EP3382472A1 - Guide bearing of a timepiece balance pivot - Google Patents

Abstract

Bearing (1a) for guiding an axis of a timepiece shaft, in particular a guide bearing for a shaft portion of a timepiece resonator, comprising at least one support element (13a) arranged to exert an action on the shaft, permanently radially to the axis or substantially radially to the axis.

Description

The invention relates to a rotational guide bearing for a timepiece shaft, in particular a guide bearing for a shaft portion or a pivot of a timepiece resonator, in particular a guide bearing for a timepiece pendulum tigeron. The invention also relates to a watch shock absorber or anti-shock device comprising such a bearing. The invention also relates to a clock mechanism comprising such a bearing or such a damper. The invention also relates to a watch movement comprising such a bearing or such a damper or such a mechanism. The invention also relates to a timepiece comprising such a bearing or such a damper or such a mechanism or such a movement.

The pivoting devices or conventional guide bearings balancer induce more or less significant friction on the pivots of the balance depending on the position of the oscillator. In general, the friction is higher in the vertical position of the watch, still called "hanging" position, than in the horizontal position of the watch or "flat" position, so that the oscillation amplitude of the balance is more weak in the vertical positions than in the horizontal positions of the watch. A difference in amplitude may in particular result in a difference in operation, hence the importance for the accuracy of the timepiece of minimizing the "flat-hung", that is to say the difference between walk between the "flat" position and the "hanging" position.

In conventional swing arm devices, the friction in the different positions varies because the configurations of the contact between the rocker pins and the guide stones change. In a horizontal watch position, the balance shaft is vertical and the end of the pivot of the shaft comes to rest on a stone called against pivot. In general, this stone is flat and the end of the pivot is rounded, so that the radius of the friction surface is low and the resulting friction is low. In a vertical watch position, the balance shaft is in a horizontal position and rubs on the edge of a hole, usually an olive hole and / or rounded edges formed in a stone. The friction is greater and the oscillation amplitude of the balance is therefore lower than horizontal watch position.

The document CH239786 discloses a pivoting device combining an olive stone and a counter-pivot abutment inclined relative to the shaft. This makes it possible to permanently induce a friction of the cylindrical portion of the shaft against the olive stone in the horizontal watch position, and therefore to increase the friction in this position.

The document US2654990 discloses a flat-end pivot and slightly rounded edges rubbing against a counter-pivot provided with a hemispherical depression. The goal is also to increase the friction in horizontal watch position by maximizing the radius of friction of the contact surface of the pivot in such a position.

In the same register, the patent application CH704770 proposes a pivot terminated by a bevel in order to increase the friction in horizontal watch position.

Due to pivoting games, including radial clearances, the above-mentioned embodiments induce different contact configurations between the pivot and the stone depending on the position of the watch. There are therefore differences in the path between the horizontal and vertical positions.

Monobloc dampers are also known in which the pivoting means of the balance pivot are manufactured in one piece with return means. For example, the document CH700496 relates to a simplified monobloc damper, the guide means of the rocker pivot bearing are implemented by elastic return means of the damper body. In conventional operation of the timepiece, these elastic return means press the pivot bearing against a stop formed by the body of the damper so that they have no effect on the pivot of balance. Moreover, no indication is given on the chronometric performance of such a device.

The document CH701995 relates to a bearing which has the particularity of being pressed against a rocker pivot under the effect of a spring arranged to apply a force directed axially relative to the shaft of the rocker pivot. The bearing and the spring are preassembled within a pivot structure ready to be mounted on the watch movement. The purpose is to remove the movements of the pivot, and thus the contact configuration variations between the pivot and the bearing, due to changes in position of the watch. Thus, in operation of the timepiece, the spring is prestressed so that it can act on the balance pivot, unlike a lyre of a conventional damper which acts only by reaction in case of a shock under the effect of the longitudinal displacement of the pendulum pivot. In preferred embodiments, the spring has a geometry close to that of a lyre. Alternatively, the spring may be in the form of a coil spring. It is also mentioned that the bearing and the spring can be monobloc. Such a solution is not optimal insofar as the preload of the spring is dependent on the axial location of the pivot structure, and therefore in particular many assembly tolerances. The document CH701995 discloses besides means for adjusting the prestressing of the spring by the axial displacement of the pivoting structure, for example by means of a bearing body whose outer periphery is threaded so that it can cooperate with a tapping formed on a pendulum bridge. Furthermore, it is also indicated that the force produced by the spring is dimensioned such that it allows appropriate behavior of the pivot device in case of impact. Pivoting and damping functions are therefore dependent on each other.

The patent application CH709905 discloses different embodiments of blade pivots. In an alternative embodiment, two blades supported by a beam are held in abutment in the groove bottom under the effect of elastically deformable arms. Such a structure requires a complex construction, defining two distinct virtual pivot trees. In alternative embodiments, blades biased by elastically deformable arms can define the same virtual pivot axis, but must be arranged in separate planes. Such embodiments are also not suitable for a conventional balance beam structure. In particular, the amplitude of oscillation on such pivots is very limited.

The object of the invention is to provide a guide bearing to overcome the drawbacks mentioned above and improve the watch bearings known from the prior art. In particular, the invention proposes a guide bearing of simple structure and making it possible to minimize the gap existing between the oscillating resistant torques of a resonator in the different horological positions.

A guide bearing according to the invention is defined by claim 1.

Different embodiments of the bearing are defined by claims 2 to 11.

A damper according to the invention is defined by claim 12.

A mechanism according to the invention is defined by claim 13.

An embodiment of the bearing is defined by claim 14.

A movement according to the invention is defined by claim 15.

A timepiece according to the invention is defined by claim 16.

• La figure 1 est une vue schématique d'un mode de réalisation d'une pièce d'horlogerie comprenant un premier mode de réalisation d'un palier de guidage.
• La figure 2 est une vue en perspective d'une première variante du premier mode de réalisation du palier de guidage.
• Les figures 3 et 4 sont des vues partielles de la première variante du premier mode de réalisation du palier de guidage, un arbre de balancier étant guidé par le palier.
• La figure 5 est une vue schématique d'une deuxième variante du premier mode de réalisation du palier de guidage.
• La figure 6 est une vue schématique d'une troisième variante du premier mode de réalisation du palier de guidage.
• La figure 7 est une vue en perspective d'un deuxième mode de réalisation du palier de guidage.
• Les figures 8 et 9 sont des vues schématiques du deuxième mode de réalisation du palier de guidage, un arbre de balancier étant guidé par le palier.
• La figure 10 est une vue schématique du deuxième mode de réalisation du palier de guidage, sans arbre de balancier guidé par le palier.
• Les figures 11 à 13 sont des vues schématiques illustrant des structures globales de palier applicables en particulier au premier mode de réalisation du palier de guidage ou au deuxième mode de réalisation du palier de guidage.
• La figure 14 est une vue de face d'une première variante d'un troisième mode de réalisation du palier de guidage.
• La figure 15 est une vue de face d'une deuxième variante du troisième mode de réalisation du palier de guidage.
• La figure 16 est une vue de face d'une troisième variante du troisième mode de réalisation du palier de guidage.
• La figure 17 est un graphique illustrant, pour les différentes positions horlogères, les évolutions du facteur de qualité FQ d'un résonateur dont le balancier est guidé par un palier selon l'art antérieur, en fonction de l'amplitude A des oscillations du résonateur.
• La figure 18 est un graphique illustrant, pour les différentes positions horlogères, les évolutions du facteur de qualité FQ d'un résonateur dont le balancier est guidé par un palier selon le deuxième mode de réalisation, en fonction de l'amplitude A des oscillations du résonateur.

The appended figures represent, by way of example, embodiments of a timepiece according to the invention.

• The figure 1 is a schematic view of an embodiment of a timepiece comprising a first embodiment of a guide bearing.
• The figure 2 is a perspective view of a first variant of the first embodiment of the guide bearing.
• The Figures 3 and 4 are partial views of the first variant of the first embodiment of the guide bearing, a rocker shaft being guided by the bearing.
• The figure 5 is a schematic view of a second variant of the first embodiment of the guide bearing.
• The figure 6 is a schematic view of a third variant of the first embodiment of the guide bearing.
• The figure 7 is a perspective view of a second embodiment of the guide bearing.
• The figures 8 and 9 are schematic views of the second embodiment of the guide bearing, a balance shaft being guided by the bearing.
• The figure 10 is a schematic view of the second embodiment of the guide bearing, without balance shaft guided by the bearing.
• The Figures 11 to 13 are schematic views illustrating overall bearing structures applicable in particular to the first embodiment of the guide bearing or the second embodiment of the guide bearing.
• The figure 14 is a front view of a first variant of a third embodiment of the guide bearing.
• The figure 15 is a front view of a second variant of the third embodiment of the guide bearing.
• The figure 16 is a front view of a third variant of the third embodiment of the guide bearing.
• The figure 17 is a graph illustrating, for the different watch positions, the changes in the quality factor FQ of a resonator whose balance is guided by a bearing according to the prior art, as a function of the amplitude A oscillations of the resonator.
• The figure 18 is a graph illustrating, for the different watch positions, the changes in the quality factor FQ of a resonator whose balance is guided by a bearing according to the second embodiment, as a function of the amplitude A oscillations of the resonator.

An embodiment of a timepiece 130 is described below with reference to the figure 1 . The timepiece is for example a watch, in particular a wristwatch. The timepiece comprises a watch movement 120, including a mechanical watch movement.

The movement comprises a clock mechanism 110, in particular an oscillator connected to an energy source, such as a cylinder, by a finishing gear. The oscillator comprises a resonator, in particular a resonator of the spring-balance type. The resonator comprises a shaft 2 (shown, for example, schematically on the Figures 3 and 4 ), for example a balance shaft.

The mechanism comprises at least one guide bearing, in particular at least one bearing 1a; 1b; 1a '; 1b '; 1c 'of rotation guide of the resonator, at a shaft portion. This at least one bearing is advantageously part of a damper 100 forming part of the mechanism. Preferably, to guide the resonator in rotation, the mechanism comprises two dampers 100 each comprising a guide bearing of the resonator. In a preferred manner, the resonator is pivoted on both sides of the shaft 2 by two bearings. Advantageously, the mounting of the resonator shaft in the guide bearing causes the elastic deformation of at least a portion of the bearing. It follows that after mounting the shaft in the guide bearing, the latter is prestressed.

Advantageously, the damper or dampers 100 comprise a counter-pivot stone biased into a stable position by the action of a spring and capable of being displaced axially relative to the axis of the resonator against the action of the spring in case of shock or acceleration moving the resonator against this counter-pivot stone. The spring known as the lyre is intended to take up the efforts of the resonator shaft via the counter-pivot stone, the function of which is to delimit the frost, in particular the axial frustum, of the resonator shaft. In case of shock, the forces suffered by the shaft are taken up by the lyre via the counter-pivot stone. In conventional operation of the timepiece, the lyre plates the counter-pivot stone and the pivot stone against a stop defined by the body of the damper so that the lyre has no effect axial on the resonator shaft. Thus, the resonator shaft is mounted axially within the damper.

The damper (s) 100 may comprise a pivot stone. In this case, the resonator may, in case of shock or acceleration moving the resonator radially relative to the axis of the resonator against the action of the guide bearing, abut against this pivot stone, after the bearing has been deformed to a certain degree.

Alternatively, the damper (s) 100 may not include pivot stone. In this case, the guide bearing 1a; 1b; 1a '; 1b '; 1c 'may come instead of the pivot stone of a shock absorber known from the prior art.

In general, the bearing 1a; 1b; 1a '; 1b '; 1c 'guiding guide, along an axis 21, the shaft 2, in particular the shaft of the resonator. The bearing comprises at least one support element 13a; 13b; 131a; 132a; 13a '; 13b '; 13c 'arranged so as to exert, on the radial axis or substantially radially to the axis, an action on the shaft, in particular a force on the shaft, permanently. The action may however be inclined relative to the radial direction to the axis 21 because of the coefficient of friction at the shaft-bearing element interface.

Preferably, the action or actions are exerted perpendicular to the axis 21 of the shaft. The rotational guidance function can therefore be dissociated from the axial force recovery function. For example, the direction of the action or actions forms an angle less than 20 ° or less than 10 ° or less than 5 ° with a plane perpendicular to the axis 21.

By "exercising permanently", it is intended to carry out the action or actions constantly in time, when the resonator is put in place in the rest of the movement, whatever the position of the movement in space, in particular whatever the position of the resonator in space. The contact between a support element and the shaft can nevertheless be broken momentarily when the movement is subjected to an acceleration greater than a predefined threshold, for example a threshold of the order of 1 g which corresponds to the intensity of the field of view. terrestrial gravitation, especially a threshold between 0.1g and 1g. Such a threshold gap advantageously makes it possible to better dimension the bearing with respect to energy considerations, especially with regard to the friction induced by the bearing against the shaft. The acceleration threshold may nevertheless be set at any other value, in particular in preference to any other value greater than or equal to 1 g, in particular of the order of 2 g.

Advantageously, the intensity of the torque resisting the movement of the resonator due to the action or actions exerted by the at least one bearing element on the shaft is constant or substantially constant, particular constant in time, when the resonator is set up in the rest of the movement and when the resonator is in motion, regardless of the position of the movement in space, especially regardless of the position of the resonator in space . Advantageously, the intensity of the action or actions exerted by the at least one support element on the shaft is constant or substantially constant, in particular constant over time, once the resonator has been put in place in the rest movement, whatever the position of the movement in space, especially whatever the position of the resonator in space.

The shaft portion guided by the bearing may be a pivot or a tigeron. The pivot may in particular have a cylindrical or frustoconical section.

Preferably, the bearing comprises at least one element 12a; 12b; 12a '; 12b '; 12c 'cooperating with the at least one support element. Thus, it is the at least one element 12a; 12b; 12a '; 12b '; 12c 'reminder that recalls the at least one support element 13a; 13b; 131a; 132a; 13a '; 13b '; 13c 'in contact on the shaft 2. This at least one return element is advantageously elastically deformable. Thus, the return force of the at least one bearing element on the shaft is produced by the elastic deformation of the at least one return element. The at least one return element is defined or dimensioned so as to ensure the permanence of the contact as long as the acceleration experienced by the timepiece remains below the acceleration threshold described above.

• au moins un élément d'appui 13a sur l'arbre, et
• un élément de rappel 12a de l'au moins un élément d'appui sur l'arbre.

In a first embodiment described below with reference to Figures 2 to 6 the bearing comprises at least one curved blade 14a, in particular three curved blades, or even more than three curved blades, in particular four or five curved blades, each constituting:

• at least one support member 13a on the shaft, and
• a return element 12a of the at least one support element on the shaft.

Preferably, the blades are curved in the form of a spiral. The spiral may in particular be such that it is defined by a polar equation in which the radius is proportional to the angle or in which the radius is proportional to the angle raised to a power. Alternatively, the blades can have any shape as long as they have adequate stiffness. They can have a zigzag shape, straight, curved. The blades can be bent more than 180 °, in particular about 270 °, between their two ends. The curved shapes of the blades optimize their size for a given dimensioning so as to obtain mechanical stress characteristics in the blades and rigidity characteristics of the blades that are adequate for the application. The shapes of the blades can be flat (especially in a plane perpendicular to the axis of the bearing). The shapes of the blades can also be non-planar. Thus, it is possible to increase the active lengths of the blades.

In a first variant of the first embodiment described below with reference to the Figures 2 to 4 , the bearing mainly comprises a frame 11a, in particular an annular frame, and blades 14a extending towards the inside of the frame, in particular three blades. The blades extend for example from an inner surface of the annular frame. Each blade has a convex face and a concave face. A first end of each blade is attached or attached to the frame. A second end of each blade is free. In the vicinity of these second free ends, the concave faces can form the support elements on the shaft. Each support element is for example a portion of a concave face in the vicinity of a free end of a blade. In the variant shown, the support elements are formed at the level of the portions of faces by concave surfaces. The radii of curvature of these concave surfaces are greater than the radius of the shaft 2 that the bearing is intended to receive. For example, the radii of curvature of these concave surfaces at the level of the support elements are greater than 5 times the radius of the shaft 2 that the bearing is intended to receive.

• la portion de face concave constituant l'élément d'appui,
• du châssis.

Each support element is mechanically connected to the frame by means of a return element. This return element is constituted by the blade portion separating:

• the concave face portion constituting the support element,
• of the chassis.

The diameter of the internal face of the frame can be 30 times, even 40 times, the diameter of the shaft 2.

In a second variant of the first embodiment described below with reference to the figure 5 , the bearing differs from the bearing described in the first variant of the first embodiment in that the bearing elements 131a extend perpendicularly or substantially perpendicular to the free ends of the blades in a plane perpendicular to the axis 21. Bearing elements 131a are, in this variant, cylinder portions disposed perpendicularly or substantially perpendicularly to the free ends of the blades. Such a conformation particularly promotes the positioning and stability of the pivot relative to the bearing. Thus, it can be guaranteed that the axis 21 of the shaft 2 remains in a defined neighborhood of its centered position in the bearing even under the effect of significant efforts on the resonator.

In a third variant of the first embodiment described hereinafter with reference to FIG. figure 6 , the bearing differs from the bearing described in the second variant of the first embodiment in that the bearing elements 132a comprise abutments or hooks 133a arranged so as to limit the deformations of the return elements 12a. Thus, it can be guaranteed that the axis 21 of the shaft 2 remains in a defined neighborhood of its centered position in the bearing even under the effect of significant efforts on the resonator. This avoids any risk of breakage of the blades during assembly of the bearing, in particular during the introduction of the shaft 2 in the bearing, or during operation of the movement when the resonator is in motion. The stops are for example formed by arms extending substantially perpendicularly to the surfaces of the bearing elements which bear against the shaft. These stops are intended to cooperate with another bearing element adjacent to the bearing. On the figure 6 the different elements are represented in a configuration where the stops are not active, that is to say a configuration where they do not cooperate by contact with an adjacent element.

In a second embodiment described below with reference to Figures 7 to 10 , the bearing differs from the bearing described in the first embodiment in that the blades 14b are straight or rectilinear (and not curved). In addition, in this embodiment, the surfaces of the bearing elements in contact with the shaft 2 are planar. The flexible blades are therefore in the form of straight beams. Their sections can be constant.

In this embodiment, the bearing comprises stops limiting the deformation of the return elements. Indeed, the blades remain close to surfaces 16 of the frame constituting stops. When a certain degree of deformation of a return element is reached, the blade comes into contact against this stop and its deformation is thus limited. This avoids any risk of breakage of the blades during assembly of the bearing, in particular during the introduction of the shaft 2 in the bearing, or during operation of the timepiece when the resonator is in motion , especially in case of shock.

Whatever the variant of the first two embodiments, the return elements are constituted by a portion of a flexible blade. Preferably, the various flexible blades are made of material of a single piece thus forming a one-piece bearing including the frame.

Whatever the variant of the first two embodiments, the resonator shaft can be pivoted between the flexible blades. Whatever the position of the resonator, the blades, in particular the support elements, are pressed against the shaft under the effect of their respective prestressing. Indeed, the blades, in particular the return elements, are deformed elastically when the shaft is introduced into the bearing. This elastic deformation causes a return force tending to bring the blades back to their original position during the introduction of the shaft.

As shown on the figure 3 in the horizontal position of the watch (vertical position of the axis 21), each of the blades exerts the same force, ideally minimized as far as possible, on the shaft. This force is ideally suited to induce friction substantially equal to the friction acting in a vertical position. The contact between the blades and the shaft can be broken momentarily when the movement is subjected to an acceleration greater than a predefined threshold. A threshold which can be between 0.5 g and 1 g advantageously allows minimize as much as possible the friction of the blades against the shaft.

In the horizontal position of the watch, the weight of the shaft is theoretically not taken up by the bearing. The weight is, for example, taken up by a counter-pivot stone. As shown on the figure 4 in the vertical position of the watch (horizontal position of the axis 21), the weight of the resonator is taken up by the blade or blades of the bearing. This causes a slight displacement (perpendicular to the axis 21). This displacement is advantageously similar or lower than those known within the conventional bearings. As a result of this movement, the blade or blades located above the shaft exert a lower force on the shaft than those below. As long as all the blades remain in contact with the shaft, the sum of the intensities of the forces of the blades on the shaft remains essentially the same regardless of the position of the resonator. When the resonator is mobile in the movement, the intensity of the friction torque resulting from the forces of the blades on the shaft then also remains essentially the same regardless of the position of the resonator. This has the effect of balancing the quality factors of the resonator between the different watch positions.

On the figure 10 a bearing is partially shown in the absence of the shaft mounted in the bearing. In this configuration, the three blades define an inscribed circle of radius r0.

When mounting the shaft in the bearing, the flexible blades are elastically deformed, or preloaded, over a distance rp-r0, rp being the radius of the shaft at the support of the blades on the shaft.

• F0 =k.(rp-r0) où k est la raideur de chacune des lames flexibles.

The prestressing force F0 of each of the flexible blades is thus given by:

• F0 = k. (Rp-r0) where k is the stiffness of each of the flexible blades.

• cette force de précontrainte F0 (tant que celle-ci est strictement positive au niveau de chacune des lames),
• le coefficient de frottement n entre l'arbre et chacune des lames flexibles, et
• le rayon rp de l'arbre.

Studies, based on static force balances, show that the static friction torque C induced by the flexible blades against the resonator shaft is constant or substantially constant regardless of the position of the resonator in space , and that this essentially depends on:

• this prestressing force F0 (as long as it is strictly positive at each of the blades),
• the coefficient of friction n between the shaft and each of the flexible blades, and
• the radius rp of the tree.

Ainsi : $$\mathrm{C}=\mathrm{3.}\mathrm{\eta }\mathrm{.}\mathrm{F}\mathrm{0.}\mathrm{rp\; ou\; C}=\mathrm{3.}\mathrm{\eta }\mathrm{.}\mathrm{k}\left(\mathrm{rp}-\mathrm{r}\mathrm{0}\right)\mathrm{.}\mathrm{rp}$$

Thus, the static friction torque C, regardless of the position of the resonator, is equal to or substantially equal to the static friction torque CH induced by the flexible blades against the resonator shaft when the watch is in the horizontal position. (shaft 2 and axis 21 oriented vertically). In this configuration represented on the figure 9 , and in the case where the weight P is oriented exclusively along the axis of rotation of the shaft) of the resonator, the torque CH can be expressed as follows: $$\mathrm{CH}=\mathrm{3.}\mathrm{\eta }\mathrm{.}\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0.}\mathrm{rp\; or\; CH}=\mathrm{3.}\mathrm{\eta }\mathrm{.}\mathrm{k}\left(\mathrm{rp}-\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="imgf0007.png"\; state="\{\{state\}\}">r</figure-callout>}\mathrm{0}\right)\mathrm{.}\mathrm{rp}$$

So : $$\mathrm{VS}=\mathrm{3.}\mathrm{\eta }\mathrm{.}\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0.}\mathrm{rp\; or\; C}=\mathrm{3.}\mathrm{\eta }\mathrm{.}\mathrm{k}\left(\mathrm{rp}-\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="imgf0007.png"\; state="\{\{state\}\}">r</figure-callout>}\mathrm{0}\right)\mathrm{.}\mathrm{rp}$$

This value C being constant or substantially constant regardless of the position of the watch, it has the effect of balancing the quality factors of the oscillator between the different positions.

For example, the figure 18 illustrates a graph representing different FQ quality factors according to oscillator amplitude of an oscillator and the spatial position of a watch having an oscillator pivoted by two bearings such as that illustrated in FIG. figure 7 . It is observed that these FQ quality factors are homogenized regardless of the position of the resonator, and significantly in relation to the quality factors FQ of the same conventionally rotated resonator shown in FIG. figure 17 .

• F0>2.P/3 avec P l'effort exercé par le résonateur au niveau du palier

The prestressing force F0 can be minimized as much as possible depending on the resonator chosen so as to optimize the energy required for the maintenance of its oscillations. The minimum intensity of the force Fm is defined by the limiting case in which the force Fi (F2 on the figure 8 ) produced by one of the flexible blades is canceled under the effect of the weight of the resonator (1g maximum acceleration). Calculations show that this case can not be reached if, with constant friction n:

• F0> 2.P / 3 with P the stress exerted by the resonator at the level

By respecting this criterion, F0 can be minimized to the best possible extent so as to produce the lowest possible static friction torque while balancing the frictional moments in all the horizontal and vertical positions.

More particularly, the stiffness k of each of the flexible blades must satisfy the criterion: $$\mathrm{k}>\mathrm{2.}\mathrm{P}/\left(\mathrm{3.}\left(\mathrm{rp}-\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="imgf0007.png"\; state="\{\{state\}\}">r</figure-callout>}\mathrm{0}\right)\right)$$

Whatever the variant of the first two embodiments, the sections of these blades may be constant or not. Each of these blades may also consist of several blades, integral or not, so as to optimize and differentiate their stiffness according to the different displacements or positions of the resonator. For example, such an embodiment would make it possible to minimize the radial bearing force at against the shaft in order to minimize the frictional forces against the shaft while ensuring the centering of the shaft in the bearing.

• la ou les lames s'étendent parallèlement ou sensiblement parallèlement aux éléments d'appui au voisinage des éléments d'appui et/ou orthogonalement ou sensiblement orthogonalement à l'axe au voisinage des éléments d'appui, ou
• la ou les lames s'étendent perpendiculairement ou sensiblement perpendiculairement aux éléments d'appui au voisinage des éléments d'appui et/ou orthogonalement ou sensiblement orthogonalement à l'axe au voisinage des éléments d'appui.

Whatever the variant of the first two embodiments:

• the blade or blades extend parallel or substantially parallel to the support elements in the vicinity of the support elements and / or orthogonally or substantially orthogonal to the axis in the vicinity of the support elements, or
• the blade or blades extend perpendicularly or substantially perpendicular to the support elements in the vicinity of the support elements and / or orthogonally or substantially orthogonal to the axis in the vicinity of the support elements.

Whatever the first and second embodiments, the blades, and more generally the bearings, may for example be made of nickel, a nickel-phosphorus alloy, or silicon and / or coated silicon (silicon oxide , silicon nitride, ...). Such components can be manufactured in a preferred manner by electroforming or etching. Alternatively, such components could be machined by electroerosion.

• au moins un élément d'appui sur l'arbre, et
• un élément de rappel d'au moins un élément d'appui sur l'arbre.

In a third embodiment described below with reference to Figures 14 to 16 , the bearing comprises at least one protuberance 14a ', 14b' radial or substantially radial, each protuberance comprising:

• at least one support element on the shaft, and
• a return element of at least one support element on the shaft.

Thus, preferably, the bearing comprises a ring having a geometry including several protuberances or lobes directed towards the axis of the ring, in particular directed towards the axis of the ring and extending from a surface of the ring directed towards the inside of the ring. Preferably, the ring comprises at least two protuberances. It may include two or three or four or five or six protuberances.

Preferably, the bearing comprises a ring of elastomeric material. The bearing can be made of natural rubber or synthetic rubber such as neoprene, polybutadiene, polyurethane or silicone.

Alternatively, the ring may have a constant section. In this case it may have a bearing element comprising a continuous surface bearing on the shaft over its entire circumference or on the majority of its circumference, for example more than 240 ° or more than 270 ° or more than 300 ° . In this variant, the bearing therefore comprises a single bearing element on the shaft. This support element is constituted by the surface in contact with the shaft. An annular portion of the ring located between the surface in contact with the shaft and the larger diameter surface of the ring constitutes a return element, in this case a single return element.

In a first variant of the third embodiment described below with reference to the figure 14 , the bearing 1a 'comprises three protuberances 14a'. Each protuberance comprises a support element 13a 'on the shaft and a return element 12a' of the support element in contact with the shaft. The support elements are constituted by surfaces of the protuberances in contact with the shaft. The return elements are constituted by the material of the protuberances connecting the support elements to the remainder of the ring 11a 'constituting a frame and having a constant section. The protuberances are lobes or bosses filled with matter.

In a second variant of the third embodiment described below with reference to the figure 15 , the bearing differs from the first variant of the third embodiment of the bearing in that the protuberances are lobes or bosses in which cutouts 91 have been made. Thus, the bearing may comprise at least one radial or substantially radial protuberance, each protuberance comprising at least one bearing element on the shaft and a return element of at least one bearing element on the shaft, the or the return elements including cutouts. By "cutting", it is necessary here to hear any recess that may in particular have been made by a different technique of a cut, in particular by molding. These cutouts 91 make it possible to adjust the stiffness of each of the protuberances.

In a third variant of the third embodiment described below with reference to the figure 16 , the bearing differs from the first variant of the third mode or the second variant of the third embodiment in that the ring is mechanically connected to, in particular fixed to, in particular overmolded on a ring 11c 'constituting the frame.

Whatever the embodiment and whatever the variant, the at least one return element and the at least one support element are preferably monobloc.

In the variants and embodiments described, the bearing has three return elements and three support elements. However, whatever the embodiment and whatever the variant, the bearing may have a different number of three return elements and three support elements. In particular, whatever the embodiment and whatever either the variant, the bearing may have one or two or three or four or five or six return elements and one or two or three or four or five or six support elements. Preferably, the bearing has as many return elements as support elements.

Whatever the embodiment and whatever the variant, the bearing surface bearing against the shaft 2 of each support element may be flat or concave or convex. In particular, all the bearing surfaces may be flat or concave or convex.

Whatever the embodiment and whatever the variant, the frame, including the annular frame, can be manufactured in one piece or made of several independent parts, including as many independent parts as return elements. In the case where the blades are made independently of each other, they are each fixed to a base 111a. The bases are advantageously provided with positioning elements and possibly adjustment elements, in particular centering elements, such as holes. These positioning elements make it possible to define the axis of the bearing. Such an embodiment with a base is represented on the figure 12 . The positioning elements cooperate for example with pins.

Whatever the embodiment and whatever the variant, the bearing can be provided with assembly means of the bearing. For example, the frame may comprise a split ring so as to allow its elastic deformation and thus allow adequate positioning of the blades during assembly as shown in FIG. figure 13 . The frame may also comprise a continuous ring as shown on the figure 11 .

Whatever the embodiment and whatever the variant, the bearing may comprise stops for limiting the deformation of the return elements.

Whatever the embodiment and whatever the variant, the support elements and / or the return elements are preferably uniformly distributed angularly around the axis 21.

The solutions described are intended to remedy the problem of difference in position between positions by providing a shaped bearing so as to generate a substantially constant force on a shaft of a resonator, regardless of the position of the resonator. To do this, the bearing has the particularity of being provided with at least one return means provided for applying a substantially radial force against a resonator shaft, and whatever the position of the resonator.

The bearing is provided with at least one return means which is provided to apply a substantially radial force against the shaft so as to induce a substantially constant force between the shaft and the bearing, and whatever the position of the watch.

In this way, the difference between the positions is reduced to a minimum. Thus, the quality factor of the resonator can be constant or substantially constant regardless of the position of the resonator, and the chronometric performance of the movement optimized.

The biasing means preferably function to support and position, at least in the transverse plane of the bearing, the shaft of the resonator.

Whatever the embodiment, the bearing can be integrated within a damper, especially within a damper whose structure is conventional.

In a damper according to the invention, it is noted that an axial damping function can be dissociated from the radial damping function. Indeed, the axial damping is mainly provided by a conventional counter-pivot stone and lyre. A radial damping function can be provided by the bearings.

Claims (16)

Bearing (1a; 1b; 1a '; 1b'; 1c ') for guiding along an axis (21) of a timepiece shaft (2) (130), in particular a guide bearing for a portion (2) of a shaft of a timepiece resonator, comprising at least one support element (13a; 13b; 131a; 132a; 13a '; 13b'; 13c ') arranged to exert, radially to the axis or substantially radially to the axis, an action on the shaft, permanently. Bearing according to the preceding claim, characterized in that it comprises at least one element (12a; 12b; 12a ';12b'; 12c ') of return cooperating with the at least one support element. Bearing according to the preceding claim, characterized in that the at least one element (12a; 12b; 12a; 12b ';12b'; 12c ') of return and the at least one support element are monobloc. Bearing according to one of the preceding claims, characterized in that it comprises at least two elements (13a; 13b; 131a; 132a; 13a ';13b'; 13c ') bearing on the shaft about the axis (21). Bearing according to one of the preceding claims, characterized in that it comprises at least two return elements, in particular three return elements, and at least as many support elements. Bearing according to one of the preceding claims, characterized in that each of the at least one support element comprises at least one bearing surface (9) planar or concave or convex, including all bearing surfaces being flat or concave or convex. Bearing according to one of the preceding claims, characterized in that it comprises at least one blade (14a; 14b), in particular three blades, or even more than three blades, each constituting: at least one element (13a, 13b, 131a, 132a) for bearing on the shaft, and an element (12a; 12b) for returning the at least one support element to the shaft. Bearing according to the preceding claim, characterized in that : the blade or blades extend parallel or substantially parallel to the support elements in the vicinity of the support elements and / or orthogonally or substantially orthogonal to the axis in the vicinity of the support elements, or in that - The blade or blades extend at least substantially perpendicular to the support elements in the vicinity of the support elements and / or orthogonal or substantially orthogonal to the axis in the vicinity of the support elements. Bearing according to claim 7 or 8, characterized in that the blade or blades extend at least substantially rectilinearly or in that the blade or blades extend along curves, in particular at least substantially in spirals. Bearing according to one of claims 1 to 6, characterized in that it comprises at least one protuberance (14a ';14b') radial or substantially radial, each protuberance comprising: at least one element (13a ';13b'; 13c ') for bearing on the shaft, and an element (12a ';12b'; 12c ') for restoring at least one support element on the shaft. Bearing according to one of the preceding claims, characterized in that it comprises an annular frame (11a; 111a; 112a; 11b; 112b; 11a ';11b'; 11c '), the support elements being mechanically connected to the frame by means of the return elements and / or in that the annular frame is manufactured in one piece or made of several independent parts, in particular in as many independent parts as return elements, and / or in that it comprises abutments (133a) for limiting the deformation of the return elements and / or in that the support elements and / or restoring elements are regularly distributed angularly about the axis (21). Damper (100), comprising a bearing (1) according to one of the preceding claims and a counter-pivot stone. Watchmaker mechanism (110), in particular a pendulum oscillator, comprising at least one bearing according to one of claims 1 to 11 or a damper according to the preceding claim and a shaft (2) mounted in the at least one bearing. Mechanism according to the preceding claim, characterized in that the mechanism comprises a resonator comprising a balance and / or in that the mechanism comprises a resonator of which a shaft portion or a tigeron is guided by the bearing and / or in that the at least one biasing element is prestressed. Clock movement (120) comprising at least one bearing according to one of claims 1 to 11 or a damper according to claim 12 or a mechanism according to claim 13 or 14. Timepiece (130), especially a wristwatch, comprising a movement according to the preceding claim or a mechanism according to claim 13 or 14 or a damper (100) according to claim 12 or at least one bearing according to one of claims 1 at 11.

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