EP3206089A1 - Timepiece resonator mechanism - Google Patents

Abstract

Clock resonator mechanism (1000) comprising two flexible RCC pivots (10A, 10P) connected in series around an intermediate rotary support (20) and having the same virtual pivot axis (A), each having two straight flexible blades ( 110, 210, 310, 410) of the same length (L), and whose recesses opposite said pivot axis (A) have the same distance (D) with respect to the latter, and defining linear directions (D1, D2, D3, D4), forming two by two angles with said virtual pivot axis (A) at the intersection, whose value expressed in degrees is between: In a variant this clock resonator mechanism (1000) is monoblock in silicon, thermally compensated. Movement (2000) comprising such a clock resonator mechanism (1000). Watch (3000) with such a movement (2000).

Description

Field of the invention

The invention relates to a timepiece resonator mechanism comprising a first support with a first anchor and a second anchor to which is fixed a flexible pivoting guide mechanism, which defines a virtual pivot axis about which rotates a pivoting mass, and which comprises at least one anterior RCC flexible pivot and a posterior RCC flexible pivot mounted in series and head to tail with respect to each other about said virtual pivot axis, said prior RCC flexible pivot comprising, between said first support and an intermediate rotatable support, two straight anterior flexible blades of the same anterior length between their recesses, defining two anterior linear directions which intersect at said virtual pivot axis and which define with said virtual pivot axis an anterior angle, and whose respective anchorages of said two most straight forward flexible blades away from said virtual pivot axis are both at the same previous distance from said virtual pivot axis, and said posterior flexible pivot RCC having, between said intermediate rotary support, which comprises a third anchor and a fourth anchor, and said pivoting mass, two straight posterior flexible blades having the same posterior length between their recesses, defining two posterior linear directions which intersect at said virtual pivot axis and which define with said virtual pivoting axis a posterior angle, and whose respective anchors of said two posterior flexible blades Straightest furthest from said virtual pivot axis are both at the same posterior distance from said virtual pivot axis.

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

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

The invention relates to the field of clock resonator mechanisms.

Background of the invention

It is known that the use of a flexible guiding pivot makes it possible to replace the real pivot of a balance and the spiral spring of elastic return. This has the advantage of eliminating the friction of pivots. However, the flexible guide pins are known to have a non-linear elastic restoring force which makes the resonator anisochronous, that is to say that the frequency depends on the amplitude of the oscillation, and to have a movement parasite of the instantaneous axis of rotation, which makes the movement of the resonator sensitive to its position in the field of gravity.

The problem of the non-linearity of the elastic return force is difficult to solve, and the existing geometric solutions, to improve the linearity of the elastic restoring force and therefore make the isochronous resonator for a given range of angular amplitude, require manufacturing on several levels. The patent application CH01979 / 14 , on behalf of The Swatch Group Research & Development Ltd., incorporated herein by reference, thus discloses a cross-blade clock resonator in two superimposed planes and outlines the importance of the value of a particular angle, to optimize the linearity of the elastic return force and therefore make the resonator isochronous for a given range of angular amplitude. However, such a pivot with flexible guidance can not be engraved at once in 2D, which complicates its manufacture.

Summary of the invention

The invention proposes to produce a mechanical resonator with a high quality factor using an inertial part such as a rocker, supported by a guide with flexible blades in rotation, also called flexible guide pin, which also acts as a means of elastic return. It is desired that this resonator is isochronous (independent of amplitude) and insensitive to positions in the gravitational field (position independent).

The invention seeks to combine the advantages of two known two-dimensional and three-dimensional geometries, in a simple and economical, therefore two-dimensional, execution.

The invention thus relates to a clock resonator mechanism according to claim 1.

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

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

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en vue en perspective, un résonateur mécanique selon l'invention, comportant, entre un premier support agencé pour être fixé directement ou indirectement à la structure d'un mouvement d'horlogerie, et une masse pivotante mobile sur laquelle un rapporté un balancier à bras, deux pivots flexibles RCC montés en série, et tête-bêche, autour d'un support rotatif intermédiaire et de même axe de pivotement virtuel, et comportant chacun deux lames flexibles droites, avec le centre de masse de l'ensemble constitué par la masse pivotante mobile et le balancier rapporté coïncidant avec l'axe de pivotement virtuel;
• la figure 2 est une variante où le balancier rapporté comporte une serge circulaire ;
• la figure 3 représente, de façon schématisée et en vue en plan, la partie centrale du résonateur de la figure 1 ;
• la figure 4 est un détail de la même partie centrale, mettant en évidence les différentes surfaces de limitation pour la protection anti-chocs, que comporte ce résonateur ;
• la figure 5 est un graphique représentant la valeur optimale de l'angle entre les deux lames de chaque pivot flexible RCC, en fonction du ratio entre, d'une part la distance de l'encastrement d'une lame, opposé à l'axe de pivotement, et d'autre part avec la longueur de la lame concernée ;
• les figures 6 à 8 illustrent d'autres variantes d'arrangements géométriques;
• la figure 9 est un schéma-blocs représentant une montre avec un mouvement incorporant un résonateur selon l'invention, lequel comporte plusieurs mécanismes flexibles de guidage en pivotement disposés en série.

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

• the figure 1 represents schematically and in perspective view, a mechanical resonator according to the invention, comprising, between a first support arranged to be fixed directly or indirectly to the structure of a watch movement, and a mobile pivoting mass on which a rocker arm, two flexible pivots RCC mounted in series, and head-to-tail, around an intermediate rotary support and the same virtual pivot axis, and each having two straight flexible blades, with the center of mass of the assembly consisting of the mobile pivoting mass and the reported balance coinciding with the virtual pivot axis;
• the figure 2 is a variant where the reported balance has a circular serge;
• the figure 3 represents schematically and in plan view, the central part of the resonator of the figure 1 ;
• the figure 4 is a detail of the same central part, highlighting the different limiting surfaces for the impact protection, that includes this resonator;
• the figure 5 is a graph representing the optimum value of the angle between the two blades of each flexible pivot RCC, as a function of the ratio between, on the one hand, the distance of the embedding of a blade, opposite to the axis of pivoting, and on the other hand with the length of the blade concerned;
• the Figures 6 to 8 illustrate other variations of geometric arrangements;
• the figure 9 is a block diagram showing a watch with a movement incorporating a resonator according to the invention, which comprises a plurality of flexible pivot guide mechanisms arranged in series.

Detailed Description of the Preferred Embodiments

The invention relates to a timepiece resonator mechanism 1000, comprising a first rigid support 100, fixed or mobile, with a first anchor 1 and a second anchor 2, to which is fixed a flexible pivoting guide mechanism 10, which defines a virtual pivot axis A, about which rotates a rigid pivoting mass 200 rotatively.

This flexible pivot guide mechanism 10 is a 2D flexible guide pivot, that is to say, achievable in a plane.

This flexible pivoting guide mechanism 10 allows the rigid pivoting mass 200 to rotate the virtual pivot axis A relative to the first rigid support 100. It is composed of two flexible pivots RCC (Remote Center Compliance, that is to say, center of rotation offset) whose axes of rotation coincide and which are connected by a rigid intermediate rotating support 20. The two RCC pivots are thus put in series, but head to tail with respect to each other, so that their parasitic movements compensate each other.

It will be understood that the recesses close to the virtual pivot axis A of the first pivot RCC are rigidly connected, by the intermediate rotary support 20, to the recesses distant from the virtual pivot axis A of the second pivot RCC, or vice versa, as visible on the Figures 6 and 7 .

Thus, the flexible pivotal guide mechanism 10 includes an earlier RCC flexible pivot 10A and a rearward flexible RCC pivot 10P, which are connected in series with each other, and head-to-tail, about the pivot axis virtual A common, and which incorporate elastic flexible elements.

The front flexible pivot RCC 10A comprises, between the first support 100 and an intermediate rotary support 20, two anterior resilient assemblies 11, 21, formed, in the embodiment of the figures, by two straight forward flexible blades 110, 210, and the like. anterior length LA between their recesses, defining two linear previous directions D1, D2, which intersect at the virtual pivot axis A, and which define with this virtual pivot axis A at an anterior angle αA, and whose respective anchors of the two right anterior flexible blades 110, 210, the farthest from the virtual pivot axis A are both at the same distance anterior DA of the virtual pivot axis A.

Similarly, the rear flexible pivot RCC 10P comprises, between the intermediate rotary support 20, which comprises a third anchorage 3 and a fourth anchorage 4, and the pivoting mass 200, two rear elastic assemblies 31, 41, formed in the embodiment of the figures, by two right posterior flexible blades 310, 410 having the same posterior length LP between their recesses, defining two posterior linear directions D3, D4, which intersect at the level of the virtual pivot axis A, and which define with this virtual pivot axis A a αP posterior angle, and whose respective anchors of the two posterior flexible blades straight 310, 410, the farthest from the virtual pivot axis A are both at the same rear distance DP of the virtual pivot axis A.

In addition, the flexible pivoting guide mechanism 10 is planar.

The invention consists in optimizing the angle between the elastic elements of each flexible pivot RCC, so that the pivot has a linear elastic return force, so that the mechanical resonator is isochronous in a given range of angular amplitude.

• l'angle antérieur αA exprimé en degrés est compris entre :
  109.5 + 5/[(DA/LA)-(2/3)] et 114.5 + 5/[(DA/LA)-(2/3)],
• et l'angle postérieur αP exprimé en degrés est compris entre :
  109.5 + 5/[(DP/LP)-(2/3)] et 114.5 + 5/[(DP/LP)-(2/3)].

According to the invention, the center of inertia of the assembly formed by the pivoting mass 200 and any reported inertial mass 201 carried by the pivoting mass 200, as in the non-limiting variants illustrated in FIGS. Figures 1 and 2 , is on the virtual pivot axis A or in its immediate vicinity, and the mechanical resonator is isochronous if:

• the previous angle αA expressed in degrees is between:
  109.5 + 5 / [(DA / LA) - (2/3)] and 114.5 + 5 / [(DA / LA) - (2/3)],
• and the posterior angle αP expressed in degrees is between:
  109.5 + 5 / [(DP / LP) - (2/3)] and 114.5 + 5 / [(DP / LP) - (2/3)].

In a particular variant, the front angle αA and the posterior angle αP are equal to a common angle α. More particularly, this common angle α is close to 112.0 °.

In a preferred variant, the anterior distance DA and the posterior distance DP are equal to a common distance D, and the anterior length LA and the posterior length LP are equal to a common length L. The common angle α is then between: $$\mathrm{109.5}+\mathrm{5}/\left[\left(\mathrm{D}/\mathrm{The}\right)-\left(\mathrm{2}/\mathrm{3}\right)\right]\mathrm{and}\mathrm{114.5}+\mathrm{5}/\left[\left(\mathrm{D}/\mathrm{The}\right)-\left(\mathrm{2}/\mathrm{3}\right)\right]\mathrm{.}$$

The figure 5 shows the evolution of the optimal angle α, as a function of the D / L ratio.

More particularly, and as visible in the figures, the first anterior elastic assembly 11, the second anterior elastic assembly 21, the first posterior elastic assembly 31, and the second posterior elastic assembly 41 each comprise at least one straight flexible blade 110, 210, 310, 410, or a bundle of parallel straight flexible blades, not shown to avoid complicating the figures.

More particularly, in the variants illustrated in the figures, the first anterior elastic assembly 11, the second anterior elastic assembly 21, the first posterior elastic assembly 31, and the second posterior elastic assembly 41 each consist of a straight flexible blade 110,210,310,410.

In another variant not illustrated in the figures, the first anterior elastic assembly 11, the second anterior elastic assembly 21, the first posterior elastic assembly 31, and the second posterior elastic assembly 41 each comprise an alternation of straight flexible blades and elements. intermediates more rigid than these straight flexible blades, aligned in the respective directions D1, D2, D3, D4.

In order to obtain a mechanical resonator with a high quality factor, it is advantageous to relate an inertial element 201 to the pivoting mass 200, or to integrate it therewith, and to fix the first rigid support 100 to a plate or a bridge of the watch movement, or any other element that can act as a support for the flexible pivot resonator, for example, without limitation, a tuning element of a tuning fork, or an anti-shock element which is authorized to move only in the event of a violent impact, so as to reduce the acceleration experienced by the resonator. Of course, the fixed part and the moving part represented here are permutable. This inertial element can be a disk, a ring such as a beam serge as visible on the figure 2 , or a simple arm as visible on the figure 1 . It is important that the center of mass of the inertial element is substantially aligned with the virtual pivot axis A.

To avoid undesirable eigenmodes, it is advantageous to skeleton the rigid intermediate rotary support 20 with recesses 209, so as to reduce its inertia, while giving it a rigidity much greater than that of the flexible blades constituting the elastic assemblies 11, 21 , 31, and 41, as visible on the Figures 1 to 4 .

In the same way, when the elastic elements comprise intermediate elements that are stiffer than the straight flexible blades, these intermediate elements are advantageously also skeletonized.

Another advantageous variant, concerning all the embodiments, consists of arranging the rigid parts 100, 20, 200, very close to each other around the virtual pivot axis A, so that they act as anti-shock, radial or / and angular abutments, in order to prevent a rupture of the blades, as visible with the surfaces 105, 25, 26, 206, 28, 208, of the figure 4 , in particular the oblique faces 28 and 208 which contribute greatly to the impact resistance of the system. Or to equip some of the rigid parts with limiting arms 27 arranged to cooperate in abutment, in case of impact, with complementary surfaces 107 that includes the first support 100, as visible on the figure 4 where the intermediate rotary support 20 carries such limiting arms 27.

Preferably, the arrangement of the most rigid parts comprises limiting surfaces 101, 102, 203, 204 arranged to limit the flexible blades, as visible on the figure 4 .

The invention can be implemented with blades having other geometries, for example in zig-zag or serpentine or with curved parts, but it is clear that the geometry of straight blades strongly limits the possible parasitic displacements of the virtual pivot axis A, and remains the most advantageous mode of implementation of the invention.

The blades may, again, have varying thicknesses.

The essential thing is to respect the symmetry of flexibility with respect to the bisector of the angle αA, and with respect to the virtual pivot axis A.

The invention is particularly well suited to monolithic execution.

In an advantageous embodiment, the first support 100, the pivoting mass 200, and the flexible pivoting guide mechanism 10 form a one-piece assembly. This one-piece assembly can be produced either by conventional machining, or else, in a particular and non-exhaustive manner, by "MEMS" or "LIGA" type technologies or 3D printing or additive manufacturing by laser or the like, in silicon, quartz , DLC, metal alloys, glass, ruby, sapphire or other ceramic, or polymers, whether charged or not, or the like, thermally compensated, in particular by particular local growth of silicon dioxide, in certain areas of the room arranged for this purpose, when this one-piece assembly is made of silicon. Naturally, other materials are usable, for some at the cost of temperature compensation. Mention may be made in particular, and not exclusively, of amorphous or crystalline metal alloys.

When the pivoting mass 200 carries a reported inertial mass 201, the flexible pivoting guide mechanism 10 is advantageously made of silicon, oxidized in such a way that the complete resonator mechanism 1000, with this reported inertial mass 201, is thermally compensated.

The clock resonator mechanism 1000 may comprise a plurality of such flexible pivoting guide mechanisms 10 connected in series, to increase the total angular travel, arranged in parallel planes, and around the same virtual pivot axis A, by joining together rigid parts between them. Such a part can be formed by assembling two pieces engraved on one level, or can be etched in silicon SOI two levels.

It is advantageous to use two flexible pivot steering mechanisms in tuning fork configuration, to eliminate the reaction to the support; this is generalizable to a number N of flexible pivoting guide mechanisms.

The invention also relates to a 2000 clockwork movement comprising at least one such resonator mechanism 1000.

The invention also relates to a watch 3000 comprising at least one such movement 2000.

• bon isochronisme, marche indépendante des positions dans le champ de gravité, marche indépendante de l'amplitude;
• facilité de fabrication, grâce au regroupement des éléments fonctionnels dans un seul plan, réalisable en deux dimensions, par gravure en une seule fois dans du silicium ou similaire, ou bien par découpage dans une plaque, par électro-érosion, laser, jet d'eau, fabrication additive ou autre

The invention provides several advantages:

• good isochronism, independent walking of positions in the gravity field, independent of amplitude;
• ease of manufacture, thanks to the grouping of the functional elements in a single plane, feasible in two dimensions, by one-time etching in silicon or the like, or by cutting into a plate, by electro-erosion, laser, jet of water, additive manufacturing or other

Claims (13)

Clock resonator mechanism (1000) comprising a first support (100) with a first anchor (1) and a second anchor (2) to which is fixed a flexible pivoting guide mechanism (10), which defines a virtual pivot axis (A) rotatably pivotally pivoting thereagainst (200), and having at least one anterior RCC flexible pivot (10A) and a rearwardly flexible RCC pivot (10P) connected in series and head to tail relative to one another at the other around said virtual pivot axis (A),
said anterior RCC flexible pivot (10A) having, between said first support (100) and an intermediate rotatable support (20), two straight forward flexible blades (110, 210) of the same anterior length (LA) between their recesses, defining two directions linear lines (D1, D2) which intersect at said virtual pivot axis (A) and which define with said virtual pivot axis (A) an anterior angle (αA), and whose respective anchors of said two anterior flexible blades straight (110, 210) furthest from said virtual pivot axis (A) are both at the same previous distance (DA) from said virtual pivot axis (A),
and said posterior flexible RCC pivot (10P) having, between said intermediate rotary support (20), which comprises a third anchorage (3) and a fourth anchorage (4), and said pivoting mass (200), two straight rear flexible blades ( 310, 410) of the same posterior length (LP) between their recesses, defining two posterior linear directions (D3, D4) which intersect at said virtual pivot axis (A) and which define with said virtual pivot axis (A) a posterior angle (αP), and whose respective anchors of said two right posterior flexible blades (310, 410) furthest from said virtual pivot axis (A) are both at the same posterior distance (DP) of said virtual pivot axis (AT),
characterized in that said flexible pivoting guide mechanism (10) is plane, in that the center of mass of the assembly formed by said pivoting mass (200) and any reported inertial mass (201) carried by said pivoting mass (200) is on said virtual pivot axis (A) or in its immediate vicinity, in that said anterior angle (αA) expressed in degrees is between: $$\mathrm{109.5}+\mathrm{5}/\left[\left(\mathrm{DA}/\mathrm{THE}\right)-\left(\mathrm{2}/\mathrm{3}\right)\right]\mathrm{and}\mathrm{114.5}+\mathrm{5}/\left[\left(\mathrm{DA}/\mathrm{THE}\right)-\left(\mathrm{2}/\mathrm{3}\right)\right]$$

and in that said posterior angle (αP) expressed in degrees is between: $$\mathrm{109.5}+\mathrm{5}/\left[\left(\mathrm{DP}/\mathrm{LP}\right)-\left(\mathrm{2}/\mathrm{3}\right)\right]\mathrm{and}\mathrm{114.5}+\mathrm{5}/\left[\left(\mathrm{DP}/\mathrm{LP}\right)-\left(\mathrm{2}/\mathrm{3}\right)\right]\mathrm{.}$$

Clock resonator mechanism (1000) according to claim 1, characterized in that said anterior angle (αA) and said posterior angle (αP) are equal. Clock resonator mechanism (1000) according to claim 2 or 3, characterized in that said anterior length (LA) and said posterior length (LP) are equal to a common length (L), and in that said anterior distance ( DA) and said posterior distance (DP) are equal to a common distance (D). Clock resonator mechanism (1000) according to claim 2, characterized in that said anterior angle (αA) and said posterior angle (αP) are equal. at a common angle α, expressed in degrees, which is equal to 112.0 ° + 5 / [(D / L) - (2/3)]. Clockwork resonator mechanism (1000) according to one of claims 1 to 4, characterized in that said intermediate rotary support (20) is skeletonized by recesses (209) to minimize its mass and avoid undesirable eigen modes. Clock resonator mechanism (1000) according to one of claims 1 to 5, characterized in that said first support (100), said pivoting mass (200), and said flexible pivoting guide mechanism (10) are arranged very close to each other about said virtual pivot axis (A) and comprise surfaces (105, 25, 26, 206) constituting anti-shock abutments to prevent a rupture of said flexible blades (11, 21, 31, 41). Clock resonator mechanism (1000) according to claim 6, characterized in that said intermediate rotary support (20) comprises limiting arms (27) arranged to cooperate in abutment in the event of impact with complementary surfaces (107) that comprises said first support (100). Clock resonator mechanism (1000) according to one of claims 1 to 7, characterized in that said first support (100), said pivoting mass (200), and said flexible pivoting guide mechanism (10) form an assembly piece. Clock resonator mechanism (1000) according to claim 8, characterized in that said one-piece assembly is made of silicon, thermally compensated. Clock resonator mechanism (1000) according to claim 8, characterized in that said pivoting mass (200) carries an attached inertial mass (201), and in that said flexible pivoting guide mechanism (10) is made of silicon, oxidized so that said resonator mechanism (1000) complete with said reported inertial mass (201) is thermally compensated. Clock resonator mechanism (1000) according to one of claims 1 to 10, characterized in that it comprises a plurality of said flexible pivoting guide mechanisms (10) connected in series, to increase the total angular travel, arranged in parallel planes, and around the same said virtual pivot axis (A). Watchmaking movement (2000) comprising at least one clock resonator mechanism (1000) according to one of Claims 1 to 11. Watch (3000) comprising at least one movement (2000) according to claim 12.

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