Clock mechanism

Abstract

The present invention provides a guide bearing capable of improving conventionally known timepiece bearings, and proposes a guide bearing with a simple structure capable of minimizing the difference between the torques resisting the oscillation of the resonator at various timepiece device positions. [Solution] A bearing 1a for guiding a clock shaft around a rotation axis, in particular a guiding bearing for a portion of a clock resonator shaft, comprising at least one pressing element 13a arranged radially or substantially radially relative to the rotation axis so as to constantly act on the shaft.

Description

[Technical field]

[0001] The present invention relates to a bearing for guiding the rotation of a clock shaft, in particular a guiding bearing for a clock shaft part or a resonator pivot, in particular a guiding bearing for a clock balance pivot shank. The present invention also relates to a watch shock absorber or shock absorber device comprising such a bearing. The present invention also relates to a clock mechanism comprising such a bearing or such a shock absorber. The present invention also relates to a clock movement comprising such a bearing or such a shock absorber or such a mechanism. The present invention also relates to a clock comprising such a bearing or such a shock absorber or such a mechanism or such a movement. [Background technology]

[0002] Conventional balance guide bearings or pivot devices introduce friction at the balance pivot, the magnitude of which varies with the position of the oscillator. Generally, friction is higher when the watch is in a vertical position, also called a "hanging" position, compared to when it is in a horizontal or "flat" position. This means that the amplitude of the oscillations of the balance is lower when the watch is in a vertical position than when it is in a horizontal position. The difference in amplitude can be manifested, among other things, as a difference in advance, hence the importance for the accuracy of the watch of minimizing the "flat-hanging" difference, i.e. the difference in advance between the "flat" and "hanging" positions.

[0003] In a conventional balance pivot device, the friction in different positions varies due to the configuration of the contact between the balance pivot and the guide jewel. When the watch is in a horizontal position, the balance is vertical and the tip of the axle pivot presses against a jewel known as a bridge jewel. Typically, the jewel is flat and the tip of the pivot is rounded. This means that the friction surface has a small radius and the resulting friction is low. When the watch is in a vertical position, the balance is in a horizontal position and rubs against the edge of a hole, typically an olive hole and / or a hole with rounded edges, formed in the jewel. The friction is higher and therefore the amplitude of the oscillation of the balance is lower than when the watch is in a horizontal position.

[0004] Patent document 1 discloses a pivot device that combines an olive jewel with a tilted jewel that is inclined relative to the axis, which means that friction between the barrel of the axis and the olive jewel occurs all the time when the watch is in a horizontal position, thus increasing friction in that position.

[0005] US Pat. No. 5,399,433 discloses a pivot with a flat tip and slightly rounded edges that rubs against a jewel with a hemispherical recess, the aim here again being to increase friction at this position by maximizing the rubbing radius of the pivot contact surfaces when the watch is in a horizontal position.

[0006] In a similar vein, patent US 5,399,633 proposes a pivot terminating in a chamfer with the purpose of increasing friction when the watch is in a horizontal position.

[0007] Due to the pivoting clearances, especially the radial clearances, the above embodiment causes different contact configurations between the pivot and the jewel depending on the position of the watch, so that the advance difference between the horizontal and vertical positions remains the same.

[0008] Also known are integral buffers, in which the pivoting means of the balance pivot are manufactured integrally with the return means. For example, US Pat. No. 5,399,433 relates to a simplified integral buffer, in which the balance pivot bushing guiding means are embodied by means for elastically returning the buffer body. In conventional timekeeping, these elastic return means press the pivot bushing firmly against a ramp formed in the buffer body, and thus have no effect on the balance pivot. Furthermore, no information is given about the chronometric performance of the device.

[0009] Patent document 5 relates to a bearing that exhibits the feature of being pressed firmly against the balance pivot under the effect of a spring designed to exert a radially directed force on the balance pivot axis. The bearing and the spring are preassembled in a pivot structure ready for mounting in the watch movement. The aim is to eliminate the movement of the pivot and therefore the change in the structure of the contact between the pivot and the bearing as a result of the change in the position of the small watch. For this reason, during the running of the watch, the spring is preloaded so that it can act on the balance pivot, unlike the anti-shock springs of conventional buffers that act only by rebound in case of shocks under the effect of a longitudinal movement of the balance pivot. In a preferred embodiment, the spring has a shape similar to that of an anti-shock spring. Alternatively, the spring may take the shape of a helical spring. It is also mentioned that the bearing and the spring can be manufactured in one piece. This solution is not optimal, since the preload of the spring depends on the axial arrangement of the pivot structure and therefore, inter alia, on a number of assembly tolerances. The patent also discloses a method of adjusting the spring preload by moving the pivot structure axially, for example by the action of a threaded bearing body that cooperates with a tapping provided on the outer periphery of the balance. Furthermore, the patent further discloses that the force generated by the spring is evaluated to allow the pivot device to move appropriately when subjected to impact. Thus, the pivoting and impact resistance functions are interdependent.

[0010] US Pat. No. 5,399,433 discloses various embodiments of a bladed pivot. In one variant of the embodiment, two blades supported by the balance are kept pressed against the bottom of the groove under the influence of an elastically deformable arm. The structure involves a complex construction that defines two separate virtual pivot axes. In an alternative embodiment, the blades returned by the elastically deformable arm can define a single virtual pivot axis, but they must be located in separate planes. Such an embodiment is not suitable for conventional balance structures. In particular, the amplitude of oscillation of the pivot is very limited. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Swiss Patent Application Publication No. 239786 [Patent Document 2] U.S. Patent No. 2,654,990 [Patent Document 3] Swiss Patent Application Publication No. 704770 [Patent Document 4] Swiss Patent Application Publication No. 700496 [Patent Document 5] Swiss Patent Application Publication No. 701995 [Patent Document 6] Swiss Patent Application Publication No. 709905 Summary of the Invention [Problem to be solved by the invention]

[0012] The object of the present invention is to provide a guide bearing capable of overcoming the above-mentioned drawbacks and improving the previously known timepiece bearings. In particular, the present invention proposes a guide bearing of simple construction, capable of minimizing the differences existing between the torques resisting the oscillation of the resonator at the various timepiece positions. [Means for solving the problem]

[0013] The guide bearing according to the invention is defined in claim 1.

[0014] Various embodiments of the bearing are defined in claims 2 to 11.

[0015] The shock absorber according to the invention is defined in claim 12.

[0016] The mechanism according to the invention is defined in claim 13.

[0017] An embodiment of the bearing is defined in claim 14.

[0018] A movement according to the invention is defined in claim 15.

[0019] A watch according to the invention is defined in claim 16.

[0020] The accompanying drawings illustrate, by way of example, embodiments of a watch according to the invention. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of an embodiment of a timepiece including a first embodiment of a guide bearing. [Diagram 2] FIG. 2 is a perspective view of a first alternative of the first embodiment of the guide bearing. [Diagram 3] FIG. 3 shows a partial view of a first alternative of the first embodiment of the guide bearing, in which the balance shaft is guided by the bearing. [Figure 4] FIG. 4 shows a partial view of a first alternative of the first embodiment of the guide bearing, in which the balance shaft is guided by the bearing. [Diagram 5] FIG. 5 is a schematic view of a second alternative to the first embodiment of the guide bearing. [Figure 6] FIG. 6 is a schematic view of a third alternative to the first embodiment of the guide bearing. [Figure 7] FIG. 7 is a perspective view of a second embodiment of a guide bearing. [Figure 8] FIG. 8 is a schematic diagram of a second embodiment of a guide bearing, in which the balance shaft is guided by a bearing. [Figure 9] FIG. 9 is a schematic diagram of a second embodiment of a guide bearing, in which the balance shaft is guided by a bearing. [Figure 10] FIG. 10 is a schematic diagram of a second embodiment of a guide bearing without a balance stem guided by a bearing. [Figure 11] FIG. 11 is a schematic diagram illustrating the overall bearing construction, particularly applicable to the first guide bearing embodiment or the second guide bearing embodiment. [Figure 12] FIG. 12 is a schematic diagram illustrating the overall bearing construction, particularly applicable to the first guide bearing embodiment or the second guide bearing embodiment. [Figure 13] FIG. 13 is a schematic diagram illustrating the overall bearing construction, particularly applicable to the first guide bearing embodiment or the second guide bearing embodiment. [Figure 14] FIG. 14 is a top view of a first alternative of the third embodiment of the guide bearing. [Figure 15] FIG. 15 is a top view of a second alternative of the third embodiment of the guide bearing. [Figure 16] FIG. 16 is a top view of a third alternative of the third embodiment of the guide bearing. [Figure 17] FIG. 17 is a graph showing the variation of the quality factor FQ of a balance resonator guided in a bearing of the prior art, in various horological positions, as a coefficient of the amplitude A of the resonance of the resonator. [Figure 18] FIG. 18 is a graph showing the variation of the quality factor FQ of the resonator of a balance guided in a bearing according to the second embodiment in various horological device positions as a coefficient of the amplitude A of the resonance of the resonator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An embodiment of a watch 130 is described below with reference to Fig. 1. The watch is for example a watch, in particular a wristwatch. The watch includes a watch movement 120, in particular a mechanical watch movement.

[0023] The movement includes a clockwork 110, in particular an oscillator connected by a gear train to a power source such as a mainspring barrel. The oscillator includes a resonator, in particular a balance-wheel and hairspring type resonator. The resonator includes an axis 2, for example a balance shaft (schematically illustrated, for example, in Figures 3 and 4).

[0024] The mechanism comprises at least one guide bearing, in particular at least one bearing 1a; 1b; 1a'; 1b'; 1c', on the shaft section for guiding the rotation of the resonator. The at least one bearing advantageously forms part of a damper 100 forming part of the mechanism. Preferably, for guiding the rotation of the resonator, the mechanism comprises two dampers 100 each comprising a resonator guide bearing. Preferably, the resonator pivots on either side of the shaft 2 by means of the two bearings. Also advantageously, mounting the resonator shaft in the guide bearings causes an elastic deformation of at least a part of the bearing. When the shaft is mounted in the guide bearings, the guide bearings are said to be preloaded.

[0025] Advantageously, the buffer or buffers 100 include a jewel that is returned to a stable position by the action of a spring and that is movable axially relative to the axis of the resonator against the action of the spring in case of a shock or acceleration that displaces the resonator relative to the jewel. A spring known as an anti-shock spring is designed to absorb the forces of the resonator axis through the jewel, and its function is to delimit the vibrations of the resonator axis, in particular the axial vibrations. In case of a shock, the forces experienced by the axis are absorbed by the anti-shock spring through the jewel. In conventional watchmaking, the anti-shock spring presses the jewel and the pivot jewel hard against a predefined inclination in the buffer body, so that the anti-shock spring has no axial effect on the resonator axis. The resonator axis is thus mounted with axial clearance in the buffer.

[0026] One or more of the shock absorbers 100 may include a pivot jewel, in which case in the event of an impact or acceleration that causes the resonator to move radially relative to its axis against the action of the guide bearing, the resonator may abut against the pivot jewel after the bearing has deformed to a certain limit.

[0027] Alternatively, one or more of the shock absorbers 100 may not include pivot jewels, in which case the bearings 1a; 1b; 1a'; 1b'; 1c' may replace the pivot jewels of shock absorbers known from the prior art.

[0028] In general, the bearings 1a; 1b; 1a'; 1b'; 1c' guide the shaft 2, in particular the resonator shaft, along the axis of rotation 21. The bearing comprises at least one pressing element 13a; 13b; 131a; 132a; 13a'; 13b'; 13c' which is arranged to constantly act on the shaft, in particular to exert a force on the shaft, radially or substantially radially with respect to the axis of rotation, said action may however be inclined with respect to the radial direction of the shaft 21 as a result of the coefficient of friction at the pressing element / shaft interface.

[0029] Preferentially, the action or actions are exerted perpendicular to the axis of rotation 21 of the shaft, so that the rotational guiding function may be separated from the function of absorbing axial loads. For example, the action or actions form an angle of less than 20° or less than 10° or less than 5° with respect to a plane perpendicular to the axis of rotation 21.

[0030] By "always exerting" it is meant that the action or actions are always exerted over time when the resonator is in a fixed position in the rest of the movement, regardless of the position of the movement in space, in particular regardless of the position of the resonator in space. Nevertheless, the contact between the pressure element and the axis is temporarily interrupted when the movement is subjected to an acceleration exceeding a certain threshold, for example a threshold of the order of 1 g corresponding to the strength of the gravitational field of the Earth, in particular a threshold between 0.1 g and 1 g. This threshold range advantageously allows the bearing to be optimally evaluated with respect to energy considerations, in particular with respect to the friction it causes with respect to the axis. Nevertheless, the acceleration threshold may be set to other values, in particular other values ​​of the order of 2 g, in particular more than 1 g, according to preference.

[0031] Advantageously, the strength of the torque resisting the movement of the resonator as a result of the action or actions exerted by the at least one pressure element on the shaft is constant or substantially constant, in particular constant over time, independent of the position in space of the movement, in particular independent of the position in space of the resonator, when the resonator is in position in the rest of the movement and while the resonator is running. Advantageously, the action or actions exerted by the at least one pressure element on the shaft is constant or substantially constant, in particular constant over time, independent of the position in space of the movement, in particular independent of the position in space of the resonator, when the resonator is in position in the rest of the movement.

[0032] The shaft portion guided by the bearing may be a pivot or a pivot shank. The pivot may present a cylindrical or frusto-conical cross section.

[0033] Preferentially, the bearing comprises at least one return element 12a; 12b; 12a'; 12b'; 12c' cooperating with at least one pressure element. It is thus at least one return element 12a; 12b; 12a'; 12b'; 12c' that returns at least one pressure element 13a; 13b; 131a; 132a; 13a'; 13b'; 13c' into contact with the axle 2. This at least one return element is advantageously elastically deformable. Thus, the return force that returns the at least one pressure element to bear against the axle is generated by the elastic deformation of the at least one return element. This at least one return element is defined or engineered to ensure that the contact is constant as long as the acceleration experienced by the watch is maintained below the above-mentioned acceleration threshold.

[0034] 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 more than three curved blades, in particular four or five curved blades, each curved blade having: at least one pressing element 13a for pressing against the shaft; a return element 12a for returning the at least one pressure element so as to press against the shaft; Configure.

[0035] Preferably, the blade is curved in the shape of a helix. The helix may in particular be defined by a polar equation in which the radius is proportional to the angle or in which the radius is proportional to a power of the angle. Alternatively, the blade may have any other shape, provided that it exhibits an appropriate stiffness. The blade may have a zigzag, straight or curved shape. The blade may be curved between its two ends by more than 180°, in particular up to 270°. The curved shape of the blade makes it possible to optimize the space that the blade occupies at a given size in order to obtain mechanical load characteristics and stiffness characteristics of the blade that are suitable for the application in question. The shape of the blade may be flat, in particular flat in a plane perpendicular to the axis of rotation of the bearing. The shape of the blade may also be non-flat. This allows the effective length of the blade to be increased.

[0036] In a first alternative of the first embodiment, which will be described below with reference to figures 2 to 4, the bearing mainly comprises a chassis 11a, in particular an annular chassis, and blades 14a, in particular three blades, extending towards the inside of the chassis. The blades extend, for example, from the inner surface of the annular chassis. Each blade has a convex and a concave surface. A first end of each blade is attached or fixed to the chassis. A second end of each blade is free. In the vicinity of each free second end, the concave surface may form a pressing element that presses against the shaft. Each pressing element is, for example, a part of the concave surface in the vicinity of the free end of the blade. In the illustrated alternative, the pressing element is formed on the surface by concave curved surfaces. The radius of curvature of these concave curved surfaces is greater than the radius of the shaft 2 that the bearing is intended to receive. For example, the radius of curvature of these concave curved surfaces at the height of the pressing element is greater than five times the radius of the shaft 2 that the bearing is intended to receive.

[0037] Each of the pressing elements is mechanically connected to the chassis via a return element, the return element being - a concave portion constituting the pressing element, - From the chassis, It consists of that part of the blade that separates.

[0038] The diameter of the inner surface of the chassis may correspond to 30 or even 40 times the diameter of the shaft 2 .

[0039] In a second alternative of the first embodiment, described below with reference to FIG. 5, the bearing differs from that described in the first alternative of the first embodiment in that the pressing element 131a extends perpendicular or substantially perpendicular to the free end of the blade in a plane perpendicular to the axis of rotation 21. The pressing element 131a in this alternative is thus a cylindrical section, arranged perpendicular or substantially perpendicular to the free end of the blade. This configuration supports, among other things, the positioning and stability of the pivot relative to the bearing. It can thus be ensured that the axis of rotation 21 of the shaft 2 is maintained in a predefined vicinity of its centered position in the bearing, even under the effect of significant loads of the resonator.

[0040] In a third alternative of the first embodiment, described below with reference to Fig. 6, the bearing differs from the bearing described in the second alternative of the first embodiment in that the pressing element 132a includes a ramp or hook 133a designed to limit the deformation of the return element 12a. This makes it possible to ensure that the axis of rotation 21 of the shaft 2 is maintained in a predefined vicinity of its centered position in the bearing, even under the effect of the considerable loads of the resonator. It also avoids the risk of the blade being damaged when the bearing is assembled, in particular when the shaft 2 is mounted in the bearing or during the operation of the movement when the resonator is in motion. The ramp is formed, for example, by an arm extending substantially perpendicular to the surface of the pressing element pressing against the shaft. The ramp is intended to cooperate with other adjacent pressing elements of the bearing. In Fig. 6 the various elements are illustrated in a configuration in which the ramp is inactive, i.e. in which the ramp does not cooperate by contact with the adjacent elements.

[0041] In a second embodiment, described below with reference to figures 7 to 10, the bearing differs from that described in the first embodiment in that the blade 14b is straight or rectilinear (rather than curved). In addition, in this embodiment, the surface of the pressing element that is in contact with the shaft 2 is planar. The flexible blade thus has the shape of a straight beam. Its cross section may be constant.

[0042] In this embodiment, the bearing comprises a ramp which limits the deformation of the return element. In particular, the blade maintains its proximity to the surface 16 of the chassis which constitutes the ramp. When the deformation of the return element reaches a certain degree, the blade comes into contact with said ramp, thus limiting the deformation. This avoids the risk of the blade breaking during assembly of the bearing, in particular when the axle 2 is mounted in the bearing, or during operation of the watch when the resonator is in motion, in particular in the event of a shock.

[0043] Whatever the alternative in the first two embodiments, the return element consists of part of the flexible blade.Preferentially, the various flexible blades are formed as a single piece, thus forming an integral bearing with the chassis.

[0044] Whatever the alternative in 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 pressing elements, are pressed rigidly against the shaft under the effect of the respective preload. In particular the blades, in particular the return elements, are elastically deformed when the shaft is guided in the bearing. The elastic deformation leads to a return force that tends to return the blades to their original position as the shaft is guided.

[0045] As illustrated in Fig. 3, when the watch is in a horizontal position (rotation axis 21 in a vertical position), each blade exerts the same force on the axis, ideally a force that is minimized as much as possible. Ideally, the force is suitable to induce a friction substantially the same as that exerted in a vertical position. The contact between the blade and the axis may be temporarily interrupted when the movement is subjected to an acceleration above a certain threshold. A threshold value between 0.5g and 1g advantageously means that the friction of the blade against the axis can be minimized as much as possible.

[0046] When the watch is in a horizontal position, the weight of the axle is theoretically not absorbed by the bearing. It is absorbed, for example, by the jewel. When the watch is in a vertical position (axis of rotation 21 horizontal), as shown in FIG. 4, the weight of the resonator is absorbed by the blade or blades of the bearing. This causes a small amount of movement (perpendicular to axis of rotation 21), which is advantageously similar or less than that known from conventional bearings. As a result of this movement, the blade or blades located above the axis exert a smaller force on the axis compared to the force exerted by the blades located below. As long as all the blades maintain contact with the axis, the sum of the strength of the blades' load on the axis remains essentially the same regardless of the position of the resonator. If the resonator is movable within the movement, the strength of the friction torque caused by the blades' load on the axis remains essentially the same regardless of the position of the resonator. This has the effect of harmonizing the quality factor of the resonator between the various horological device positions.

[0047] 10 partially illustrates the bearing without a shaft mounted thereon. In this configuration, the three blades define an inscribed circle of radius r0.

[0048] As the shaft is mounted in the bearings, the flexible blade is elastically deformed or prestressed over a distance rp-r0, where rp is the radius of the shaft at the point where the blade presses against the shaft.

[0049] Therefore, the preload force F0 of each flexible blade is F0 = k.(rp-r0) where k is the stiffness of each flexible blade.

[0050] A static force balance study has shown that the static friction torque C induced by the flexible blade on the axis of the resonator is constant or substantially constant whatever the position of the resonator in space, and this torque is given by: - the preload force F0 (as long as it is strictly positive on each blade), - the coefficient of friction η between the shaft and each of the flexible blades; - the radius of the axis rp, It has been shown that the dependence of

[0051] For this reason, whatever the position of the resonator, the static friction torque C is equal or substantially equal to the static friction torque CH that the flexible blade induces on the axis of the resonator when the watch is in a horizontal position (shaft 2 and axis of rotation 21 are arranged vertically). In the configuration of the resonator illustrated in Figure 9 (and assuming that the weight P is oriented exclusively along the axis of rotation of the shaft), the torque CH can be expressed as follows: CH=3.η.F0.rp or CH=3.η.k(rp-r0).rp For this reason, C=3.η.F0.rp or C=3.η.k(rp-r0).rp.

[0052] This value C is constant or substantially constant whatever the position of the clock, and therefore has the effect of cancelling out the quality factor between the various positions of the oscillator.

[0053] As an example, Fig. 18 shows a graph of various quality factors FQ based on the amplitude of oscillation of the oscillator and on the spatial position of a small clock fitted with an oscillator rotated by two bearings, as shown in Fig. 7. It can be seen that the quality factor FQ is standardized regardless of the position of the resonator, and is significantly standardized compared to the quality factor FQ of the same resonator, but rotated conventionally, as shown in Fig. 17.

[0054] The preload force F0 can be minimized as much as possible and according to the chosen resonator to optimize the energy required to maintain the oscillation. The minimum strength of the force Fm is defined by the limit condition where the force Fi (F2 in FIG. 8) generated by one of the flexible blades is counterbalanced by the weight of the resonator (maximum acceleration 1 g). Calculations show that, at constant friction η, the scenario: F0>2.P / 3 where P is the force exerted by the resonator on the bearing.

[0055] By respecting this criterion, F0 can be minimized as much as possible in order to produce the smallest static friction torque while harmonizing the friction torques at all horizontal and vertical positions.

[0056] Specifically, the stiffness k of each of the flexible blades is given by: k>2.P / (3.(rp-r0)) The criteria must be met.

[0057] Whatever the alternatives in the first two embodiments, the cross section of the blades may be constant or not. Each of the blades may be made up of several blades, which may be joined or not, in order to optimize and differentiate the stiffness according to the various movements and positions of the resonator. For example, the embodiment may minimize the radial force pressing against the shaft with a view to minimizing the frictional forces against the shaft and at the same time ensuring that the rotating shaft is centered in the bearing.

[0058] Whatever the alternatives in the first two embodiments, - the blade or blades extend parallel or substantially parallel to the pressing element in the vicinity of the pressing element, and / or perpendicular or substantially perpendicular to the axis of rotation in the vicinity of the pressing element, or The blade or blades extend perpendicular or substantially perpendicular to the pressing element in the vicinity of the pressing element and / or perpendicular or substantially perpendicular to the axis of rotation in the vicinity of the pressing element.

[0059] In either the first or second embodiment, the blade, or more generally the bearing, may be made for example of nickel, a nickel-phosphorus alloy, or alternatively of silicon and / or coated silicon (silicon oxide, silicon nitride, etc.). The parts may preferably be manufactured by electroforming or etching. Alternatively, the parts may be machined by spark discharge machining.

[0060] In a third embodiment described below with reference to Figures 14 to 16, the bearing comprises at least one radial or substantially radial projection 14a', 14b', each projection having: - at least one pressing element for pressing against the shaft; - a return element for returning the at least one pressure element to press against the shaft; Includes.

[0061] For this reason, preferably, the bearing may comprise a ring presenting a shape comprising several projections or protrusions extending from the ring surface towards the ring's axis of rotation, in particular towards the ring's axis of rotation. Preferably, the ring comprises at least two projections. The ring may comprise, in particular, two or three or four or five or six projections.

[0062] Preferably, the bearing comprises a ring made of an elastomeric material, which may be made of natural rubber or a synthetic rubber such as neoprene, polybutadiene, polyurethane, or alternatively silicone.

[0063] Alternatively, the ring may present a constant cross section. In that case, the ring may present a pressing element comprising a continuous surface which comes to press against the shaft over all or a large part of its circumference, for example over 240° or over 270° or over 300°. In that alternative, the bearing comprises a single pressing element which bears against the shaft. The pressing element consists of a surface in contact with the shaft. The annular part of the ring situated between the surface in contact with the shaft and the large diameter surface of the ring constitutes a return element, in this case the single return element.

[0064] In a first alternative of the third embodiment described below with reference to figure 14, the bearing 1a' comprises three projections 14a'. Each projection comprises a pressing element 13a' which presses against the shaft and a return element 12a' which returns the pressing element into contact with the shaft. The pressing element consists of the surface of the projection which is in contact with the shaft. The return element consists of the projection material which connects the pressing element to the rest of the ring 11a' which constitutes the chassis and which presents a constant cross section. The projections are protrusions or embosses filled with material.

[0065] In a second alternative of the third embodiment, described below with reference to figure 15, the bearing differs from the first alternative of the third embodiment of the bearing in that the projections are protrusions or embosses provided with incisions 91. The bearing may thus comprise at least one radial or substantially radial projection, each projection comprising at least one pressing element for pressing against the shaft and one return element for returning the at least one pressing element to press against the shaft, the return element or elements comprising an incision. "Incision" is understood to mean in particular any cavity produced by any technique other than cutting, in particular by casting. The incisions 91 allow for adjustment of the stiffness of each of the projections.

[0066] In a third alternative of the third embodiment described below with reference to FIG. 16, the bearing differs from the first alternative of the third embodiment or the second alternative of the third embodiment in that the ring is mechanically connected, in particular fixed and in particular overmolded, to a band 11c′ constituting the chassis.

[0067] In any embodiment and in any alternative, the at least one return element and the at least one pushing element are preferably manufactured in one piece.

[0068] In the described alternatives and embodiments, the bearing exhibits three return elements and three pressure elements. However, in any embodiment and in any alternative, the bearing may exhibit a number of return elements other than three and a number of pressure elements other than three. In particular, in any embodiment and in any alternative, the bearing may exhibit 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 pressure elements. By preference, the bearing exhibits the same number of return elements as pressure elements.

[0069] Whatever the embodiment or alternative, the pressing surface of each pressing element pressing against axis 2 may be planar or concave or convex. In particular, all pressing surfaces may be planar or concave or convex.

[0070] In any embodiment and in any alternative, the chassis, in particular the annular chassis, may be manufactured as a single piece or as several independent pieces, in particular as many as the return elements. If the blades are manufactured independently of one another, they are each fixed to a base 111a. The base is advantageously provided with positioning elements and possibly with adjustment elements, in particular centering elements such as holes. The positioning elements make it possible to define the axis of rotation of the bearing. Such an embodiment including a base is illustrated in FIG. 12. The positioning elements cooperate, for example, with pins.

[0071] In any embodiment or alternative, the bearing may be provided with a means for mounting the bearing. For example, the chassis may include a split ring, as shown in Figure 13, where the split is present to allow the ring to be elastically deformed and to properly position the blade during assembly. The chassis may also include a continuous ring, as shown in Figure 11.

[0072] In any embodiment or alternative, the bearing may include a ramp to limit deformation of the return element.

[0073] Whatever the embodiment and alternative, the pushing elements and / or the return elements are preferably arranged angularly uniformly around the axis of rotation 21 .

[0074] The solution described aims to overcome the problem of lead differences between positions by proposing a bearing configured to generate an essentially constant force on the axis of the resonator, regardless of the position of the resonator. To achieve this, the bearing has the feature that it is provided with at least one return element designed to apply a substantially radial force to the axis of the resonator, regardless of the position of the resonator.

[0075] The bearing is provided with at least one return element designed to apply a substantially radial force to the shaft in order to induce an essentially constant force between the shaft and the bearing regardless of the position of the watch.

[0076] This reduces the difference in advance between positions to a strict minimum, so that the quality factor of the resonator remains constant or substantially constant regardless of the position of the resonator, optimizing the chronometric performance of the movement.

[0077] The return means preferably have the function of supporting the shaft of the resonator and of positioning the shaft at least in the transverse plane of the bearing.

[0078] Whatever the embodiment, the bearings may be incorporated into a shock absorber, particularly a shock absorber of conventional construction.

[0079] It is noted that in the shock absorber according to the invention, the axial damping function may be separated from the radial damping function, in particular the axial damping function is mainly provided by the conventional jewel and the conventional shock spring, while the radial damping function is provided by the shaft. [Explanation of symbols]

[0080] 1a Bearing 2-axis 11a chassis 12a Return element 13a Pressing element 14a Blade 100 buffer 110 Clock Mechanism 120 Clock Movement 130 Clock

Claims

1. A clock resonator axis (2), a bearing (1a; 1b; 1a'; 1b'; 1c') for guiding a portion (2) of said clock resonator shaft (2) around an axis of rotation (21), The clock resonator shaft (2) is arranged and rotates in the bearing, said bearing comprises at least one pressure element (13a; 13b; 131a; 132a; 13a'; 13b'; 13c') arranged to constantly exert an action on said timepiece resonator shaft, radially or substantially radially with respect to said axis of rotation, said bearing comprises a chassis (11a; 111a; 112a; 11b; 112b; 11a'; 11b'; 11c'), said pressure element is mechanically connected to said chassis via a return element, and said chassis is manufactured in one piece or in several independent parts, and said bearing comprises a ramp (133a) limiting the deformation of said return element, and said pressure element and said return element are angularly uniformly arranged around said axis of rotation (21), A clock mechanism (110).

2. 2. A timepiece mechanism (110) according to claim 1, wherein said bearing comprises at least one return element (12a; 12b; 12a'; 12b'; 12c') cooperating with said at least one pressure element.

3. 3. The timepiece mechanism (110) according to claim 2, wherein said at least one return element (12a; 12b; 12a'; 12b'; 12c') and said at least one pressure element are formed in one piece.

4. A timepiece mechanism (110) according to any one of claims 1 to 3, wherein the bearing comprises at least two pressing elements (13a; 13b; 131a; 132a; 13a'; 13b'; 13c') for pressing a timepiece resonator axis around the rotation axis (21).

5. A timepiece mechanism (110) according to any one of the preceding claims, wherein said bearing comprises at least two return elements and at least an equal number of pressure elements.

6. A timepiece mechanism (110) according to any one of the preceding claims, wherein each of said at least one pressure element comprises at least one planar or concave or convex pressure surface (9).

7. The bearing comprises at least one blade (14a; 14b), the blade comprising: at least one pressing element (13a; 13b; 131a; 132a) for pressing against said timepiece resonator shaft; A timepiece mechanism (110) according to any one of the preceding claims, comprising a return element (12a; 12b) for returning said at least one pressure element so as to bear against said timepiece resonator shaft.

8. The portion of the blade or blades other than the pressing element extends parallel or substantially parallel to the pressing element in the vicinity of the pressing element, or extends perpendicular or substantially perpendicular to the rotation axis in the vicinity of the pressing element. A clock mechanism (110) according to claim 7.

9. A timepiece mechanism (110) according to claim 7 or 8, wherein said blade or blades extend at least substantially straight, or said blade or blades extend curved.

10. A timepiece mechanism (110) according to any one of the preceding claims, comprising a buffer (100) including said bearing (1) and a jewel.

11. 11. A timepiece mechanism (110) according to any one of claims 1 to 10, wherein the timepiece mechanism comprises a resonator including a balance, or the timepiece mechanism comprises a resonator whose shaft part or pivot shank is guided in the bearing, and wherein the at least one return element is preloaded.

12. A clock resonator shaft (2), a bearing (1a; 1b; 1a'; 1b'; 1c') for guiding a portion (2) of said clock resonator shaft (2) around an axis of rotation (21), The clock resonator shaft (2) is arranged and rotates in the bearing, said bearing comprises at least one pressure element (13a; 13b; 131a; 132a; 13a'; 13b'; 13c') arranged to constantly exert an action on said timepiece resonator shaft, radially or substantially radially with respect to said axis of rotation, The bearing comprises at least one radial or substantially radial projection (14a'; 14b'), each projection having: at least one pressing element (13a'; 13b'; 13c') for pressing against said timepiece resonator shaft, a return element (12a'; 12b'; 12c') for returning said at least one pressure element so as to bear against said timepiece resonator shaft; A timepiece mechanism (110) according to any one of claims 1 to 6, comprising:

13. A clock mechanism (110) as described in claim 12, wherein the bearing includes at least one return element (12a; 12b; 12a'; 12b'; 12c') cooperating with the at least one pressure element.

14. A clock mechanism (110) as described in claim 13, wherein the at least one return element (12a; 12b; 12a'; 12b'; 12c') and the at least one pressure element are formed integrally.

15. A clock mechanism (110) as described in any one of claims 12 to 14, wherein the bearing includes at least two pressing elements (13a; 13b; 131a; 132a; 13a'; 13b'; 13c') for compressing the clock resonator axis around the rotation axis (21).

16. A clock mechanism (110) as described in any one of claims 12 to 15, wherein the bearing includes at least two return elements and at least an equal number of pressing elements.

17. A clock mechanism (110) as described in any one of claims 12 to 16, wherein each of the at least one pressing element includes at least one planar or concave or convex pressing surface (9).

18. The bearing comprises a chassis (11a; 111a; 112a; 11b; 112b; 11a'; 11b'; 11c'), the pressing element is mechanically connected to the chassis via a return element, and the chassis is manufactured as a single piece or as several independent parts, and the bearing comprises a slope (133a) limiting deformation of the return element, and the pressing element and the return element are angularly uniformly arranged around the rotation axis (21), A clock mechanism (110) according to any one of claims 12 to 17.

19. A clock mechanism (110) as described in any one of claims 12 to 18, comprising a shock absorber (100) including the bearing (1) and a jewel bearing.

20. A clock mechanism (110) as described in any one of claims 12 to 19, wherein the clock mechanism comprises a resonator including a balance, or the clock mechanism comprises a resonator whose shaft part or pivot shank is guided in the bearing, and the at least one return element is pre-stressed.

21. The chassis is an annular chassis. A timepiece mechanism (110) according to any one of claims 1 to 11 and 18 to 20.

22. A clock movement (120) comprising a clock mechanism according to any one of claims 1 to 21.

23. A timepiece (130) comprising a timepiece mechanism according to any one of the preceding claims.

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