EP2410387A1 - Balance wheel with inertia adjustment without insert - Google Patents

Abstract

The balance (1) is in a single component with complementary and coupling portions (42,41) of a resilient arm (40). The coupling portion cooperates with complementary coupling portion in various coupling positions to form a closed loop. A hub (2) pivots about a felloe (5) connected to hub by a joining piece (6), and a balance staff (3) whose inertia is varied based on coupling positions. The hub is made of a micro-machinable material, or silicon, or quartz, or alloy from microelectrochemical systems technology or obtained by lithography, electroplating and molding process.

Description

Field of the invention

The invention relates to a balance for a timepiece, with inertia adjustment to adjust its inertia and / or its balance or / and its oscillation frequency, comprising a hub arranged to cooperate with a shaft pivoting about an axis. a pendulum perpendicular to a balance plane, and a continuous or discontinuous peripheral serge, connected to said hub by at least one joining surface.

The invention further relates to a sprung balance incorporating such a balance.

The invention also relates to a timepiece incorporating such a sprung balance or such a balance.

The invention relates to the field of regulating organs for timepieces, and particularly the balance or the balance spring.

Background of the invention

The accuracy of the calibres depends on the quality of their regulating organ, and the obtaining of very high oscillation frequencies, for example of 10 Hz, to be compared to the usual frequencies of 2.5 to 4 Hz, can only be obtained with the design of suitable regulating members, particularly with regard to the pendulum.

Indeed, the energy to be provided, in the form of elastic torque of the spiral, for the maintenance of the oscillation is proportional to the product, on the one hand of the inertia of the balance around its axis of rotation, by the square of the frequency on the other hand. Thus, for example, at equal energy, the passage of a frequency from 4 Hz to 10 Hz results in about the division by 6 of the inertia. For a frequency of 4 Hz, a pendulum inertia of 12 mg.cm ² is considered good, such a balance typically having a diameter of 9 to 10 mm. Thus, a balance for use at 10 Hz must have a low value inertia, especially less than 2 mg.cm ² .

A rocker for use at 10 Hz must still, for optimal operation, be of minimum mass, especially less than 30 mg, so as to reduce friction in the bearings, so as to avoid disturbances of isochronism in different positions of use.

While being of mass and low inertia, the balance of a high frequency oscillator must, still, allow the adjustment of unbalance and a perfect balancing, static as dynamic, and its construction must authorize operations of adjustment and / or adjustment. It is therefore not possible to use conventional technologies, or even lightened balance solutions such as spokes with spoke serge as described by the patent FR 1275357 in the name of Straumann, or by the patent FR 1 301 938 on behalf of LIP. Indeed, their mass, even reduced, prohibits to obtain as low inertia as desired. Similarly, a titanium beam according to the patent EP 1 562 087 in the name of WATCHES BREGUET SA, designed with a serge and titanium arms and reduced sections, remains of mass and inertia that are greater than what is desired for optimal operation.

It is also sought a quality factor of the order of 500, so significantly higher than those of traditional oscillators where it is close to 220 to 280 for good quality watches. Such a quality factor can only be obtained by the combination of a spiral silicon or the like and a balance fulfilling the above conditions. Obtaining a high quality factor, combined with adjustment and adjustment possibilities, must, again, allow the elimination of the raquetterie.

In addition, the mass of the assembly being limited, the number of components as small as possible is preferred.

However, micro-machinable materials, such as silicon, quartz, which are in principle made in finite dimensions, with very precise tolerances, as part of their production process, are not easily machinable a posteriori.

It is therefore necessary, for regulating members made of such materials or incorporating at least one component in such a material, to have adjustment possibilities in frequency, and / or inertia, avoiding machining, and giving priority to the adjustment possibilities.

Summary of the invention

The inventive step consisted in creating the conditions of a balance structure, including the hub, the serge, and the connections between these two components, as light as possible, moving as far as possible from the hub of the masses of density if possible higher than that of this structure, and to incorporate in this structure adjustment means for making adjustments and adjustments by avoiding rework machining.

For this purpose the invention relates to a balance for a timepiece, with inertia adjustment to adjust its inertia and / or its balance or / and its oscillation frequency, comprising a hub arranged to cooperate with a pivoting shaft around a pendulum axis perpendicular to a balance plane, and a continuous or discontinuous peripheral serge, connected to said hub by at least one joining surface, characterized in that said serge is made integrally with said joining surface and said hub. in a micro-machinable material, or silicon, or quartz, or one of their compounds, or an alloy derived from MEMS technology, or an alloy as obtained by the "LIGA" process, and in that said serge comprises at least a first resilient arm comprising hooking means arranged to cooperate, in different attachment positions, with complementary attachment means that includes said serge to form, in the attachment position, a closed loop of which inertia with respect to said balance shaft is variable according to said attachment positions.

The invention also comprises a balance spring incorporating at least one such balance.

The invention also relates to a timepiece incorporating at least one such sprung balance or at least one such balance.

The preferred use of silicon makes it possible to obtain a beam structure that is both very light and very rigid, which can be dimpled in the junction zone between the hub and the serge. The postponement periphery of inserts, which can be equipped with screws, is favorable to obtaining a properly sized inertia despite the very low total mass of the pendulum. The adjustment and balancing functions are ensured and facilitated.

Such a balance is perfectly suitable for good operation at the frequency of 10 Hz, and at frequencies above 10 Hz.

Brief description of the drawings

• la figure 1 représente, de façon schématisée, et en section perpendiculaire à l'axe de balancier et parallèle au plan de balancier, une première variante de balancier selon l'invention ;
• la figure 2 représente, de façon schématisée, et en section perpendiculaire à l'axe de balancier et parallèle au plan de balancier, une deuxième variante de l'invention ;
• la figure 3 représente, de façon partielle, schématisée, et en section perpendiculaire à l'axe de balancier et parallèle au plan de balancier, une troisième variante de l'invention,
• la figure 4 représente, de façon partielle, schématisée, et en section perpendiculaire à l'axe de balancier et parallèle au plan de balancier, une quatrième variante de l'invention.

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

• the figure 1 represents, schematically, and in section perpendicular to the axis of balance and parallel to the balance plane, a first embodiment of the balance according to the invention;
• the figure 2 represents, schematically, and in section perpendicular to the balance shaft and parallel to the balance plane, a second variant of the invention;
• the figure 3 represents, partially, schematically, and in section perpendicular to the balance shaft and parallel to the balance plane, a third variant of the invention,
• the figure 4 represents, partially, schematically, and in section perpendicular to the balance shaft and parallel to the balance plane, a fourth variant of the invention.

Detailed Description of the Preferred Embodiments

The invention relates to the field of regulating organs for timepieces, and particularly the balance or the balance spring.

The invention is particularly directed to the production of pendulums for high oscillation frequencies, 10 Hz or more.

Non-limiting embodiments are shown in the figures.

The invention relates to the production of a rocker 1 for timepiece with inertia adjustment to adjust its inertia and / or its balance or / and its frequency of oscillation.

This rocker 1 comprises a hub 2 arranged to cooperate with a pivoting shaft about a balance shaft 3 perpendicular to a balance plane 4, and a peripheral serge 5 continuous or discontinuous. This serge 5 can indeed be discontinuous in the context of a search for relief. A serge 5 continues, as visible on the figure 3 , offers the advantage of good rigidity and good aerodynamics, and limits localized flexion by preventing any warping of the balance 1.

This serge 5 is connected to the hub 2 by at least one junction surface 6, which may be constituted by a continuous surface such as a perforated disc or not, or by one or more arms 20. The preparation of a junction surface 6 openwork , in particular with cutouts, crossing or not, between longitudinal members ensuring a good triangulation, makes it possible to further reduce the weight of the balance.

In a preferred manner according to the invention, in all the variants of all the embodiments described below, to obtain a balance with good performances, at an oscillation frequency of 10 Hz or more, the serge 5 is produced. integrally with the junction surface 6 and the hub 2 in a micro-machinable material, or silicon, or quartz, or one of their compounds, or an alloy derived from the MEMS technology, or an alloy as obtained by the LIGA process.

The choice of silicon gives particularly good results and is the preferred solution.

According to the invention, the serge 5 comprises at least one first elastic arm 40. This elastic arm 40 comprises attachment means 41, which are arranged to cooperate, in different attachment positions, with complementary attachment means 42 that comprises the serge 5, to constitute, in the attachment position, a closed loop whose inertia relative to the balance shaft 3 is variable depending on these attachment positions.

The attachment means 41 and the complementary attachment means 42 can be made with all types of complementary profiles with each other, and having a periodic pitch, so as to allow the hooking of each with respect to the other in a plurality of different positions.

It is understood that the deformation of the geometry of the serge 5 induces a variation of inertia of the balance 1.

An important advantage of the invention is that this variation of inertia is reproducible, and very easily memorized, insofar as the attachment means 41 and the complementary attachment means 42 occupy discrete positions, which can very easily be memorized to recreate a particular setting.

Preferably, the periphery of the serge 5 comprises, as visible on the Figures 1 and 2 , Several such elastic arms 40. Their peripheral arrangement, substantially tangential to the serge 5, allows them to assign a significant length, which results in a consequent deviation, for a minimal angle of deformation.

In a preferred embodiment, as visible on the Figures 1 to 3 , the first elastic arm 40 comprises at least at one end 44 an elastic connection with the serge 5. This elastic connection can be achieved by the presence of a slot 60 in the serge, as on the figures 1 and 3 , or more simply, as on the figure 2 , by a reduced section of the serge 5, using the elastic properties of the material of the serge 5, in particular silicon. The first elastic arm 40 preferably has a second end 45 opposite the first end 44, the attachment means 41.

This embodiment of the first elastic arm 40 is not exclusive, as visible on the figure 4 , where such an elastic arm 40 is movable by deformation between two slots 60 and 60A that includes the serge 5. In this fourth variant the elastic arm 40 carries a first projection 61 carrying attachment means 41, which cooperate in different positions hooking, with additional hooking means 42 of the serge 5. It still carries a second protruding 61 A carrying hooking means 41 A, which cooperate, in different hooking positions, with hooking means Supplementary item 42A of serge 5.

In a preferred embodiment, as visible on the Figures 1 to 3 these complementary attachment means 42 are arranged on a second elastic arm 43 that comprises the serge 5. In one embodiment preferred, as visible on Figures 1 to 3 , the second elastic arm 43 comprises at least at a first end 46 an elastic connection with the serge 5. This elastic connection can be achieved by the presence of a slot 62 in the serge, as on the figures 1 and 3 , or more simply, as on the figure 2 , by a reduced section of the serge 5, using the elastic properties of the material of the serge 5, in particular silicon. The second elastic arm 43 preferably comprises at a second end 47 opposite the first end 46, the complementary attachment means 42.

In a particular embodiment, as visible on the figure 3 this second elastic arm 43 further comprises at a third end 48, distant from the first end 46 and the second end 47, at least one elastic connection with the serge 5.

Preferably, in this third variant of the figure 3 , the second elastic arm 43 further comprises at a fourth end, 49 distant from the first end 46 and the second end 47, at least one elastic connection with the serge 5. The second elastic arm 43 further comprises at a fifth end 50 distant the first end 46 and the second end 47 at least one elastic connection with the serge 5. The second resilient arm 43 further comprises at a sixth end 51 other complementary attachment means 52 arranged to cooperate with means of attachment 41 A that comprises another first elastic arm 40A, different from that with which cooperate the complementary attachment means 42.

In short, in this third variant of the figure 3 , a suspended mass 63 is produced, which is movable inside the serge 5, in this particular and non-limiting case between four elastic lips. The attachment means 41 and the complementary fastening means 42 are enclosed in the serge 5. This suspended mass 63 carries the complementary fastening means 42 and the complementary fastening means 52, which respectively cooperate the means attachment 41 of an elastic arm 40, and with the attachment means 41 A of another first elastic arm 40A. This embodiment provides a simple adjustment, like a push button integrated in the serge 5. This solution is also particularly rigid.

The fourth variant of the figure 4 , described above, represents a neighboring version of complete integration in the serge 5 of the attachment means 41 and complementary attachment means 42, but without mobility of the latter.

In one embodiment, as visible on the figures 1 , 3 and 4 , the attachment means 41 and the complementary attachment means 42 are movable relative to each other in a radial direction relative to the balance shaft 3. The radial mobility of these attachment means one against the other results in a radial offset of the center of inertia of the serge portion 5 which incorporates them.

In another embodiment, as visible on the figure 2 , the attachment means 41 and the complementary attachment means 42 are movable relative to each other in a direction tangential to the serge 5. Two different attachment positions are shown on this figure 2 one in full line, the other in broken lines. We can clearly see the difference in shape, and therefore inertia, of the loop formed by the connection of the first elastic arm 40 with the second elastic arm 43. The tangential mobility of these two elastic arms relative to each other is translated by a radial offset of the center of inertia of these two arms. The adoption of a symmetrical execution of the arms, with respect to the balance shaft 3, makes it possible, by performing the same inertia adjustments symmetrically with respect to this axis, to modify the total inertia of the balance 1 without modifying its main axis of inertia, which must be confused with the balance shaft 3. Of course, a differential adjustment remains possible, but is only relevant if additional masses are reported on this balance 1.

Preferably, as visible on the Figures 1 to 4 , the attachment means 41 and the complementary attachment means 42 are constituted by antagonistic tooth sectors.

In a preferred embodiment, these toothed sectors each have teeth that are inclined so as to remain intermeshed with each other in the absence of a disengagement action.

Naturally, the attachment means 41 and the complementary attachment means 42 can be made with all types of complementary profiles with each other, and having a periodic pitch, so as to allow the hooking of some compared to others in a plurality of different positions. For example, these profiles may still consist of notches or the like.

As presented in these different variants, the invention offers the possibility of using a rocker 1 monoblock without any insert, which reduces the number of components. An adapted dimensioning of the serge 5 makes it possible to obtain sufficient inertia. In the case of need of still greater inertia, it is still possible, without departing from the invention, to fix permanently, non-releasably, peripherally of the serge 5, in specific positions, additional masses of known inertia, preferably imposed, of heavy metals or gold or the like. For example, such additional masses may be fixed, in the form of a rivet or the like, at the level of the suspended mass 63 of the figure 3 or zones with a large section of the serge 5, for example at the junction with the junction surface 6 or with the arms 20.

The geometry of the complex appearance of the different variations of rockers presented above is only possible by the realization of these rockers made of micro-machinable materials or preferably silicon, because the processes used allow very easily the realization of such contours, with very high dimensional accuracy, and the possibility of making elastic blades, and therefore to use the elastic properties of the material, in particular silicon.

The invention thus makes it possible to constitute a rocker 1 able to oscillate at high frequency, in particular greater than or equal to 10 Hz, and to allow adjustment or fine-tuning operations, which are moreover reversible and reproducible.

The invention also relates to a sprung balance incorporating at least one such rocker 1, according to any one of the embodiments and any of the variants presented above.

The invention also relates to a timepiece incorporating at least one such sprung balance, or at least one such rocker 1.

The use of silicon allows dimensioning in diameter substantially greater than one would, at similar inertia, with a balance of traditional invoice. The good elasticity of the silicon is particularly advantageous for producing the elastic arms of the invention.

The choice of silicon, in particular, allows the realization, in the serge, elastic holding means, in particular in the form of elastic lip. Similarly, pawl stop means may be combined with such blades or springs made in the silicon serge.

This choice of silicon or an alloy resulting from the MEMS technology, or alloy as obtained by the "LIGA" process, allows, by the excellent resolution during the shaping, to ensure a very precise geometry of the serge 5, and thus avoid all games generating vibrations and damaging to the proper functioning of the oscillator.

The choice of silicon allows moreover to insert the pendulum engravings, decorations, and perform a surface structuring.

The adjustment and adjustment possibilities specific to this new balance according to the invention allow the elimination of any raquetery.

The design of the monobloc balance according to the invention allows a very precise adjustment of the oscillation frequency of the sprung balance in which it is integrated. The adjustment and adjustment of the balance are very precise, and allow the balance to be used in a high frequency oscillator, 10 Hz or more.

The aims which the invention intended to attain are thus perfectly attained.

Claims (15)

Pendulum (1) for a timepiece, with inertia adjustment for adjusting its inertia and / or its balance or / and its frequency of oscillation, comprising a hub (2) arranged to cooperate with a pivoting shaft around a balance beam (3) perpendicular to a balance plane (4), and a continuous or discontinuous peripheral serge (5), connected to said hub (2) by at least one joining surface (6), characterized in that said serge (5) is integrally formed with said junction surface (6) and said hub (2) in a micro-machinable material, or silicon, or quartz, or one of their compounds, or an alloy derived from the MEMS technology , or an alloy as obtained by the "LIGA" method, and in that said serge (5) comprises at least one first elastic arm (40) comprising hooking means (41) arranged to cooperate, in different positions hooking, with complementary fastening means (42) that includes said serge (5) to form, in the attachment position, a closed loop whose inertia with respect to said balance shaft (3) is variable according to said attachment positions. Pendulum (1) according to the preceding claim, characterized in that said first elastic arm (40) comprises at least at one end (44) an elastic connection with said serge (5), and at a second end (45) opposite to said first end (44), said hooking means (41). Pendulum (1) according to one of the preceding claims, characterized in that said complementary attachment means (42) are arranged on a second elastic arm (43) that includes said serge (5). Pendulum (1) according to the preceding claim, characterized in that said second elastic arm (43) comprises at least one first end (46) an elastic connection with said serge (5), and at a second end (47) opposite said first end (46), said complementary attachment means (42). Pendulum (1) according to the preceding claim, characterized in that said second elastic arm (43) further comprises at a third end (48) remote from said first end (46) and said second end (47) at least one elastic connection with said serge (5). Pendulum (1) according to one of claims 4 or 5, characterized in that said second elastic arm (43) further comprises at a fourth end (49) remote from said first end (46) and said second end (47) at least one elastic connection with said serge (5). Pendulum (1) according to one of claims 4 to 6, characterized in that said second elastic arm (43) further comprises at a fifth end (50) remote from said first end (46) and said second end (47) at least one elastic connection with said serge (5). Pendulum (1) according to the preceding claim, characterized in that said second elastic arm (43) further comprises at a sixth end (51) other complementary attachment means (52) arranged to cooperate with hooking means ( 41 A) that comprises another first elastic arm (40A) different from that with which cooperate with said complementary attachment means (42). Balance (1) according to one of the preceding claims, characterized in that said attachment means (41) and said complementary attachment means (42) are movable relative to each other in a radial direction by report to said pendulum axis (3). Balance (1) according to one of the preceding claims, characterized in that said attachment means (41) and said means additional hooking (42) are movable relative to each other in a direction tangential to said serge (5). Pendulum (1) according to one of the preceding claims, characterized in that said attachment means (41) and said complementary attachment means (42) are enclosed in said serge (5). Balance (1) according to one of the preceding claims, characterized in that said attachment means (41) and said complementary attachment means (42) are constituted by antagonistic tooth sectors. Pendulum (1) according to the preceding claim, characterized in that said toothed sectors each comprise a toothing inclined so as to remain meshed with each other in the absence of a disengagement action. Spiral balance incorporating at least one balance (1) according to one of claims 1 to 13. Timepiece incorporating at least one sprung balance according to the preceding claim, or at least one balance (1) according to one of claims 1 to 13.

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