EP3254158A1

EP3254158A1 - Isochronous timepiece resonator

Info

Publication number: EP3254158A1
Application number: EP16701499.2A
Authority: EP
Inventors: Pascal Winkler; Jean-Luc Helfer; Gianni Di Domenico; Thierry Conus
Original assignee: ETA Manufacture Horlogere Suisse SA
Current assignee: ETA Manufacture Horlogere Suisse SA
Priority date: 2015-02-03
Filing date: 2016-01-26
Publication date: 2017-12-13
Anticipated expiration: 2036-01-26
Also published as: CN106662839A; JP2017514152A; EP3254158B1; US9983549B2; WO2016124436A1; CN106662839B; JP6326549B2; US20170123380A1

Abstract

The invention relates to an isochronous timepiece oscillator mechanism (1), including a stationary mounting (2) supporting a crossmember (4) supporting N primary resonators (10) each including a mass (5) supported by a rotary flexible guide (20) attached to said crossmember (4). Each primary resonator (10) has a centre of mass (CM) which, when inoperative, is on the virtual pivoting axis (APV) of the rotary flexible guide (20) thereof and is arranged to oscillate by rotating said virtual pivoting axis (APV), said primary resonators (10) are arranged with symmetry of rotation of order N about a main axis (AP) parallel to the virtual pivoting axes (APV), and the oscillation movements of any two primary resonators (10) are out of phase with the value of the central angle formed by the respective virtual pivoting axes thereof (APV) with the main axis (AP). The invention also relates to a clock movement (100) including such an isochronous oscillator mechanism (1) and to a watch (200) including such a movement (100).

Description

Isochronous timepiece resonator

Field of the invention

The invention relates to an isochronous clock oscillator mechanism, comprising a fixed support which carries a carrier beam of a plurality of N primary resonators each comprising at least one mass carried by a flexible rotary guide fixed to said cross-member.

The invention also relates to a watch movement comprising at least one such isochronous oscillator mechanism.

The invention also relates to a watch comprising at least one such movement.

The invention relates to the field of clock oscillator mechanisms and regulators, in particular for mechanical movements.

Background of the invention

In a classic mechanical watch, the friction of the air on the balance, the friction of the pivots in their bearings and the piton reactions, limit the quality factor of the resonator. We try to remove the friction of the pivots and the reactions of the embedding.

For a watch, the isochronism of the movement must be optimal in all positions in space, which implies the design of movements able to compensate for the effects of gravitation on their constituents.

Older documents describe oscillators comprising a plurality of primary resonators having flexible branches, arranged relative to each other so as to average their errors.

A first type of oscillator with coupled primary resonators is known as a tuning fork whose each branch is formed by a primary resonator; however, such a system is very sensitive to variations in position in space.

The patent CH 451021 in the name of Ebauches SA thus describes a symmetrical oscillator in U whose two flexible branches vibrate in tuning fork mode, each being connected to a rigid arm forming a counterweight, and each primary resonator thus formed is arranged so that the instant center of rotation coincides with the center of gravity, so that the frequency of the oscillator does not change substantially during changes in position in the center of gravity. The transition to a U-shaped architecture with extended branches is better than the U-shape of the prior art. However, the instantaneous center of rotation constantly moves during the oscillation of each primary resonator.

The patent CH 46203 also in the name of Ebauches SA is a variant of the previous, comprising a counting device transforming the oscillating movements of one of the two resonators into rotary movements of a counting wheel, this counting device being attached to the one of these rigid arms, so that the counting device is insensitive to accelerations and in particular to shocks.

GB 1293159 in the name of SEIKO develops a theory based on the influence on the regularity of operation of the derivative of the displacement of the center of mass with respect to the angle of rotation, and seeks a displacement along a straight line of the center of mass of each primary resonator, to optimize the influence on walking. For this purpose, the center of mass is positioned two-thirds of the bending blade used in this system, to theoretically cancel the effect on walking in the vertical positions. However the center of mass moves a lot, and such a system remains sensitive to shocks. Moreover, this theory is based on a geometrical approximation, because in reality the deformation of the flexible blade is no longer really an arc of a circle, and the presumably rectilinear displacement of the center of mass is not verified. Summary of the invention

The invention proposes to jointly solve the problem of isochronism and that of obtaining the best possible quality factor. It is, in a way, to combine the respective advantages of known mechanisms using as resonator, or a balance-spiral assembly relatively insensitive to differences in position in space in its developments and most advanced montages but whose quality factor is strongly limited by the pivoting and the different losses, or a tuning fork with parallel blades which, freeing from the pivoting, has a factor of better quality than a sprung balance but is very sensitive to the position in the space.

For this purpose, the invention relates to an isochronous clock oscillator mechanism according to claim 1.

The invention also relates to a watch comprising at least one such movement. Brief description of the drawings

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

FIG. 1 is a diagrammatic plan view of an isochronous clock oscillator mechanism according to the invention, of the tuning fork type, comprising a fixed support which carries, by a main elastic connection, a carrier cross-section of two primary resonators. planes, symmetrical with respect to a plane of symmetry, and each comprising a mass carried by an elastic flexible blade arranged to work in bending and embedded in the cross;

FIG. 2 simulates, schematically:

o the influence of the gravity on a first mass suspended upwards by means of a flexible blade, and the gait diagram corresponding to a delay of a certain value,

o the influence of gravity on a second identical mass suspended downwards by means of an identical flexible blade, and the gait diagram corresponding to an advance of a certain value,

o the influence of gravity on a mechanism according to the invention which combines the two previous ones, and the gait diagram corresponding to a virtually zero defect;

- Figure 3 shows schematically and in plan view, a first embodiment of the invention, said "tuning fork H" in a simplified version;

FIG. 4 is a diagrammatic perspective view of a more elaborate H-tuning fork shown in FIG. 5 in an exploded form; FIG. 6 is an exploded view, with a local detail, of an H tuning fork in a configuration close to that of FIGS. 4 and 5, without axes, and FIGS. 7A to 7H show the components and the assembly of this H tuning fork. of Figure 6;

- Figures 8 and 9 show schematically and in plan view, a second embodiment of the invention, called "tuning fork horns" in simplified versions;

Figure 10 shows, schematically and in perspective, and with a local detail, a more elaborate variant of tuning fork horns;

FIG. 11 illustrates, in exploded form, a forked horn fork in a configuration similar to that of FIG. 10, without axes, and FIGS. 12A to 12H represent the components and the assembly of this H-tuning fork of FIG. ;

FIGS. 13 and 14 show, in perspective and in plan view, a torsion tuning fork which comprises arms, each provided with a mass at its distal end, and oscillating in parallel planes and symmetrically with respect to a axis parallel to these two planes;

FIG. 15 illustrates another variant of tuning fork with two resonators, each comprising a spiral spring recessed at a first end on a common cross-piece and having a mass at a second distal end, these two resonators extending in two parallel planes and being , in projection on one of these planes, symmetrical with respect to a plane of symmetry which is perpendicular to these two planes;

FIG. 16 schematically and in plan view shows a mechanism similar to the goat horn tuning fork of FIG. 8, which comprises, at each end of the cross member, a pair of spirals both connected to the same mass. respective at their internal turn, and attached to the respective cross on both sides of this mass;

FIGS. 17 and 18 are diagrams illustrating surfaces cooperating in friction in case of drift, this friction increasing with the amplitude in the case of FIG. 18;

FIG. 19 represents, schematically and in perspective, and with a local detail, a variant in which the cross-member constitutes a surrounding frame; primary resonators, in an example of application to four resonators; FIG. 20 schematically and in plan view shows another variant of crossbar formed by a frame, in a straight-blade oscillator, constituting the counterpart of the H-tuning fork;

- Figure 21 shows schematically and in plan, another variant of a cross member formed by a frame in a spiral oscillator, constituting the pendulum of the tuning fork goat horns;

Fig. 22 is a block diagram showing a watch having a movement incorporating an isochronous oscillator mechanism according to the invention;

FIG. 23 is a diagrammatic plan view of an oscillator comprising three primary resonators mounted in a star;

FIG. 24 schematically and in plan view shows an oscillator comprising four identical primary resonators mounted in complete symmetry with each other;

- Figure 25 shows schematically and in plan, a cross-sectional flexible guide detail;

FIG. 26 is a diagrammatic plan view of a flexible guide detail with two crossed blades arranged in two different planes parallel to each other.

Detailed Description of the Preferred Embodiments

The invention proposes to realize a resonator mechanism with the least possible loss, and which is the least sensitive chronometrically to its orientation in the gravitational field.

The invention seeks to reduce losses, in particular due to friction of pivots, and displacements of the recess.

The inventive step is to remove the traditional pivots, while minimizing the movements of the center of mass and the reactions of the support.

A mechanical resonator necessarily comprises at least one elastic element and an inertial element.

It is advantageous then to use an elastic element to provide the guiding function. This elastic element is then advantageously higher, thicker and more rigid than a conventional elastic element such as a spiral spring or the like, which leads to favor the use of flexible blades. It is advantageous to use rotary resonators whose center of mass coincides with the center of rotation, which reduces the influence of gravity and shocks in translation on the accuracy of the resonator.

The search for a high quality factor encourages the implementation of a tuning fork type structure.

However, the losses must be minimized: indeed, when a flexible blade resonator operates, the quality factor is good during the reciprocating movement, but the reaction torque to the embedding results in losses.

Also, the inventive step consists in producing a tuning fork isochronous resonator, with a plurality of primary resonators arranged in a symmetry geometry with respect to an axis, and together constituting a tuning fork.

The use of several primary resonators reduces the resistance to embedding, and average error.

To gain another order of magnitude compared with the prior art, as regards the insensitivity to the positions in space, the invention sets out to privilege the least possible displacement of the center of mass of each primary resonator, which offers, again, the advantage of a very good insensitivity to shocks. To promote this improvement, the invention proposes the construction of a structure comprising symmetries compensating for all efforts brought to the level of the fixation of the oscillator; for this purpose, it is advantageous to unfold the known U of the prior art to form a structure substantially in H.

The invention is more particularly described below, in a nonlimiting manner, in the preferred form of a tuning fork with two primary resonators symmetrical with respect to a plane of symmetry, which constitutes a particular advantageous case because of its simplicity. However, the invention is applicable to any number N of primary resonators: three, four, or more, provided that the symmetry of their relative arrangement and their relative temporal phase-shift make it possible to compensate for the effects of the reaction torques on embedding.

The assembly of these primary resonators is performed in such a way that they have at least one identical resonance mode, and that the resultant of the forces and torques at the embedding is zero.

Thus, the invention relates to an equilibrium isochronous oscillator mechanism 1, of the tuning fork type, comprising a fixed support 2 which carries a cross member 4 carrying a plurality of N primary resonators 10. Each primary resonator 10 comprises at least one mass 5 carried by a flexible rotary guide 20 fixed to the crossbar 4.

These primary resonators 10 constitute the equivalent of the arms that includes a conventional fork fork, and crosses 4 the equivalent of the common part of the tuning fork protruding these arms.

According to the invention, each primary resonator 10 has a center of mass CM which is located, at rest, on the virtual pivot axis APV of the rotary flexible guide 20 that this primary resonator 10 comprises.

And each primary resonator 10 is arranged to oscillate in a rotational movement about the virtual pivot axis APV.

The N primary resonators 10 are arranged in rotation symmetry of order N around a main axis AP which is parallel to all the virtual pivot axes APV which are parallel to each other.

And the oscillation motions of any two primary resonators of the oscillator mechanism 1 are out of phase with the value of the center angle their respective APV virtual pivot axes have with respect to the main axis AP.

In a particular embodiment, each rotary flexible guide 20 is, in projection on a plane perpendicular to the main axis AP, symmetrical with respect to a plane of symmetry PS passing through the virtual pivot axis APV of the rotary flexible guide 20 considered.

More particularly, each plane of symmetry PS passes through the main axis

AP.

Figure 24 illustrates an exemplary oscillator 1 having four identical primary resonators 10 mounted in complete symmetry with each other.

Advantageously, each rotary flexible guide 20 is arranged to cause a return torque proportional to the rotation angle of the mass 5, or masses 5 if there are several, with respect to the virtual pivot axis APV of the rotary flexible guide 20 considered.

The use of rotating flexible guides makes it possible to maintain the center of mass CM of each primary resonator 10 on the virtual pivot axis APV of the rotary flexible guide 20 considered, or in its immediate vicinity, for example during a strong acceleration or of a shock. The rotary primary resonators surround the crosspiece 4, and have at least one identical resonance mode, and are arranged to vibrate in a phase shift between them of the value 2π / Ν. Their arrangement of symmetry in space is such that the resultant of the forces and torques applied by the primary resonators 10 on the crossbar 4 is zero.

Each rotating flexible guide 20 constitutes an elastic return means, arranged to work in bending, and defines a substantially immobile virtual pivot axis APV.

In an advantageous embodiment, all the primary resonators 10 are identical to each other.

In a particular embodiment, the crosspiece 4 is fixed to the fixed support 2 by a main elastic connection 3, whose rigidity is greater than the rigidity of each rotary flexible guide 20. This characteristic ensures a coupling between the primary resonators 10. And, more in particular, the rigidity of this main elastic connection 3 is greater than the total of the rigidities of all the rotary flexible guides 20 that the isochronous oscillator mechanism 1 comprises. In a particular embodiment, each primary resonator 10 is arranged to oscillate in a plane around a neutral axis AN. Advantageously, the damping of the main elastic connection 3 is greater than the damping of each rotary flexible guide 20, and, more particularly, the damping of the main elastic connection 3 is greater than the total of the dampings of all the guides. rotary hoses 20 that comprise the primary resonators 10.

More particularly, and especially when the number N is odd, and all neutral axes AN are concurrent at a single point, or concurrent two by two at meeting points all located at the same distance from the main axis AP, such 23 in which the oscillator 1 comprises three primary resonators 10 mounted in a star, each with a neutral axis inclined with respect to the radial end of the main axis AP.

More particularly, all the neutral axes AN are angularly offset from the value 2ττ / Ν.

More particularly, and especially when the number N is even, all the neutral axes AN are parallel to each other or to each other.

In a particular embodiment, each flexible guide 20 is symmetrical with respect to the neutral axis AN of the primary resonator 10 to which it belongs. In a particular embodiment, the primary resonators 10 are even or two in number.

In a particular embodiment, the flexible guide 20 comprises at least one elastic flexible blade 6, and its virtual pivot axis APV is in the middle of the elastic flexible blade 6, that is to say halfway between the recesses of this flexible blade 6 in the crossbar 4 and in the at least one mass 5.

In a particular embodiment, the flexible guide 20 comprises at least crossed blades, in the same plane as visible in FIGS. 23 to 25, or in projection as visible in FIG. 26.

In a particular embodiment, the flexible guide 20 comprises at least one neck with a narrowed section, as can be seen in FIG.

In a particular embodiment, the primary resonators 10 are even or two in number, and each flexible guide 20 comprises at least one spiral winding around the virtual pivot axis APV which is located on the neutral axis AN of the primary resonator 10 to which it belongs. More particularly so as to ensure symmetry of operation, the spirals of these primary resonators 10 are arranged in pairs.

In a particular embodiment, at least the flexible guide 20 is made of micro-machinable material, or silicon and / or silicon oxide, or quartz, or DLC, in particular in the form of a monoblock component, while particularly when the flexible guide 20 is substantially planar. This one-piece component may also comprise a support for fixing the mass 5 or the masses 5, which are more particularly made of a material of higher density. This monobloc component can also be integral with the cross member 4, or with its main elastic connection 3, or even with the fixed support 2.

In an advantageous variant, each primary resonator 10 comprises thermal compensation means, at least at the level of the flexible guide 20. Preferably, each mass 5 is designed so that the center of mass CM remains invariant during temperature changes. .

More particularly, these thermal compensation means comprise at least one component made of élinvar, or of silicon and silicon oxide.

In an advantageous variant, at least one primary resonator 10 comprises frost limiting means arranged to cooperate in the event of an abutment abutment impact with complementary frost limiting means, which comprises, for example, a structure 5 and / or the cross member 4. For example, a mass 5 comprises a flowing finger, during the oscillation of the primary resonator 10, in an oblong groove of the fixed support 2, or vice versa.

In a particular application, at least two primary resonators 10 are coupled to each other, at least intermittently, by an escape wheel. For example, each primary resonator 10 carries, at a mass 5, an arm whose distal end is arranged to cooperate with the toothing of the escape wheel.

In a particular embodiment, the primary resonators 10 are arranged to oscillate each at a frequency between 1 Hz and 100 Hz.

Figures 1 to 17 illustrate examples with two primary resonators, Figure 19 illustrates an example with four primary resonators.

The primary resonators 10 are arranged in the space so that the resultant of their operating errors due to the gravitation is zero.

Preferably, the primary resonators 10 are rotatable, which makes the isochronous oscillator mechanism 1 according to the invention insensitive to gravitation.

Thus, each primary resonator 10 forms a rotary resonator, whose center of mass is on the place whose translations are minimal during rotation, and that one seeks to make null in normal operation. This is to minimize movements of the center of mass in the gravity field or under the effect of shocks, and thus improve the chronometry of the system.

The main elastic connection 3 between the cross member 4 and the fixed support 2 is preferably constituted by an elastic blade, it does not move substantially when the isochronous oscillator mechanism 1 oscillates in tuning fork mode. Indeed, the branches of the tuning fork constituted by the primary resonators 10 exchange energy movement through the cross 4, but the movements of the cross 4 are minimal.

The direction in which the centers of mass CM of the primary resonators 10 are moved is called the longitudinal direction X. A transverse direction Y is substantially perpendicular to this longitudinal direction X. A direction Z completes the direct trihedron.

In the variants illustrated in FIGS. 1 to 17, the cross member 4 is straight and extends in the longitudinal direction X. In an advantageous embodiment, but not limiting, which corresponds to the variants illustrated in the figures, all or part of the isochronous oscillator mechanism 1 is arranged symmetrically with respect to a symmetry plane PSY which extends parallel to the transverse direction Y.

Preferably, but not necessarily, the main elastic connection 3 extends along the main direction Y, as can be seen in the examples of FIGS. 1 to 17.

In a particular embodiment, the primary direction which connects the point of embedding on the crosspiece 4 of an elastic flexible blade 6 to the center of mass CM of the corresponding primary resonator 10, when the latter is at rest, is parallel to the longitudinal direction X.

FIG. 1 illustrates a simplified embodiment of an isochronous clock oscillator mechanism 1 according to the invention, of tuning fork type, comprising a fixed support 2 which carries, by a main elastic connection 3, made in the form of a flexible blade, a crossbar 4 carrying two planar primary resonators 10A, 10B, symmetrical with respect to a plane of symmetry PSY, and each having a mass, respectively 5A, 5B, carried by an elastic flexible blade, respectively 6A, 6B, constituting the flexible guide 20 of the primary resonator 10 concerned, arranged to work in bending and embedded in the crossbar 4, symmetrically with respect to the plane of symmetry PSY.

The choice of a geometric symmetry of construction facilitates the development. However, such an isochronous oscillator mechanism 1 can also be realized with non-symmetrical primary resonators, and operate correctly.

In the variants illustrated in FIGS. 1, 3, 6, 8 to 11, which are not limiting of the invention, the primary directions of the different primary resonators 10 which constitute this isochronous oscillator mechanism 1 are parallel to the longitudinal direction X, or merged.

For maximum efficiency, the flexible guides 20, in particular the flexible flexible blades 6, are arranged in such a way that the displacement of each center of mass CM of the given primary resonator 10 is minimal in the transverse direction Y where it is not provided that the displacements of the different centers of mass CM of the given primary resonators 10 are compensated with respect to one another in the longitudinal direction X: if, as in the case of the figures, the mechanism Isochronous oscillator 1 comprises two primary resonators 10A and 10B arranged back-to-back on either side of the crosspiece 4, their respective centers of mass CMA and CMB move essentially in the longitudinal direction X, but with displacements of the same value but opposite meanings.

The advantage of an arrangement according to the invention is to have elastic blades working in almost pure bending, which makes it possible to obtain an isochronous resonator. The torque is proportional to the angle a whose corresponding mass pivots. The frequency is therefore independent of the amplitude of the oscillation.

Preferably, the distance between the embedding of the resilient flexible blade 6 in the crossbar 4 and the center of mass CM is equal to the distance between the center of mass CM and the embedding of the elastic flexible blade 6 in the associated mass 5, as visible in FIG. The center of mass CM thus remains on the X axis, or in the immediate vicinity of the X axis, that is to say at a distance of a few micrometers.

In a particular embodiment, which allows economical manufacture, in particular by the implementation of micro-machinable materials according to the "MEMS," LIGA "or similar methods, each primary resonator 10 is arranged to oscillate in a plane.

In a particular embodiment, each primary resonator 10 is monolithic.

In a particular embodiment, the cross member 4 and the flexible guides 20, in particular the resilient flexible blades 6, primary resonators 10 form a monolithic assembly.

In a particular embodiment, the fixed support 2, the main elastic connection 3, the crossbar 4, and the flexible guides 20, in particular the elastic flexible blades 6, primary resonators 10, form a monolithic assembly.

Such an embodiment makes it possible to obtain flexible guides 20, in particular so-called "high leaf" elastic blades 6, which have a height that is very large compared to their thickness, in particular at least five times higher than thick, and more particularly at least ten times higher than thick. Such blades in high sheet make it possible to ensure the function of guidance, and to get rid of traditional pivots, which allows a significant increase in the quality factor.

The architecture in the form of a tuning fork, according to the invention, makes it possible to compensate for all the reactions to the recesses, which still considerably increases the quality factor.

In the embodiments illustrated in the figures, the masses 5, 51, 52, primary resonators 10 are essentially subjected to a pivoting movement. The corresponding flexible guide 20, in particular the corresponding flexible flexible blade 6, provides the pivoting guide function.

The invention is illustrated here in variants where, each time, a single elastic flexible blade 6 maintains the respective mass 5 with respect to the crossbar 4. It is possible to imagine other variants where these blades 6 would be doubled or multiplied to ensure even better guidance. However the advantage of the single blade is to work in pure bending, which eliminates shear stresses, or transverse forces, which are unfavorable for isochronism, which explains the preference for a single flexible blade 6, which ensures therefore a better chronometry of a watch incorporating an oscillator 1 according to the invention.

In the case of variants, as illustrated by the figures, wherein each primary resonator 10 is arranged to oscillate in a plane, all the primary resonators 10 are arranged to oscillate in planes parallel to each other, or in the same plane.

More particularly, all these primary resonators 10 are arranged to oscillate in the same plane, for example on the embodiments illustrated in Figures 1 to 12.

In particular embodiments, as visible in Figures 13 to 16, these primary resonators 10 each extend in a separate plane.

It is nonetheless possible to implement the invention with primary resonators arranged differently in space.

FIGS. 1 to 12 illustrate an isochronous oscillator mechanism 1, in which all the primary resonators 10 are identical, in even number, and arranged in symmetry with respect to a plane of symmetry PSY extending parallel to a transverse direction Y which is that of the main elastic connection 3 and perpendicularly to a longitudinal direction X in which are moved the centers of mass CM of the primary resonators 10. Within each pair, the primary resonators 10 then oscillate in phase opposition, which guarantees the compensation of the movements of the centers of mass CM in the longitudinal direction X.

Preferably, the main elastic connection 3 is straight.

On the variants of Figures 1 to 8, according to a first embodiment detailed below, the elastic flexible blades 6 are straight in the longitudinal direction X. The centers of mass CM of the primary resonators 10 are considered in their alignment at rest . This arrangement guarantees insensitivity to the positions of the isochronous oscillator mechanism 1 according to the invention, unlike a tuning fork of the conventional type with parallel branches which is much too sensitive to the positions in space if it is incorporated in a watch, and which can only be suitable for a piece of clock.

The sketches in Figure 2 make it possible to understand the influence of gravity g:

- on the upper sketch, on a first mass suspended upwards by means of a flexible blade, the gait diagram shows a delay of a certain value R,

on the median sketch, on a second identical mass suspended downwards by means of an identical flexible blade, and the gait diagram corresponding to an advance of the same value R,

on the lower sketch, on a mechanism according to the invention which combines the two previous ones, and the corresponding step diagram which shows an advance or a delay close to zero, thanks to the alignment in the opposite direction, which allows a balancing, by averaging the advance / delay of the two resonators that compose it, thus making the mechanism insensitive to positions in space.

The residual defect after compensation of the displacements of the centers of mass in X is of very small value, of the same order of magnitude as the defect due to displacements of the centers of mass in Y, which is limited to 3 or 4 micrometers, for a blade of 1 mm long, the cumulative defect thus remains less than 6 seconds per day.

The compensation due to the geometry of the isochronous oscillator mechanism 1 according to the invention, in particular in a fully symmetrical execution, thus reinforces the character of insensitivity to gravitation due to the operation. The symmetry thus compensates for any residual run error.

In addition, the compensation of forces and torques to the recess allows the primary resonators 10 to oscillate very long without amortizing.

In a particular variant of this first embodiment, the resilient flexible blades 6 that comprise the primary resonators 10 are straight and aligned in pairs.

On the variants of Figures 9 to 12, according to a second embodiment detailed below, the flexible guides 20 are constituted by resilient flexible blades 6 in spirals, wound around the centers of mass CM primary resonators 10 considered.

A variant illustrated in FIGS. 13 and 14 represents a torsion tuning fork which comprises arms 51 and 52, each provided with a mass at its distal end, and oscillating in parallel planes P1 and P2 and symmetrically with respect to a axis A parallel to these two planes P1 and P2.

Another variation of the tuning fork illustrated in FIG. 15 comprises two resonators, each comprising a spiral spring recessed at a first end on a common cross-piece and having a mass at a second distal end, these two resonators extending in two parallel planes and being, in projection on one of these planes, symmetrical with respect to a plane of symmetry PS which is perpendicular to these two planes. The resulting torque is zero at the embedding at the crossbar 4.

It is understood that the invention allows a wide variety of geometric architectures.

The practical difficulties are not lacking, because it is difficult to ensure the limitation in displacement of the centers of mass CM of the primary resonators 10 in the transverse direction Y.

In addition, the mechanisms must be usable in a watch, and incorporate security, including shockproof.

Two particular embodiments, geometrically quite different, but both obeying the logic of the invention, are presented hereinafter: a first tuning fork mode "in H", and a second tuning fork mode "horns goat". The first H-tuned fork mode is shown in FIGS. 1 to 7. The fixed support 2, the main elastic connection 3, the crosspiece 4, and the flexible flexible blades 6 of the primary resonators 10, together form a flat monolithic structure, in silicon, or oxidized silicon, or quartz, or DLC, or the like, which, in the rest position of the isochronous oscillator mechanism 1, is symmetrical with respect to a plane of symmetry PS, and comprises an elongate cross-piece 4 which extends in the longitudinal direction X, perpendicular to the main elastic connection 3, which extends in the transverse direction Y, and which holds the crossbar 4 on the fixed support 2.

This crosspiece 4 carries a pair of marked masses 51 and 52, mounted symmetrically on either side of the fixed support 2 and the first elastic connection 3.

These masses 51, 52, extend substantially in the transverse direction Y, forming the lateral bars of an H whose crossbar 4 constitutes the horizontal bar. Preferably each of them comprises an arm connected in the middle to the corresponding flexible blade 6, this arm extending substantially parallel in the transverse direction Y, and being either a solid arm as in FIG. 3, or an arm comprising inertial flyweights at its opposite ends, either substantially punctual as in Figure 1, or in the form of annular sectors, as visible in Figures 2 and 4 to 7.

Each of these masses 51, 52 is mounted oscillating about a virtual pivoting axis of position determined relative to the crossbar 4, and recalled by an elastic flexible blade 6, respectively marked 61, 62, which constitutes means of resilient return and which is secured to one end 41, 42 of the cross member 4, the two ends 41 and 42 being opposite and on either side of the crossbar 4. These flexible blades 61, 62, extend from preferably linearly in the extension and on both sides of the crossbar 4.

Each virtual pivoting axis is, in the rest position of the isochronous oscillator mechanism 1, coinciding with the center of mass CM1, CM2, of the respective mass 51, 52.

These resilient flexible blades 61, 62, are arranged to limit the displacement of the centers of mass CM1, CM2, to a transverse stroke relative to the crossbar 4, as small as possible in the transverse direction Y, and at a longitudinal stroke in the longitudinal direction X greater than this transverse stroke.

Due to the symmetry and the alignment, the longitudinal arrangement of the resilient flexible blades 61, 62 makes it possible to compensate for the direction of greater displacement of the centers of mass CM1 and CM2, which move symmetrically relative to the plane symmetry PS.

The isochronous oscillator mechanism 1 according to the invention advantageously comprises rotational stops, and / or translational limit stops in the X and Y directions, and / or translation Z limit stops. These stroke limiting means can be integrated, part of a one-piece construction, and / or be reported.

The masses 51, 52, advantageously comprise abutment means 7, labeled 71, 72, which are arranged to cooperate with complementary abutment means 73, 74, which the crosspiece 4 comprises, and to limit the displacement of the elastic flexible blades. 61, 62, with respect to the crossbar 4, in the event of shocks or similar accelerations.

In the case where a mass 5 is not directly carried by the flexible blade 6, the latter comprises, on the other side relative to the main body of the crosspiece 4, an end plate 45, which is arranged to receive, directly or indirectly, this mass 6. For example, the execution of Figures 4 and 5, as the variant of the second embodiment of Figures 1 1 and 12, comprises endpieces 53, 54, arranged to be reported on such a plate end 45 and receive a mass 51 or 52. The variant of the first embodiment of Figures 6 and 7 comprises a sleeve 55 arranged to perform the same function.

In the variant of the first embodiment of FIGS. 4 and 5, the ends of the crossmember 4 each comprise two abutment bearing surfaces 42, each of which is arranged to stop an oblique surface 74 that the end plate 45 comprises, so as to limit the angle of deformation a (defined in Figure 1) that can take the flexible blade 6 relative to its installation in the crossbar 4, and thus constituting stops in rotation. The corresponding end of the crosspiece 4 further comprises a housing 79, in this case a bore, arranged to act as a limit stop around the periphery 48 of the substantially circular end plate 45, to limit X and Y translations. to these different stops, which limit the translations in X and Y, we limit the possible influence of shocks, protects the flexible blade 6, and preserves this flexible blade 6 against excessive deformation. And of course the possible movement of the CM centers of mass is limited.

Z stops are provided mainly when using end caps 53, 54, sockets 55, or the like; for example, FIG. 5 illustrates endpieces 53, 54, which either comprise bores aligned with journals 56 carried by a plate, or comprise bearings aligned with bores of a plate, the bearings thus constituted being non-contact in normal operating mode, and being arranged to take the efforts, especially in Z, in case of shock.

The detail of Figure 6 shows, with regard to the variant with the receipt of a sleeve 55, a similar arrangement with respect to the stops. The end plate 45 further comprises a lug with stop surfaces 76 arranged to cooperate abutting abutment with complementary surfaces 78 of the cross member 4, to limit the translations. The bushing 55 has a skirt 57 driven on the end plate 45, but the periphery 59 of this bushing 55 remains at a distance from the bore 79 of the cross member 4, and thus ensures with it the safety in translation in X and in Y .

Z-shaped shoulders may also be provided on certain surfaces to form Z-limiting abutment surfaces.

Naturally, these arrangements of abutment, limiting the travel of the flexible blade 6 as shockproof are feasible in variants without intermediate part. And in particular in the case where the fixed support 2, the main elastic connection 3, the crossbar 4, and the primary resonators 10, including the masses 5, form a monolithic assembly.

In the absence of unexpected accelerations such as shocks, the complementary surfaces of the stops must not be in contact with each other, so as to avoid any unnecessary friction detrimental to the quality factor.

Some stroke limiting means may be used to perform damping functions of unwanted vibration modes.

The illustrations of the first and second embodiments thus show the fixed support 2 and the crossbar 4 which are separated only by a narrow groove 30, here called "honey groove", around the main elastic connection 3, which is designed to allow coupling in tuning fork mode. The groove 30 allows to limit the angular movement of the crossbar 4, which is insignificant in normal regime, but can occur in case of shock. Advantageously, this groove is filled with a viscous or pasty product, which allows the dissipation of energy in the event of excessive travel.

In particular, it is a question of preventing, or at least of limiting, the duration of a "windshield wiper" mode of operation in which the primary resonators 10 oscillate, no longer in phase opposition, but in phase because it is understood that the compensation of the movements of the centers of mass is then no longer ensured in this phase oscillation regime, which no longer allows the oscillator to be isochronous.

Alternatively, or in addition, it is possible to add cooperating Z surfaces with a solid friction, or viscous, or pasty, and preferably increasing with the speed and / or with the amplitude, for example with conical surfaces or corner, as shown in the sketches of Figures 17 and 18.

Preferably, the elastic flexible blades 61, 62, which extend substantially in the longitudinal direction X, are short blades, that is to say a length less than the smallest value between four times their height or thirty times their thickness. It is this short blade characteristic that makes it possible to limit the movements of the center of mass CM concerned.

In normal operation, there is no friction. The modes of oscillation in translation, and displacements in case of shocks are mechanically limited by axes or the like.

In this configuration, the center of mass CM of each primary resonator 10 does not move substantially in the transverse direction Y: it performs a crawling movement, on either side of an average axis parallel to the longitudinal direction X, around from a point on this mean axis.

It is to compensate for this displacement of the center of mass CM along X that, according to the invention, the resilient flexible blades 61 and 62 are preferably aligned, these blades being preferably straight.

The second mode of tuning horn fork is shown in Figures 8 to 12. The fixed support 2, the main elastic connection 3, the crossbar 4, the flexible flexible blades 6, and the end plates 45 of the primary resonators 10 , together form a planar monolithic structure, made of silicon, or oxidized silicon, or quartz, or DLC, or the like, which, in the rest position of the isochronous oscillator mechanism 1, is symmetrical with respect to a plane of symmetry PS, and comprises an elongate cross member 4 extending in the longitudinal direction X, perpendicular to the main elastic connection 3, which extends in the transverse direction Y, and which holds the crossbar 4 on the fixed support 2.

In a similar manner to the first mode, this crosspiece 4 carries a pair of marked masses 51 and 52, mounted symmetrically on either side of the fixed support 2 and the first elastic connection 3. Each of these masses 51, 52 is mounted oscillatingly and biased by an elastic flexible blade 6 respectively marked 61, 62, which is a spiral 8, respectively 81, 82, or a spiral assembly. A first hairspring 81 and a second hairspring 82 are each bonded at its inner turn to an end plate 45 for receiving a mass 51, 52, and attached to the respective end 41, 42 of the sleeper 4. by its external turn.

The masses 51 and 52 each pivot about a virtual pivot axis of position determined relative to the crossbar 4.

In the same way as for the first mode, the masses 51, 52, extend substantially in the transverse direction Y. Preferably each of them comprises an arm connected in its middle to the corresponding flexible blade 6, this arm s' extending substantially parallel in the transverse direction Y, and being either a solid arm as in FIG. 3, or an arm having inertial flyweights at its opposite ends, or substantially pointwise as in FIG. 8, or in the form of annular sectors, as shown in FIGS. 9 to 12.

To limit the displacement of the centers of mass CM1, CM2, to a transverse stroke relative to the crossbar 4, as small as possible in the transverse direction Y, and to a longitudinal stroke in the longitudinal direction X greater than this transverse stroke, each spiral 81, 82, is section or variable curvature along its development.

The version illustrated by the figures is a variation of variable thickness, optimized to limit the movements of the center of mass CM. The mass 5 pendulum is preferably suspended by a coil thicker than the rest of the spiral.

Preferably, the development of the hairspring is greater than one turn, and in particular greater than 1.5 turns, which is easier to minimize the displacement of the center of mass. For example, a regular decrease in thickness over 270 °, followed by growth in thickness may make it possible to limit the displacement of the center of mass CM to 3 micrometers in Y and 4 micrometers in X. The polar elemental stiffness advantageously passes through an extremum, for example a mini between two maxi, or the opposite.

A satisfactory simulation consists, again, in giving the hairspring an upper stiffness in its portion 89 which is beyond the center of mass towards the outside, than in its portion 88 which lies between the two centers of mass CM1 and CM2.

It can thus be seen that the X-displacements of the centers of mass CM are smaller in this second spiral mode than in the first mode with a straight blade.

One can, of course, play on the height instead of the thickness to obtain a variable section: the choice of the variable thickness corresponds to an elaboration MEMS easier.

In sum, we can make an analogy between this spiral with variable characteristics and a Breguet or Grossmann end curve of a spiral balance-balance spiral.

Once the displacement of the center of mass has been minimized, the symmetrical assembly with respect to the plane of symmetry PS makes it possible to obtain an excellent isochronism.

In normal operation, there is no friction: The modes of oscillation in translation and the displacements in the event of shocks are preferably mechanically limited by axes, or by end pieces 53, 54, or sockets 55.

Preferably, the first hairspring 81 and the second hairspring 82 are attached to the ends 41, 42, in alignment with their respective virtual pivoting axis, in the rest position of the isochronous oscillator mechanism 1.

FIG. 16 illustrates another embodiment close to the invention, in which this figure diagram of the second mode is extrapolated by suspending each mass, not to a single spiral, but pairs of spirals 81, 810, respectively 82, 820, attached to the cross member 4, on either side of the centers of mass in the Y direction. This very robust embodiment is however closer of a system with crossed flexible blades that the principle of the present invention.

FIG. 19 illustrates a variant where the cross member 4 constitutes a frame surrounding the primary resonators 10, in one example of application to four resonators 10A, 10B, 10C, 10D. It is understood that this inverse architecture of the previous examples is also usable for the implementation of the invention, in all its variants described above, and which are therefore not detailed further here.

FIG. 20 illustrates, in this variant of crossbar 4 formed by a frame, the pendant of the tuning fork H. The crossbar 4 carries a pair 51, 52, of masses 5, mounted symmetrically inside the crossbar 4 which form a frame suspended by the first elastic connection 3 to the fixed structure 2, the masses 51, 52 extending substantially in the transverse direction Y. Each of the masses 51, 52, is mounted oscillating about a pivot axis virtual position determined with respect to the crossbar 4, and recalled by a resilient flexible blade 6, respectively 61, 62, which is integral with one side of the frame forming the crossbar 4, the flexible blades 61, 62, extending linearly inside the frame.

In a similar manner, FIG. 21 illustrates, in this variant of crossbar 4 formed by a frame, the pendulum of the goat horn fork. The crossbar 4 carries a pair 51, 52, masses 5, mounted symmetrically inside the crossbar 4 which forms a frame suspended by the first elastic connection 3 to the fixed structure 2, and substantially in a transverse direction Y perpendicular to the longitudinal direction X in which the centers of mass CM of the primary resonators 10 are movable. Each of the masses 51, 52 is oscillatingly mounted about a virtual pivot axis of position determined with respect to the crossbar 4, and recalled by a spiral 8, respectively 81, 82, which is integral with one side of the frame forming the crossbar 4, these spirals 81, 82, extending inside the frame.

In the illustrated embodiments the masses 5, 5A, 5B, 51, 52, form rockers.

Advantageously, in any embodiment, the masses 51, 52 comprise, for balancing adjustment, inertia and adjustment of frequency of oscillation, flyweights 91, 92, and / or housings 93 for receiving such flyweights, preferably in the areas furthest from the ends 41, 42 of the crossbar 4. Such flyweights advantageously comprise an eccentric insert, for example in platinum, to facilitate adjustment by pivoting the insert. Naturally, particular areas of these masses may be assigned to laser ablation, or, conversely, to plasma, ink jet or the like, to provide these settings.

The invention also relates to a clockwork movement 100, in particular a mechanical movement, comprising such an isochronous oscillator mechanism 1.

The invention also relates to a watch 200 comprising such a mechanical movement 100.

In sum, in its totally symmetrical version, the oscillator according to the invention constitutes a tuning fork composed of two resonators, preferably rotary, with flexion blades, mounted on a cross member connected, preferably viscoelastically, to the plate.

The elastic members of each primary resonator 10 are designed to minimize the displacement of the center of mass CM in the transverse direction Y of the symmetry plane PSY of the tuning fork.

The plane of symmetry PSY of the tuning fork is chosen so that the operating errors due to the positions in the longitudinal direction X perpendicular to the transverse direction Y, are canceled between the two branches of the tuning fork constituted by the primary resonators 10, both sides of the crossbar 4.

The use of rotating primary resonators makes it possible to limit the effect of translational accelerations (shocks and orientation in the gravitational field) on the resonator rhythm.

The architecture of tuning fork type limits the effect of reactions to embedding.

To make the movement of the watch insensitive to positions, the invention minimizes the displacement of the center of mass CM of each primary resonator 10.

For the second embodiment of the invention known as goat horn tuning fork, the advantages are:

blades in pure flexion, hence isochronism; architecture of the tuning fork type, therefore zero reactions to embedding, and therefore a better quality factor;

the elastic element constituted by the flexible blade also acts as a guide, so there is no need for pivots, so there is no friction, and so we get a better quality factor;

blade thickness in the form of a turn variable and optimized to limit parasitic movements of the center of mass in the Y direction, resulting in a low error of walking in the vertical position of the watch:

blades oriented so that the residual error of operation (due to the vertical positions in the longitudinal direction X) is canceled between the two blades of the tuning fork;

limitation of integrated strokes, which provides great strength, and prevents the blades from breaking in the event of shocks in X, Y, Z, or a;

Honey groove, allowing a damping of the oscillation mode in "wiper" likely to occur during an impact.

For the first embodiment of the invention known as the H-tuning fork, the main characteristics are similar, except for:

minimized blade length to limit parasitic shifts of the center of mass in the X and Y directions, thus providing a low error in the vertical position

rectilinear flexible blades oriented along an axis perpendicular to the plane of symmetry of the tuning fork, so that the error due to the vertical positions in the longitudinal direction X, which is greater than the error in the transverse direction Y in this case, is canceled between the two blades of the tuning fork.

In summary, the invention makes it possible to obtain a perfectly isochronous oscillator, very compact, requiring no adjustment other than the inertia of the masses, and very easy assembly.

Claims

R EVE NDI CATI ON S

1. Isochronous oscillator mechanism (1) with a fixed support (2) which carries a cross member (4) carrying a plurality of N primary resonators (10) each comprising at least one mass (5) carried by a flexible guide rotary device (20) fixed to said crossbar (4), characterized in that each said primary resonator (10) has a center of mass (CM) which is located, at rest, on the virtual pivot axis (APV) of its said respective rotary guide (20), and in that each said primary resonator (10) is arranged to oscillate in a rotational movement about said virtual pivot axis (PVA), in that said N primary resonators (10) are arranged in a rotation symmetry of order N about a principal axis (AP) which is parallel to all said virtual pivot axes (APV) which are parallel to each other, and in that the oscillation movements of two so-called primary resonators (10) of said oscillating mechanism (1) are out of phase with the value of the center angle of their respective virtual pivot axes (APVs) relative to said main axis (AP).

2. Isochronous oscillator mechanism (1) according to claim 1, characterized in that each said flexible rotary guide (20) is, in projection on a plane perpendicular to said main axis (AP), symmetrical with respect to a plane of symmetry (PS ) passing through said virtual pivot axis (APV) of said rotating flexible guide (20).

3. Isochronous oscillator mechanism (1) according to claim 2, characterized in that each said plane of symmetry (PS) passes through said main axis (AP).

4. Isochronous oscillator mechanism (1) according to one of claims 1 to 3, characterized in that each said flexible rotary guide (20) is arranged to cause a return torque proportional to the angle of rotation of said at least one mass (5) relative to said virtual pivot axis (APV) of said rotary flexible guide (20).

5. Isochronous oscillator mechanism (1) according to one of claims 1 to 4, characterized in that said primary resonators (10) have at least one identical resonance mode.

6. Isochronous oscillator mechanism (1) according to one of claims 1 to 5, characterized in that all said primary resonators (10) are identical to each other.

7. Isochronous oscillator mechanism (1) according to one of claims 1 to 6, characterized in that said crossbar (4) is fixed to said fixed support (2) by a main elastic connection (3), whose rigidity is greater than the rigidity of each said rotating flexible guide (20)

Isochronous oscillator mechanism (1) according to one of claims 1 to 7, characterized in that each said primary resonator (10) is arranged to oscillate in a plane about a neutral radial axis (AN) and that all said neutral radial axes (AN) are concurrent at a single point or concurrently two by two at meeting points all located at the same distance from said main axis (AP).

9. isochronous oscillator mechanism (1) according to claim 8, characterized in that said primary resonators (10) are in an even number or two in number, and in that all said neutral axes (AN) are, two by two, parallel to each other or confused.

Isochronous oscillator mechanism (1) according to one of claims 1 to 9, characterized in that said flexible guide (20) comprises at least one elastic flexible blade (6) and in that said virtual pivot axis (APV) is in the middle of said elastic flexible blade (6).

1 1. Isochronous oscillator mechanism (1) according to one of claims 1 to 9, characterized in that said flexible guide (20) comprises at least crossed blades, which are or are crossed in the same plane, or whose projections on a plane perpendicular to said main axis (AP) are crossed, and whose actual intersection or projection on said plane perpendicular to said main axis (AP) defines said virtual pivot axis (APV) of said flexible guide (20).

Isochronous oscillator mechanism (1) according to one of claims 1 to 9, characterized in that said flexible guide (20) comprises at least one neck with necking section.

13. Isochronous oscillator mechanism (1) according to one of claims 1 to 9, characterized in that said primary resonators (10) are in an even number or two in number, and in that said flexible guide (20) of each said primary resonator comprises at least one hairspring, said coils of said primary resonators (10) being arranged in pairs.

14. Isochronous oscillator mechanism (1) according to one of claims 1 to 13, characterized in that at least said flexible guide (20) is made of micro-machinable material, or silicon and / or silicon oxide, or quartz, or DLC.

15. Isochronous oscillator mechanism (1) according to one of claims 1 to 14, characterized in that each said primary resonator (10) comprises thermal compensation means at least at said flexible guide (20).

16. Isochronous oscillator mechanism (1) according to claim 15, characterized in that said thermal compensation means comprise at least one component made of élinvar or silicon and silicon oxide.

17. Isochronous oscillator mechanism (1) according to one of claims 1 to 16, characterized in that at least one said primary resonator (10) comprises louvre limiting means arranged to cooperate in the event of impact abutment abutment with additional means of frost limitation, that includes said structure (2) and / or said crossbar (4).

18. Isochronous oscillator mechanism (1) according to one of claims 1 to 17, characterized in that at least two said primary resonators (10) are coupled to each other, at least intermittently, by a wheel exhaust.

19. Isochronous oscillator mechanism (1) according to one of claims 1 to 18, characterized in that said primary resonators (10) are arranged to oscillate each at a frequency between 1 Hz and 100 Hz.

20. Watchmaking movement (100) comprising at least one isochronous oscillator mechanism (1) according to one of claims 1 to 19.

21. Watch (200) comprising at least one movement (100) according to the preceding claim.