of the second branch; and the number |ΔN| is an even number. 11. The adjusting device according to claim 10, wherein the number |ΔN| is equal to 2, that is, |ΔN|＝2. 12. An adjusting device for regulating the operation of a watch movement comprising a magnetic escapement mechanism according to any one of claims 1 to 5, characterized in that: the adjusting device comprises a resonator having a resonant portion supporting the magnet, the resonator being designed such that when the center of the magnet moves away from the axis of rotation of the escape wheel, the resonant portion is subjected to a radial restoring force relative to the axis of rotation, and such that when the center of the magnet moves away from the axis of rotation, the center of the magnet substantially follows a circular or elliptical trajectory centered on the axis of rotation at a certain angular resonant frequency, and such that the magnet is set to rotate with a substantially constant torque. ; and, the annular regions of the first and second magnetic structures defined by the radial range are magnetically coupled to the magnet, such that the magnet is set to rotate by a magnetic interaction torque derived from the combined pattern that rotates when a drive torque within the available range of the drive torque is provided to the escape wheel, the angular frequency of the combined pattern being controlled at the angular resonant frequency within the available range of the torque, the available range of the torque being selected such that the magnetic interaction torque remains below the maximum magnetic interaction torque, and such that for any drive torque within the available range, the trajectory of the center of the magnet has a radius within the radial range. 13. The adjustment device according to claim 12, wherein the resonator is designed and the available range of the driving torque is selected such that: for any driving torque within the available range, the magnet is completely superimposed on the combined pattern. 14. The adjusting device according to claim 12, wherein the number |ΔN| is equal to 1 or 2, that is, |ΔN|＝1 or |ΔN|＝2. 15. The adjusting device according to claim 13, wherein the adjusting device includes a central circular stop for the magnet, the stop being designed such that when no driving torque is provided to the escape wheel, at least the main portion of the magnet remains superimposed on the combined pattern. 16. The adjusting device according to claim 6, wherein the magnet is a first magnet; characterized in that the magnetic escapement mechanism includes a second magnet mounted on the resonator and supported by the resonant portion or another resonant portion of the resonator, the second magnet being designed relative to the first magnet on the other side of the first and second magnetic structures such that the second magnet is aligned with the first magnet in a direction substantially parallel to the axis of rotation, and such that the second magnet has a periodic resonant motion at the resonant frequency similar to the periodic resonant motion of the first magnet. 17. The adjusting device according to claim 12, wherein the magnet is a first magnet; characterized in that the magnetic escapement mechanism includes a second magnet mounted on the resonator and supported by the resonant portion or another resonant portion of the resonator, the second magnet being designed relative to the first magnet on the other side of the first and second magnetic structures such that the second magnet is aligned with the first magnet in a direction substantially parallel to the axis of rotation, and such that the second magnet has a periodic resonant motion at the resonant frequency similar to the periodic resonant motion of the first magnet. 18. The adjusting device according to claim 16, wherein the second magnet has a magnetization axis parallel to and in the opposite direction to the magnetization axis of the first magnet. 19. The adjusting device according to claim 16, wherein the second magnet has a magnetization axis parallel to and in the same direction as the magnetization axis of the first magnet. 20. The adjusting device according to claim 16, wherein the magnetic escapement mechanism includes a third magnetic structure, the third magnetic structure defining a periodic pattern substantially identical to and superimposed on the periodic pattern defined by the first or second magnetic structure, the third magnetic structure rotating integrally with the first or second magnetic structure when the first or second magnetic structure rotates, and two magnetic structures having the same periodic pattern are respectively located on both sides of magnetic structures with different periodic patterns. 21. The adjusting device according to claim 17, wherein the second magnet has a magnetization axis parallel to and in the opposite direction to the magnetization axis of the first magnet. 22. The adjusting device according to claim 17, wherein the second magnet has a magnetization axis parallel to and in the same direction as the magnetization axis of the first magnet. 23. The adjusting device according to claim 17, wherein the magnetic escapement mechanism includes a third magnetic structure, the third magnetic structure defining a periodic pattern substantially the same as and superimposed on the periodic pattern defined by the first or second magnetic structure, the third magnetic structure rotating integrally with the first or second magnetic structure when the first or second magnetic structure rotates, and two magnetic structures having the same periodic pattern are respectively located on both sides of magnetic structures with different periodic patterns. 24. The regulating device for regulating the operation of a watch movement according to claim 6, characterized in that the second magnetic structure is fixed relative to the watch movement, and the first relative angular frequency F1 _rel defines the angular frequency of the escapement wheel relative to the watch movement. 25. The regulating device for regulating the operation of a watch movement according to claim 12, characterized in that the second magnetic structure is fixed relative to the watch movement, and the first relative angular frequency F1 _rel defines the angular frequency of the escapement wheel relative to the watch movement. 26. A mechanical watch movement, comprising an adjusting device, a counting mechanism whose speed is adjusted by the adjusting device, and a motor device for driving the counting mechanism and maintaining the resonant mode of the adjusting device, characterized in that the adjusting device comprises a magnetic escapement mechanism according to any one of claims 1 to 5. 27. A mechanical watch movement, comprising an adjustment device, a counting mechanism whose speed is adjusted by the adjustment device, and a motor device for driving the counting mechanism and maintaining the resonant mode of the adjustment device, characterized in that the adjustment device is the adjustment device according to claim 6. 28. A mechanical watch movement, comprising an adjustment device, a counting mechanism whose speed is adjusted by the adjustment device, and a motor device for driving the counting mechanism and maintaining the resonant mode of the adjustment device, characterized in that the adjustment device is the adjustment device according to claim 12. 29. A mechanical watch movement, comprising an adjustment device, a counting mechanism whose speed is adjusted by the adjustment device, and a motor device for driving the counting mechanism and maintaining the resonant mode of the adjustment device, characterized in that the adjustment device is the adjustment device according to claim 16. 30. A mechanical watch movement, comprising an adjustment device, a counting mechanism whose speed is adjusted by the adjustment device, and a motor device for driving the counting mechanism and maintaining the resonant mode of the adjustment device, characterized in that the adjustment device is the adjustment device according to claim 17.