Patent Application
20240411271
Embodiments of the present invention relate to a bearing for a timepiece, in particular a shock-absorbing bearing, for a staff of a timepiece component. The invention further relates to a horological movement provided with such a bearing. The invention further relates to a timepiece comprising such a bearing and/or such a timepiece movement.
In timepieces, the staffs of timepiece components typically have pivots at their ends which rotate in bearings mounted in blanks, such as the plate, or in the bridges of horological movements. For some timepiece components, in particular balances, it is common practice to fit the bearings with a shock-absorbing mechanism. This is because as the staff pivots of these balances are typically 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.
In the prior art, a conventional shock-absorbing bearing commonly comprises a bush such as a drilled jewel provided with a through-hole forming an axial and radial guiding element for the pivot. Such a jewel is driven into a bearing support, commonly referred to as a setting, on which an endstone is mounted, forming an axial stop for the pivot. This setting is intended to transform a radial shock into an axial shock. Such a setting is held against the back of a bearing housing by resilient means, typically a damping spring, arranged to exert an axial stress on the upper part of the endstone. This staff pivot is inserted into the through-hole in the drilled jewel. Such a bearing absorbs shocks, as the assembly formed by the setting, the drilled jewel and the endstone can move thanks to the damping spring.
However, one of the major drawbacks of such a bearing is its lack of robustness, due in particular to the ageing of the lubricant it contains or to wear over time, which alters its operation and makes it less reliable. As a result, such a bearing can no longer guarantee perfect radial recentring of the balance staff in the event of a shock, as this recentring is often random. The problem here lies in the fact that the movement's rate is set at a given moment T, in a given shock-resistant configuration. Following a shock, the configuration of the bearing changes due to imperfect recentring, for example, and the rate adjustment previously carried out is then no longer optimal. In other words, the position of the balance staff has a direct impact on the rate of the movement, and this recentring error must thus be overcome in order to improve chronometric stability.
One of the aims of the invention is to provide a bearing for a timepiece, which bearing has small dimensions and allows the staff of a timepiece component to be repositioned extremely efficiently at all times.
Another aim of the invention is to provide a bearing for repeatedly positioning the staff of a timepiece component.
Another aim of the invention is to provide a bearing of small dimensions.
To this end, the invention relates to a bearing for a timepiece comprising a bearing housing provided with a through-opening, said opening comprising a stressed, compact assembly including:
In other embodiments:
Another aspect of the invention relates to a horological movement fitted with such a bearing.
Another aspect of the invention relates to a timepiece comprising such a horological movement.
Other features and advantages of the invention will become clearer on reading the following description of a particular embodiment of the invention, given merely as an illustrative and non-limiting example, and of the accompanying drawings, among which:
This bearing 1, also referred to as a “horological bearing”, “shock-resistant bearing” or “shock-absorbing bearing”, is particularly suitable for pivoting a ceramic or glass staff, in particular a staff pivot. Such a staff, also referred to as a “rotary staff” or “pivoting staff” or “arbor”, can be a staff of a timepiece component, also referred to as a “staff of a rotary, mobile part”, such as a balance pivot shank when the horological mechanism is an oscillator.
Such a bearing 1 is effectively configured to guide the staff of the timepiece component rotatably about the central axis A1 of the bearing 1, otherwise referred to as the axis A1 of the mounted bearing, and also to stop this staff translationally, in particular to limit its axial and/or radial translation relative to the axis A1.
It should be noted that guiding the staff of this timepiece component also comprises guiding the component itself, which then sees its axial and/or radial translations relative to the axis A1 limited by this bearing 1.
Such a bearing 1 is intended to be assembled or rigidly connected to a blank of the horological movement such as a bridge, for example a balance bridge, or a plate. Alternatively, this bearing 1 can be formed directly in the body of a plate or a bridge, for example by machining.
With reference to
This bearing housing 2 comprises a through-opening 8, also referred to as a “central through-opening”, extending in a direction parallel to that of an axis of revolution A2 of this bearing housing 2, also referred to as the axis of the unit. Such a through-opening 8 comprises first and second orifices 9a, 9b at each of its ends. It should be noted that the first orifice 9a has a cross-section which is preferably larger than the cross-section of the second orifice 9b. As we shall see later, the first orifice 9a is configured to help mount the first resilient member 3 in the through-opening 8 and the second orifice 9b is configured to allow the staff of the timepiece component to be inserted into this same opening 8.
In this bearing housing 2, the through-opening 8 comprises an axis of revolution A3, also referred to as the axis of the opening 8, which is coincident with the central axis A1 of the bearing 1. Such a through-opening 8 has a geometry of revolution about this axis A3 which forms a bed or an enclosure for this bearing housing 2. It should be noted that this bed corresponds to the volume defined in the bearing housing 2 by an inner peripheral wall 20 of the through-opening 8 visible in
In this bearing 1, the through-opening 8 is configured to receive or to participate in the arrangement, or mounting, of the compact assembly 10 in the bearing housing 2. In this configuration, the compact assembly 10 comprises mounting zones 11a, 21a, 22a, 22b intended to cooperate with the inner peripheral wall 20 of the through-opening 8 in order to ensure the arrangement of this compact assembly 10 in the bearing housing 2. Such mounting zones 11a, 21a, 22a, 22b are included in/on the first and second resilient members 3, 6 of this assembly 10. In one alternative embodiment, these mounting zones 11a, 21a, 22a, 22b are included exclusively in/on the first and second resilient members 3, 6. In other words, these mounting zones 11a, 21a, 22a, 22b are the only parts of this compact assembly 10 which carry out/ensure its mounting in the bearing housing 2 to form the bearing 1. As will be seen later, these mounting zones 11a, 21a, 22a, 22b cooperate with this bearing housing 2 by bearing against and/or being fastened to this housing 2.
In this assembly, the pivot element 5, the endstone element 4, the first resilient member 3 and the second resilient member 6 respectively comprise central axes A4, A5, A6, A7. These axes referenced A4, A5, A6, A7 are coincident with the axes A1, A2, A3 respectively of the bearing 1, of the bearing housing 2 and of the through-opening 8 when the compact assembly 10 is mounted in the bearing housing 2.
As already mentioned, this compact assembly 10 is formed by the following succession of components: the first resilient member 3, the endstone element 4, the second resilient member 6 comprising the pivot element 5.
The first resilient member 3, which is for example a resilient element of the return spring type, is intended to resiliently return and adequately axially replace the endstone element 4 and thus the staff of the timepiece component within the opening 8 of the bearing housing 2 following a substantially axial shock suffered by the timepiece, in particular suffered by the horological movement of this timepiece. In other words, the first resilient 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 always axially reposition the staff of the timepiece component in the same place, being constructed in such a way as to absorb substantially axial shocks. It is thus understood that this member 3 is configured to place the staff of the timepiece component axially relative to the axis of revolution referenced A3, in its initial or rest position in response to these shocks.
Such a first resilient member 3 is rigidly connected or fastened to the bearing housing 2. More specifically, this first resilient member 3 is mounted in the first orifice 9a of the through-opening 8. For this purpose, this first resilient member 3 comprises at least one connecting element 11c, at least one stressing element 11b and at least one fastening element 11a which are connected together.
More specifically, this member 3 comprises fastening elements 11a, also referred to as “rigid connection elements”, which are configured so as to be arranged in notches 12 formed in the first orifice 9a of the opening 8. With reference to
The first resilient member 3 further comprises stressing elements 11b which are in contact with the endstone element 4. More specifically, the stressing elements 11b are intended to bear against a central part 13a of the endstone element 4, in particular on a tip 13a of this endstone element 4. These stressing elements 11b are configured to apply to this endstone element 4 an essentially axial return force, in particular an axial and resilient force. With reference to
The first resilient member 3 further comprises connecting elements 11c connecting the stressing elements 11b and the fastening elements 11a together. In this first resilient member 3, there are two of these connecting elements 11c, as can be seen in
In this compact assembly 10, the endstone element 4 is intended to receive an end part (or an end) of the staff of the timepiece component corresponding to the end of the pivot, or to constitute an abutment for the end part of this staff. In the through-opening 8, the endstone element 4 is interposed between the first and second resilient members 3, 6. Such an endstone element 4 is mounted so as to be axially and radially movable in such a through-opening 8 relative to the axis of revolution A3 of this opening 8.
This endstone element 4 consists of the central part 13a and of a peripheral part 13b as well as of inner and outer faces 14a, 14b. It should be noted that in this element 4, the central part 13a is surrounded by the peripheral part 13b. Such an endstone element 4 comprises a step zone 13c which connects the central and peripheral parts 13a, 13b together and which is visible on the outer surface 14b of this element 4 illustrated in
In the inner face 14a of this endstone element 4, the central part 13a comprises a cavity 15, visible in
As mentioned previously, the central part 13a and the peripheral part 13b respectively form the tip 13a and the base 13b of this endstone element 4. This tip 13a is configured/shaped to be inserted into the first resilient member 3, in particular into a space defined therein, which space is delimited by the connecting elements 11c of this first resilient member 3, in particular during a substantially axial shock to which the timepiece may be subjected. This base 13b is configured to form a stop zone for the endstone element 4 by cooperating with the first resilient member 3 during such a shock. In fact, such a stop zone is defined on a part of the outer face 14b of the endstone element 4 located on this base 13b. In this configuration, this stop zone is able to cooperate with the connecting elements 11c and the fastening elements 11a in order to limit the axial displacement of the staff of the timepiece component during a shock, in particular a substantially axial and strong shock.
Such an endstone element 4 can be, for example, an endstone made of a synthetic precious stone or a material that is not mono- or polycrystalline, such as ruby or zirconia, an element made of a metallic material or a silicon-based material (such as mono- or polycrystalline silicon, its oxide, nitride or carbide, which can also be mono- or polycrystalline).
In this compact assembly 10, the pivot element 5 is intended to pivot the staff of the timepiece component. This pivot element 5 comprises a central hole 17 for receiving this staff of the timepiece component and in particular the end part of this staff. This pivot element 5 is arranged in a central zone of the second resilient member 6, being positioned facing the second orifice 9b through which the staff of the timepiece component is capable of being inserted into said through-opening 8. Such a pivot element 5 comprises an upper surface 18a, a lateral surface 18b and a lower surface 18c, with the lateral surface 18b connecting these upper and lower surfaces 18a, 18c together. In this configuration, the upper surface 18a of this element 5 is arranged facing the inner face 14a of the endstone element 4 and the lower surface 18c facing the second orifice 9b. More specifically, this pivot element comprises a part protruding from the second resilient member 6 which is arranged in the cavity 15 of the endstone element 4 with the upper surface 18a which is positioned in the vicinity of a back 16 of this cavity 15.
Such a pivot element 5, also referred to as a “bush”, can be a drilled jewel, typically made of a synthetic precious stone or of a material that is not mono- or polycrystalline, such as ruby or zirconia, or of a silicon-based material (such as mono- or polycrystalline silicon, its oxide, nitride or carbide, which can also be mono- or polycrystalline), or a ring made of metal.
In this compact assembly 10, the second resilient member 6 is fixedly arranged/mounted in the through-opening 8 and thus in the bearing housing 2. In this through-opening 8, this second resilient member 6 is arranged on a shoulder 19 included on the inner peripheral wall 20 of this opening 8. It should be noted that this shoulder 19 is located at the back of the orifice 9a and is orthogonal to the surface of the inner peripheral wall 20.
In this assembly 10, the second resilient 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 always radially recentre the staff of the timepiece component in the same place by being constructed in such a way as to absorb radial shocks.
More specifically, this second resilient member 6 comprises a part 21a for connection to the inner peripheral wall 20 of the through-opening 8, and a part 21b for fastening the pivot element 5 in the central zone of this member 6, said connecting and fastening parts 21a, 21b being connected to each other by at least one resilient element 21c of this second resilient member 6. It should be noted that the connecting and fastening parts 21a, 21b are rigid parts of this member 6 in comparison with the resilient element 21c. These connecting and fastening parts 21a, 21b are liable to deform elastically when subjected to stress.
Said at least one resilient element 21c is configured to ensure the radial deformation of the second resilient member 6 by controlling the displacement of the fastening part 21b relative to the connecting part 21a during shocks to the movement. In other words, the resilient element 21c is configured to place the connecting part 21a or the pivot element 5 or the staff of the timepiece component radially relative to the axis of revolution referenced A3, in its initial or rest position in response to shocks.
This second resilient member 6 also has flat top and bottom faces which are preferably substantially parallel to each other.
The connecting part 21a forms an outer peripheral wall of this second resilient member 6. In this configuration, when the second resilient member 6 is mounted in the through-opening 8, a lateral surface 22a of this peripheral wall, and thus of this connecting part 21a, rests on all or part of the inner peripheral wall 20 of this opening 8. More specifically, this connecting part 21a is configured to deform elastically when the second resilient member 6 is inserted into the through-opening 8. This connecting part 21a is then able to bear against the inner peripheral wall 20 of the opening 8 from its lateral surface 22a. By way of example, the second resilient member 6 can be inserted into this through-opening 8 by driving in.
This connecting part 21a further comprises a contact surface 22b which is configured to cooperate with the shoulder 19 included in the through-opening 8. With reference to the aforementioned example, it should be noted that the second resilient member 6 is inserted by driving into the through-opening 8 until it comes into abutment against the shoulder 19 of the through-opening 8 via the contact surface 22b of the connecting part 21a. It should be noted that this contact surface 22b is included on the flat lower face of this second member 6.
It is thus understood that such a connecting part 21a allows the second resilient member 6 to be fixedly arranged/mounted in the through-opening 8. In other words, this connecting part 21a helps to ensure that the second resilient member 6 is fastened or held in place with sufficient strength to prevent any axial, radial and/or angular relative displacement of this second member 6 relative to the axis of revolution A3 of the opening 8.
It should be noted that this connecting part 21a forms part of the mounting zones 11a, 21a, 22a, 22b of the compact assembly 10 in the bearing housing 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.
The connecting part 21a further comprises a support surface 22c forming/including the perimeter of the flat upper face which is configured to cooperate with the contact zone 23 of the endstone element 4. In fact, the base 13b of the endstone element 4 is able to bear directly on this support surface 22c. In the connecting part 21a, this support surface 22c is positioned above or vertical to the contact surface 22b. Moreover, this support surface 22c is substantially parallel to the contact surface 22b.
As already mentioned, the second resilient member 6 further comprises a part 21b for fastening the pivot element 5 in the central zone of this second member 6. This attachment part 21b forms an inner peripheral wall of this second resilient member 6. The pivot element 5 can be a part attached to this second member 6 with its lateral surface 18b which is configured to be wholly or partly connected to this inner peripheral wall. Such a connection can be made by driving in, bonding or welding.
It should be noted that in one alternative embodiment, this pivot element 5 can be an integral part of this second member 6 by being made in one piece with the fastening part 21b. In this configuration, the central zone of this second member 6 is then considered as being/forming this pivot element 5.
This second resilient member 6 can be produced by micro-fabrication, using a deep reactive ion etching process (usually referred to by its acronym “DRIE”) for a member 6 comprising, in particular, silicon, or using a Liga process such as UV-Liga for a member 6 based, for example, on nickel.
Thus such a bearing 1 according to the invention has small/reduced overall dimensions compared with bearings of the prior art, without any consequence on the operation of this bearing 1. This reduced size is achieved in particular by the compact assembly 10 formed by the first and second resilient members 3, 6 and the endstone element 4 and pivot element 5, and more precisely by:
It should be noted that in this bearing 1, the endstone element 4, by bearing on the upper face of the second resilient member 6, exerts only an axial and resilient force on the entire periphery of the flat upper face of this second resilient member 6 under the action of the stressing elements 11b bearing on the tip 13a of the endstone element 4. This force is then applied by the contact zone 23 of the endstone element 4 to the support surface 22c forming said periphery, vertical to the shoulder 19 of the through-opening 8.
It should also be noted that a substantially axial shock is to be understood as being a shock that is “strictly axial” or “essentially axial” or “partly axial”. Similarly, a substantially radial shock is to be understood to be a shock that is “strictly radial” or “essentially radial” or “partly radial”.
Moreover, in this description, “substantially parallel” is understood to mean “strictly parallel or essentially parallel”.
Such a bearing 1 thus helps to ensure axial and radial recentring/repositioning of the staff of a timepiece component in its rest position after the timepiece has been subjected to a shock or acceleration.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23177607.1 | Jun 2023 | EP | regional |
