CH720831A2 - Bearing for watch part - Google Patents

Abstract

One aspect of the invention relates to a bearing (1) for a timepiece comprising a bearing body (2) provided with a through opening (8), said opening (8) comprising a compact assembly (10) under stress comprising: – a first elastic member (3) mounted in a first orifice (9a) of the through opening (8); – a second elastic member (6) arranged between the first elastic member (3) and a second orifice of said opening (8); – a pivot element (5) provided for pivoting an axis of a watch component, said element (5) being arranged in a central zone of the second elastic member (6) while being positioned opposite the second orifice through which said axis of said component is capable of being introduced into said opening (8), and – a counter-pivot element (4) interposed between the first and second elastic members (3, 6) which is provided for receiving an end portion of said axis of the component, said counter-pivot element (4) consisting of a central portion (13a) and a peripheral portion (13b), the central portion (13a) comprising a cavity in which a portion of the pivot element (5) is capable of being arranged and said peripheral portion (13b) comprising a contact zone (23) configured to bear on an entire periphery of a flat upper face of the second elastic member (6).

Description

Technical field of the invention

[0001] Embodiments of the present invention relate to a bearing for a timepiece, in particular a shock-absorbing bearing, for an axis of a timepiece component. The invention also relates to a timepiece movement provided with such a bearing. The invention further relates to a timepiece comprising such a bearing and/or such a timepiece movement.

Technological background

[0002] In timepieces, the axes of the watch components generally have pivots at their ends which rotate in bearings mounted in blanks, such as the plate or in bridges of watch movements of these parts. For certain watch components, in particular balances, it is customary to equip the bearings with a shock-absorbing mechanism. Indeed, as the axis pivots of these balances are generally thin and the masses of these balances are relatively high, the pivots can break under the effect of a shock in the absence of shock-absorbing mechanisms.

[0003] In the prior art, a conventional shock absorber bearing commonly comprises a pad such as a pierced stone provided with a through hole forming an axial and radial guide element for the pivot. Such a stone is driven into a bearing support, commonly called a setting, on which is mounted a counter-pivot stone forming an axial stop for the pivot. This setting is designed to transform a radial shock into an axial shock. Such a setting is held in abutment against the bottom of a bearing body by elastic means, generally a shock absorber spring, arranged to exert an axial stress on the upper part of the counter-pivot stone. This pivot of the axis is inserted into the through hole of the pierced stone. Such a bearing makes it possible to absorb shocks, the assembly formed by the setting, the pierced stone, and the counter-pivot stone, being able to move thanks to the shock absorber spring.

[0004] However, one of the major drawbacks of such a bearing is linked to its lack of robustness, due in particular to the aging of the lubricant it contains or to its wear over time, thus altering its operation which then becomes less reliable. As a result, such a bearing no longer guarantees perfect radial recentering of the balance shaft in the event of an impact, this recentering often being random. Indeed, the problem here lies in the fact that the rate of the movement is adjusted at a time T, in a given anti-shock configuration. Following an impact, the configuration of the bearing changes due for example to imperfect recentering and the rate adjustment carried out previously is then no longer optimal. In other words, the position of the balance shaft directly impacts the rate of the movement, it is therefore necessary for better chronometric stability to overcome this recentering defect.

Summary of the invention

[0005] One of the aims of the invention is to propose a bearing for a timepiece of small size allowing the axis of a watch component to be repositioned extremely efficiently.

[0006] Another aim of the invention is to propose a bearing making it possible to repeatably position the axis of a watch component.

[0007] Another aim of the invention is to propose a bearing having a small footprint.

[0008] For this purpose, the invention relates to a bearing for a timepiece comprising a bearing body provided with a through opening, said opening comprising a compact assembly under stress comprising: – a first elastic member mounted in a first orifice of the through opening; – a second elastic member arranged between the first elastic member and a second orifice of said opening; – a pivot element provided for pivoting an axis of a watch component, said element being arranged in a central zone of the second elastic member while being positioned opposite the second orifice through which said axis of said component is capable of being introduced into said opening, and – a counter-pivot element interposed between the first and second elastic members which is provided for receiving an end portion of said axis of the component, said counter-pivot element consisting of a central portion and a peripheral portion, the central portion comprising a cavity in which a portion of the pivot element is capable of being arranged and said peripheral portion comprising a contact zone configured to bear on an entire periphery of a flat upper face of the second elastic member.

[0009] In other embodiments: – the central portion and the peripheral portion respectively form a top (13a) and a base of the counter-pivot element; – the counter-pivot element is mounted axially movable in the through opening relative to an axis of revolution of this opening; – the central portion of the counter-pivot element is configured to be inserted into the second orifice of the through opening during an impact likely to be sustained by the timepiece; – the peripheral portion of the counter-pivot element comprises a stop zone configured to cooperate with the first elastic member during an impact likely to be sustained by the timepiece; – the portion of the pivot element arranged in the cavity projects from the central zone of the second elastic member, this portion comprising an external surface which is positioned in the vicinity of a bottom of the cavity; – the first elastic member is configured to deform essentially axially relative to an axis of revolution (of the through opening; – the first elastic member comprises elements for fixing this member in the through opening and constraint elements intended to press on the central part of the counter-pivot element and connecting elements connecting the constraint elements and the fixing elements together; – the second elastic member comprises a connecting part of this member in the through opening and a fixing part of the pivot element in a central zone of this member, said connecting and fixing parts being connected to each other by at least one elastic element of this member; – the second elastic member is fixedly mounted in the bearing body; – the second elastic member is configured to deform essentially radially relative to an axis of revolution of the through opening; – the bearing body, the through opening, the first and second elastic members, the counter-pivot element and the pivot element have axes of revolution which coincide with a central axis of the bearing.

[0010] Another aspect of the invention relates to a watch movement provided with such a bearing.

[0011] Another aspect of the invention relates to a timepiece comprising such a timepiece movement.

Brief description of the figures

[0012] Other features and advantages of the invention will become more clearly apparent upon reading the following description of a particular embodiment of the invention, given as a simple illustrative and non-limiting example, and the appended figures, among which: – Figure 1 is a perspective view of a bearing for a timepiece, according to an embodiment of the invention; – Figure 2 is a top view of the bearing shown in Figure 1, according to the embodiment of the invention; – Figure 3 is a sectional view along an axis III-III of the bearing shown in Figure 2, according to the embodiment of the invention, and – Figure 4 is an exploded view of all the parts forming the bearing, according to the embodiment of the invention.

Detailed description of the invention

[0013] Figures 1 to 4 illustrate an embodiment of a bearing 1 for a timepiece such as a watch, in particular a wristwatch. Such a bearing 1 may be part of a timepiece mechanism of a timepiece movement such as an electronic movement or a mechanical movement. For example, the timepiece mechanism may be a balance-spring type oscillator provided with a balance and a spring.

[0014] This bearing 1 also called "watch bearing" or "shockproof bearing" or "shock absorber bearing", is particularly suitable for the pivoting of an axis, in particular an axis pivot, made of ceramic or glass. Such an axis also called "rotation axis" or "pivot axis" or "shaft" can be an axis of a watch component also called "axis of a rotating mobile" such as a balance wheel tigeron when the watch mechanism is an oscillator.

[0015] Such a bearing 1 is effectively configured to guide in rotation around the central axis A1 of the bearing 1 otherwise called axis A1 of the mounted bearing, the axis of the watch component and also to stop this axis in translation, in particular to limit its movements in axial and/or radial translation relative to the axis A1.

[0016] It will be noted that the guidance of the axis of this watch component is also that of the component itself, which then sees its movements relative to the axis A1 limited in axial and/or radial translation thanks to this bearing 1.

[0017] Such a bearing 1 is intended to be assembled or secured to a blank of the watch movement such as a bridge, for example a balance bridge, or even a plate. This bearing 1 can alternatively be formed directly in the body of a plate or a bridge, for example by machining.

[0018] With reference to FIG. 4, the bearing 1 comprises a bearing body 2 which is configured to receive a compact assembly 10 consisting of the following components: a pivot element 5, a counter-pivot element 4 and first and second elastic members 3, 6.

[0019] This bearing body 2 comprises a through opening 8 also called a “central through opening” extending in a direction parallel to that of an axis of revolution A2 of this bearing body 2 also called the axis of the block. Such a through opening 8 comprises at each of its ends first and second orifices 9a, 9b. It will be noted that the first orifice 9a has a section which is preferably greater than the section of the second orifice 9b. As we will see later, the first orifice 9a is configured to participate in the mounting of the first elastic member 3 in the through opening 8 and the second orifice 9b is configured for its part to allow the introduction of the axis of the watch component into this same opening 8.

[0020] In this bearing body 2, the through opening 8 comprises an axis of revolution A3 also called the axis of the opening 8, which coincides with the central axis A1 of the bearing 1. Such a through opening 8 has a geometry of revolution around this axis A3 which forms a housing or even an enclosure of this bearing body 2. It will be noted that this housing corresponds to the volume defined in the bearing body 2 by an internal peripheral wall 20 of the through opening 8 visible in FIG. 4. In this configuration, such a housing therefore extends between the first and second orifices 9a, 9b which are part of such a housing.

[0021] In this bearing 1, the through opening 8 is configured to receive or to participate in the arrangement, or in the mounting, of the compact assembly 10 in the bearing body 2. In this configuration, the compact assembly 10 comprises mounting zones 11a, 21a, 22a, 22b provided to cooperate with the internal peripheral wall 20 of the through opening 8 in order to ensure the arrangement of this compact assembly 10 in the bearing body 2. Such mounting zones 11a, 21a, 22a, 22b are included in/on the first and second elastic members 3, 6 of this assembly 10. In a variant, these mounting zones 11a, 21a, 22a, 22b are included exclusively in/on the first and second elastic members 3, 6. In other words, these mounting zones 11a, 21a, 22a, 22b are provided in the bearing body 2. 22a, 22b are the only parts of this compact assembly 10 which achieve/ensure its mounting in the bearing body 2 to form the bearing 1. As we will see later, these mounting zones 11a, 21a, 22a, 22b cooperate with this bearing body 2 by bearing and/or being fixed to this body 2.

[0022] In this assembly, the pivot element 5, the counter-pivot element 4, the first elastic member 3 and the second elastic member 6 respectively comprise central axes A4, A5, A6, A7. These axes referenced A4, A5, A6, A7 are merged with the axes A1, A2 A3 respectively of the bearing 1, of the bearing body 2 and of the through opening 8 when the compact assembly 10 is mounted in the bearing body 2.

[0023] As we have mentioned, this compact assembly 10 is formed by the following succession of components: the first elastic member 3, the counter-pivot element 4, the second elastic member 6 comprising the pivot element 5.

[0024] The first elastic member 3, which is for example an elastic element of the return spring type, is provided to elastically return and adequately axially replace the counter-pivot element 4 and thereby the axis of the watch component within the opening 8 of the bearing body 2 following a substantially axial shock suffered by the timepiece, in particular suffered by the watch movement of this part. In other words, the first elastic member 3 is configured to deform essentially axially relative to the axis of revolution A3 of the through opening 8. In other words, this first member 3 is configured to perform an axial repositioning of the axis of the watch component always in the same place by being constructed so as to absorb substantially axial shocks. It is therefore understood that this member 3 is configured to place axially relative to the axis of revolution referenced A3, the axis of the watch component in its initial or rest position in response to these shocks.

[0025] Such a first elastic member 3 is secured or fixed to the bearing body 2. More precisely, this first elastic member 3 is mounted in the first orifice 9a of the through opening 8. To do this, this first elastic member 3 comprises at least one connecting element 11c, at least one constraint element 11b and at least one fixing element 11a which are connected to each other.

[0026] More specifically, this member 3 comprises fixing elements 11a also called “securing elements” which are configured to be arranged in notches 12 formed in the first orifice 9a of the opening 8. With reference to FIG. 4, this first member 3 comprises two fixing elements 11a. Each fixing element 11a is configured to be arranged in the notch 12 provided in the through opening 8 in order to participate in the mounting of this first elastic member 3 in this opening 8. It will be noted that these fixing elements 11a are part of the mounting zones 11a, 21a, 22a, 22b of the assembly 10 in the bearing body 2 mentioned above.

[0027] The first elastic member 3 also comprises constraint elements 11b which are in contact with the counter-pivot element 4. More precisely, the constraint elements 11b are intended to press on a central part 13a of the counter-pivot element 4, in particular on a vertex 13a of this counter-pivot element 4. These constraint elements 11b are configured to apply to this counter-pivot element 4 an essentially axial return force, in particular an axial and elastic force. With reference to FIG. 4, it will be noted that this first elastic member 3 preferably comprises two constraint elements 11b.

[0028] The first elastic member 3 also comprises connecting elements 11c connecting the constraint elements 11b and the fixing elements 11a together. In this first elastic member 3, these connecting elements 11c are two in number as can be seen in FIG. 4.

[0029] In this compact assembly 10, the counter-pivot element 4 is provided to receive an end portion (or an end) of the axis of the watch component corresponding to the end of the pivot, or to constitute a stop for the end portion of this axis. In the through opening 8, the counter-pivot element 4 is interposed between the first and second elastic members 3, 6. Such a counter-pivot element 4 is mounted axially and radially movable in such a through opening 8 relative to the axis of revolution A3 of this opening 8.

[0030] This counter-pivot element 4 consists of the central part 13a and a peripheral part 13b as well as internal and external faces 14a, 14b. It will be noted that in this element 4, the central part 13a is surrounded by the peripheral part 13b. Such a counter-pivot element 4 comprises a step zone 13c which connects the central and peripheral parts 13a, 13b together and which is visible on the external surface 14b of this element 4 illustrated in FIGS. 3 and 4. In this configuration, such central and peripheral parts 13a, 13b respectively form the top 13a and a base 13b of the counter-pivot element 4.

[0031] In the inner face 14a of this counter-pivot element 4, the central part 13a comprises a cavity 15, visible in FIG. 3, in which a part of the pivot element 5 is likely to be arranged as will be seen later. In this inner face 14a, the peripheral part 13b comprises a contact zone 23 configured to bear directly on a periphery of a flat upper face of the second elastic member 6. In a variant, the contact zone 23 is configured to bear directly on the entire periphery of the flat upper face of the second elastic member 6. It will be noted that such a cavity 15 can be produced by machining, in particular by conventional machining with a diamond tool or by laser machining.

[0032] As mentioned above, the central portion 13a and the peripheral portion 13b respectively form the top 13a and the base 13b of this counter-pivot element 4. This top 13a is configured/shaped to be inserted into the first elastic member 3 in particular in a space defined in the latter which is delimited by the connecting elements 11c of this first elastic member 3 and this, in particular during a substantially axial impact likely to be suffered by the timepiece. With regard to this base 13b, it is configured to form a stop zone of the counter-pivot element 4 by cooperating with the first elastic member 3 during such an impact. Indeed, such a stop zone is defined on a portion of the external face 14b of the counter-pivot element 4 located on this base 13b. In this configuration, this stop zone is able to cooperate with the connecting elements 11c and the fixing elements 11a in order to limit the axial displacement of the axis of the watch component during an impact, in particular a substantially axial and strong impact.

[0033] Such a counter-pivot element 4 may be, for example, a counter-pivot stone made of synthetic precious stone or of non-mono- or polycrystalline material, such as ruby or zirconia, an element made of metallic material or of silicon-based material (such as mono- or polycrystalline silicon, its oxide, its nitride, its carbide, also mono- or polycrystalline).

[0034] In this compact assembly 10, the pivot element 5 is provided to pivot the axis of the watch component. This pivot element 5 comprises a central hole 17 for receiving this axis of the watch component and in particular the end part of this axis. This pivot element 5 is arranged in a central zone of the second elastic member 6 while being positioned opposite the second orifice 9b through which the axis of the watch component is capable of being introduced into said through opening 8. Such a pivot element 5 comprises upper 18a, lateral 18b and lower 18c surfaces, with the lateral surface 18b connecting these upper and inner surfaces 18a, 18c together. In this configuration, the upper surface 18a of this element 5 is arranged opposite the internal face 14a of the counter-pivot element 4 and the lower surface 18c opposite the second orifice 9b. More specifically, this pivot element 5 comprises a projecting portion of the second elastic member 6 which is arranged in the cavity 15 of the counter-pivot element 4 with the upper surface 18a which is positioned in the vicinity of a bottom 16 of this cavity 15.

[0035] Such a pivot element 5 also called a “cushion”, may be a conventionally drilled stone made of synthetic precious stone or non-mono- or polycrystalline material, such as ruby or zirconia or made of a silicon-based material (such as mono- or polycrystalline silicon, its oxide, its nitride, its carbide, also mono- or polycrystalline) or even be a ring made of metallic material.

[0036] In this compact assembly 10, the second elastic member 6 is arranged/fixedly mounted in the through opening 8 and therefore in the bearing body 2. In this through opening 8, this second elastic member 6 is arranged on a bearing surface 19 included on the internal peripheral wall 20 of this opening 8. It will be noted that this bearing surface 19 is located at the bottom of the orifice 9a and is orthogonal to the surface of the internal peripheral wall 20.

[0037] In this assembly 10, the second elastic member 6 is configured to deform essentially radially relative to the axis of revolution A3 of the through opening 8. In other words, this second member 6 is configured to achieve a radial recentering of the axis of the watch component always at the same location while being constructed so as to absorb radial shocks.

[0038] More specifically, this second elastic member 6 comprises a connecting portion 21a to the inner peripheral wall 20 of the through opening 8, and a fixing portion 21b of the pivot element 5 in the central zone of this member 6, said connecting and fixing portions 21a, 21b being connected to each other by at least one elastic element 21c of this second elastic member 6. It will be noted that the connecting and fixing portions 21a, 21b are rigid portions of this member 6 in comparison with the elastic element 21c. These connecting and fixing portions 21a, 21b are capable of deforming elastically when they are under stress.

[0039] Said at least one elastic element 21c is configured to ensure the radial deformation of the second elastic member 6 by controlling the movement of the fixing part 21b relative to the connecting part 21a during shocks suffered by the movement. In other words, the elastic element 21c is configured to place radially relative to the axis of revolution referenced A3, the connecting part 21a or the pivot element 5 or even the axis of the watch component in its initial or rest position in response to shocks.

[0040] This second elastic member 6 also comprises flat upper and lower faces which are preferably substantially parallel to each other.

[0041] The connecting portion 21a forms an outer peripheral wall of this second elastic member 6. In this configuration, when the second elastic member 6 is mounted in the through opening 8, a lateral surface 22a of this peripheral wall, and therefore of this connecting portion 21a, bears on all or parts of the inner peripheral wall 20 of this opening 8. Indeed, this connecting portion 21a is configured to deform elastically when the second elastic member 6 is inserted into the through opening 8. Thus, this connecting portion 21a is then able to bear on the inner peripheral wall 20 of the opening 8 from its lateral surface 22a. For example, the second elastic member 6 can be inserted by driving into this through opening 8.

[0042] This connecting part 21a also comprises a contact surface 22b which is configured to cooperate with the bearing surface 19 included in the through opening 8. With reference to the example cited above, it will be noted that the second elastic member 6 is inserted by driving into the through opening 8 until it comes into abutment against the bearing surface 19 of the through opening 8 via the contact surface 22b of the connecting part 21a. It will be noted that this contact surface 22b is included on the flat lower face of this second member 6.

[0043] It is therefore understood that such a connecting part 21a makes it possible to arrange/mount the second elastic member 6 fixed in the through opening 8. In other words, this connecting part 21a contributes to ensuring a fixing or a holding of the second elastic member 6 which is sufficiently strong to avoid any relative axial, radial and/or angular displacement of this second member 6 with respect to the axis of revolution A3 of the opening 8.

[0044] It will be noted that this connecting part 21a is part of the mounting zones 11a, 21a, 22a, 22b of the compact assembly 10 in the bearing body 2. In other words, the contact surface 22b and the lateral surface 22a of this connecting part 21a are included in these mounting zones 11a, 21a, 22a, 22b.

[0045] The connecting portion 21a also comprises a support surface 22c forming/comprising the periphery of the flat upper face which is configured to cooperate with the contact zone 23 of the counter-pivot element 4. Indeed, the base 13b of the counter-pivot element 4 is able to bear directly on this support surface 22c. In the connecting portion 21a, this support surface 22c is positioned above or directly above the contact surface 22b. In addition, this support surface 22c is substantially parallel to the contact surface 22b.

[0046] As we have mentioned, the second elastic member 6 also comprises a fixing part 21b of the pivot element 5 in the central zone of this second member 6. This fixing part 21b forms an inner peripheral wall of this second elastic member 6. The pivot element 5 may be a part added to this second member 6 with its lateral surface 18b which is configured to be fully or partially connected to this inner peripheral wall. Such a connection may be made by driving, gluing or even welding.

[0047] It will be noted that in a variant, this pivot element 5 can be an integral part of this second member 6 by being integral with the fixing part 21b. In this configuration, the central zone of this second member 6 is then considered as being/forming this pivot element 5.

[0048] This second elastic member 6 can be produced by microfabrication, by implementing a deep reactive ion etching process (usually referred to by its English acronym “DRIE”) for a member 6 comprising in particular silicon, or by a Liga process such as UV-Liga for a member 6 based, for example, on nickel.

[0049] Thus, such a bearing 1 according to the invention has a small/reduced bulk compared with bearings of the state of the art and this, without consequence on the operation of this bearing 1. Such a reduced bulk is notably conferred by the compact assembly 10 formed by the first and second elastic members 3, 6 and the counter-pivot and pivot elements 4, 5, and more precisely by: – the particular shape of the counter-pivot element 4 which allows a displacement of the central part 13a of this element 4, here the top 13a, in the first orifice 9a of the through opening 8 of the bearing body 2; – the particular shape of the counter-pivot element 4 which allows a support of its base 13b directly on the flat upper face of the second elastic member 6 vertically above the bearing surface 19; – the presence of a cavity 15 in the internal face 14a of the counter-pivot element 4 in which a part of the pivot element 5 is likely to be arranged; – the positioning of the pivot element 5 in a central zone of the second elastic member 6, with a part of the body of this element 5 which is included in the thickness of this second elastic member 6.

[0050] It will be noted that in this bearing 1, the counter-pivot element 4, by bearing on the upper face of the second elastic member 6, exerts only an axial and elastic force over the entire periphery of the flat upper face of this second elastic member 6 under the action of the constraint elements 11b bearing on the top 13a of the counter-pivot element 4. This force is then applied by the contact zone 23 of the counter-pivot element 4 on the support surface 22c forming said periphery and this, vertically above the bearing surface 19 of the through opening 8.

[0051] It should further be noted that a substantially axial impact should be understood to mean an impact that is “strictly axial” or “essentially axial” or “partly axial”. Similarly, a substantially radial impact should be understood to mean an impact that is “strictly radial” or “essentially radial” or “partly radial”.

[0052] Furthermore, in this description, “substantially parallel” means “strictly parallel or essentially parallel”.

[0053] Thus, such a bearing 1 helps to ensure axial and radial recentering/repositioning of the axis of a watch component in its rest position after a shock or acceleration suffered by the timepiece.

Claims (14)

1. Bearing (1) for a timepiece comprising a bearing body (2) provided with a through opening (8), said opening (8) comprising a compact assembly (10) under stress comprising: – a first elastic member (3) mounted in a first orifice (9a) of the through opening (8); – a second elastic member (6) arranged between the first elastic member (3) and a second orifice (9b) of said opening (8); – a pivot element (5) provided for pivoting an axis of a watch component, said element (5) being arranged in a central zone of the second elastic member (6) while being positioned opposite the second orifice (9b) through which said axis of said component is capable of being introduced into said opening (8), and – a counter-pivot element (4) interposed between the first and second elastic members (3, 6) which is provided for receiving an end portion of said axis of the component, said counter-pivot element (4) consisting of a central portion (13a) and a peripheral portion (13b), the central portion (13a) comprising a cavity (15) in which a portion of the pivot element (5) is capable of being arranged and said peripheral portion (13b) comprising a contact zone (23) configured to bear on an entire periphery of a flat upper face of the second elastic member (6). 2. Bearing (1) according to the preceding claim, in which the central part (13a) and the peripheral part (13b) respectively form a top (13a) and a base (13b) of the counter-pivot element (4). 3. Bearing (1) according to any one of the preceding claims, in which the counter-pivot element (4) is mounted axially movable in the through opening (8) relative to an axis of revolution (A3) of this opening (8). 4. Bearing (1) according to any one of the preceding claims, in which the central portion (13a) of the counter-pivot element (4) is configured to be inserted into the second orifice (9b) of the through opening (8) during an impact likely to be suffered by the timepiece. 5. Bearing (1) according to any one of the preceding claims, in which the peripheral portion (13b) of the counter-pivot element (4) comprises a stop zone configured to cooperate with the first elastic member (3) during an impact likely to be suffered by the timepiece. 6. Bearing (1) according to any one of the preceding claims, in which the part of the pivot element (5) arranged in the cavity (15) projects from the central zone of the second elastic member (6), this part comprising an external surface which is positioned in the vicinity of a bottom (16) of the cavity (15). 7. Bearing (1) according to any one of the preceding claims, in which the first elastic member (3) is configured to deform essentially axially relative to an axis of revolution (A3) of the through opening (8). 8. Bearing (1) according to any one of the preceding claims, in which the first elastic member (3) comprises fixing elements (11a) of this member (3) in the through opening (8) and constraint elements (11b) intended to press on the central part (13a) of the counter-pivot element (4) and connecting elements (11c) connecting the constraint elements (11b) and the fixing elements (11a) together. 9. Bearing (1) according to any one of the preceding claims, in which the second elastic member (6) comprises a connecting portion (21a) of this member (6) in the through opening (8) and a fixing portion (21b) of the pivot element (5) in a central zone of this member (6), said connecting and fixing portions (21a, 21b) being connected to each other by at least one elastic element (21c) of this member (6). 10. Bearing (1) according to any one of the preceding claims, in which the second elastic member (6) is fixedly mounted in the bearing body (2). 11. Bearing (1) according to any one of the preceding claims, in which the second elastic member (6) is configured to deform essentially radially relative to an axis of revolution (A3) of the through opening (8). 12. Bearing (1) according to any one of the preceding claims, in which the bearing body (2), the through opening (8), the first and second elastic members (3, 6), the counter-pivot element (5) and the pivot element have axes of revolution (A2, A3, A4, A5, A6, A7) which coincide with a central axis (A1) of the bearing (1). 13. Watch movement provided with such a bearing (1) according to any one of the preceding claims. 14. Timepiece comprising a watch movement according to the preceding claim.