EP3796102B1 - Method for manufacturing a balance for a timepiece - Google Patents

Method for manufacturing a balance for a timepiece Download PDF

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Publication number
EP3796102B1
EP3796102B1 EP20201790.1A EP20201790A EP3796102B1 EP 3796102 B1 EP3796102 B1 EP 3796102B1 EP 20201790 A EP20201790 A EP 20201790A EP 3796102 B1 EP3796102 B1 EP 3796102B1
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EP
European Patent Office
Prior art keywords
metal alloy
ppm
hub
felloe
process according
Prior art date
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Application number
EP20201790.1A
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German (de)
French (fr)
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EP3796102A1 (en
Inventor
Alexandre Haemmerli
Jean-Claude Martin
Lionel Paratte
Yves Winkler
Gianni Di Domenico
Pascal Winkler
Jean-Luc Helfer
Lionel TOMBEZ
Baptiste Hinaux
Donald Corson
Michel Willemin
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Swatch Group Research and Development SA
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Swatch Group Research and Development SA
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Priority to EP20201790.1A priority Critical patent/EP3796102B1/en
Publication of EP3796102A1 publication Critical patent/EP3796102A1/en
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Publication of EP3796102B1 publication Critical patent/EP3796102B1/en
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00—Mechanisms for stabilising frequency
    • G04B17/04—Oscillators acting by spring tension
    • G04B17/06—Oscillators with hairsprings, e.g. balance
    • G04B17/063—Balance construction
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00—Mechanisms for stabilising frequency
    • G04B17/04—Oscillators acting by spring tension
    • G04B17/06—Oscillators with hairsprings, e.g. balance
    • G04B17/066—Manufacture of the spiral spring
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00—Mechanisms for stabilising frequency
    • G04B17/20—Compensation of mechanisms for stabilising frequency
    • G04B17/22—Compensation of mechanisms for stabilising frequency for the effect of variations of temperature
    • G04B17/222—Compensation of mechanisms for stabilising frequency for the effect of variations of temperature with balances
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00—Mechanisms for stabilising frequency
    • G04B17/20—Compensation of mechanisms for stabilising frequency
    • G04B17/22—Compensation of mechanisms for stabilising frequency for the effect of variations of temperature
    • G04B17/227—Compensation of mechanisms for stabilising frequency for the effect of variations of temperature composition and manufacture of the material used
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B18/00—Mechanisms for setting frequency
    • G04B18/006—Mechanisms for setting frequency by adjusting the devices fixed on the balance
    • G—PHYSICS
    • G04—HOROLOGY
    • G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
    • G04D3/00—Watchmakers' or watch-repairers' machines or tools for working materials
    • G04D3/0002—Watchmakers' or watch-repairers' machines or tools for working materials for mechanical working other than with a lathe
    • G04D3/0035—Watchmakers' or watch-repairers' machines or tools for working materials for mechanical working other than with a lathe for components of the regulating mechanism
    • G04D3/0038—Watchmakers' or watch-repairers' machines or tools for working materials for mechanical working other than with a lathe for components of the regulating mechanism for balances
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D25/00—Special casting characterised by the nature of the product
    • B22D25/02—Special casting characterised by the nature of the product by its peculiarity of shape; of works of art
    • B22D25/026—Casting jewelry articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/04—Influencing the temperature of the metal, e.g. by heating or cooling the mould
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C16/00—Alloys based on zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
    • G04C3/04—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance

Definitions

  • the invention relates to a method of manufacturing a balance wheel for a timepiece comprising a rim, a hub and at least one arm connecting the hub to said rim.
  • the oscillator or resonator of a mechanical watch consists of a spiral spring and a flywheel called a balance wheel.
  • the thermal variations vary the rigidity of the hairspring, as well as the geometries of the hairspring and the balance wheel, which modifies the spring constant and the inertia, and therefore the frequency of oscillation.
  • Watchmakers have worked hard to have stable temperature oscillators and several avenues have been explored/exploited, one of which earned Charles-Edouard Council a Nobel Prize for the development of the Elinvar alloy whose modulus of elasticity increases with temperature and compensates for the increase in inertia of the balance wheel.
  • quartz hairspring provides thermal compensation for the change in inertia of the balance wheel.
  • quartz is limited to materials having a thermal expansion coefficient of the order of 10 ppm/°C, which corresponds for example titanium and platinum.
  • the main problem with these materials is machinability and mastery of a fine structure and/or a perfect finish (mirror polish, for example).
  • titanium its relatively low density limits its use for large balances and in the case of platinum its high price limits its use to prestige and luxury products.
  • the object of the present invention is to remedy these drawbacks by proposing a method of manufacturing a balance made of new materials allowing simpler and more precise manufacture, so as to reduce, for example, the dispersion of inertia and/or unbalance within the same production batch.
  • a metal alloy balance wheel can be made using a simplified manufacturing process such as a casting process or a hot forming process. Furthermore, the metal alloy in its at least partially amorphous form has the property of having a much greater elastic range than its crystalline counterpart, thanks to the absence of dislocation. This property makes it possible to overmold or integrate into the balance wheel elements making it possible to improve the centering as well as to adjust the inertia and/or the unbalance.
  • a pendulum 1 for a timepiece comprises in a traditional manner a rim 2, continuous or not, defining the outer diameter of the balance 1, a hub 4, forming its central part and provided with a hole 6 intended to receive a shaft (not shown) defining the pivot axis of the balance 1.
  • the hub 4 is solidly connected to the rim 2 by arms 8.
  • the arms 8 are here four in number and are arranged at 90°.
  • pendulums with two or three arms, arranged respectively at 180° or 120°.
  • the rim 2, the hub 4 and the arms 8 are made from the same metal alloy.
  • the balance 1 is monobloc, that is to say made in one piece.
  • the balance 1 can for example be made entirely of an alloy based on platinum or palladium which will be described in detail below. Platinum in particular having a high density (21000 kg/m 3 ), the platinum alloy used in the invention also has a high density (15.5 g/cm 3 ), so that the addition of elements in dense material to increase the inertia of the pendulum will not necessarily be necessary.
  • the cooling step d) can be done at a cooling rate chosen to obtain a crystalline, partially amorphous or totally amorphous alloy.
  • the balance 1 can also be made entirely, for example, of an alloy based on titanium or zirconium which will be described in detail below.
  • Zirconium for example, having a lower density
  • the zirconium alloy used in the invention also has a lower density (6.5 g/cm 3 ), so that the addition of elements made of denser material for increasing the inertia of the balance wheel is recommended, especially if you want to make a small balance wheel for small movements. These elements make it possible to increase the inertia of the balance wheel while maintaining an aesthetic serge geometry and with good aerodynamic properties.
  • the rim 2 may comprise first molded inertia adjustment elements 10, said first inertia adjustment elements 10 being made of a material having a density greater than the density of the metal alloy.
  • These first adjustment elements of the inertia 10 can for example be made of tungsten or tungsten carbide, and are obtained by molding.
  • the method according to the invention comprises a step of overmolding said first inertia adjustment elements 10 in the rim 2, by means of inserts placed in the mold before the introduction of the metal alloy, and molded, said first inertia adjustment elements 10 being made of a first material having a density greater than the density of said metal alloy.
  • the arms and the hub of the balance are made of a metal alloy, the rim being made of a material having a density greater than the density of said metal alloy used for the arms and the hub.
  • This material may itself be the metal alloy based on platinum or palladium as defined below or another material.
  • the arms and the hub of the balance wheel are made of the amorphous zirconium-based metal alloy as defined below to enable the balance wheel to be paired with a hairspring preferably in monocrystalline quartz, and the serge is made in another material having a higher density than the density of the zirconium-based metal alloy used for the arms and the hub in order to improve the inertia of the balance wheel.
  • the cooling step d) can be done at a cooling rate chosen to obtain a crystalline, partially amorphous or totally amorphous alloy.
  • the methods of the invention according to the first or second embodiments advantageously use the properties of a metal alloy capable of being in an at least partially amorphous form when it is heated to easily shape it in order to produce a metal alloy balance.
  • a metal alloy capable of being in an at least partially amorphous form when it is heated allows great ease in shaping allowing the manufacture of parts with complicated shapes with greater precision.
  • a method advantageously used is the hot forming of an amorphous preform.
  • This preform is obtained by melting in a furnace the metallic elements intended to constitute the metallic alloy. This fusion is carried out under a controlled atmosphere with the aim of obtaining as low a contamination of the alloy as possible with oxygen. Once these elements have been melted, they are cast as a semi-finished product, then cooled rapidly in order to maintain the partially or totally amorphous state.
  • hot forming is carried out in order to obtain a final part. This hot forming is carried out by pressing in a temperature range comprised between the glass transition temperature Tg and the crystallization temperature Tx of the metal alloy for a determined time to maintain an at least partially amorphous structure. This is done in order to retain the characteristic elastic properties of amorphous metals.
  • the balance can also be made by casting or by injection.
  • This process consists of casting or injecting the metal alloy heated to a temperature between its glass transition temperature and its crystallization temperature to be at least partially amorphous in a mold having the shape of the final part.
  • the mold can be reused or dissolved to release the parts.
  • the molding process has the advantage of perfectly replicating the geometry of the balance wheel, including any decorations or surface structuring. Less dispersion of inertia and better centering on an Iot of production of pendulums are obtained.
  • the molding process makes it possible to obtain a balance wheel with aesthetic geometry, with sharp interior angles, a serge and/or curved arm profile, and a perfect finish. It is also possible to provide a non-continuous serge.
  • the mold will be made in silicon by a DRIE process. It is obvious that the mold can also be produced by machining by milling, laser, spark erosion or any other type of machining.
  • the characteristic elastic properties of amorphous metals are used to overmold or integrate functional and/or decorative elements in the serge and/or at the level of the arms and/or at the level of the hub, for example by means of corresponding inserts placed in the front mold introducing the metal alloy heated between its glass transition temperature and its crystallization temperature to be at least partially amorphous.
  • the rim 2 can comprise housings 12 intended to receive second inertia and/or unbalance adjustment elements 14, 15 as represented on the picture 3 .
  • These housings 12 can advantageously be provided during the manufacture of the balance 1 by molding, in accordance with the methods of the invention.
  • the second inertia and/or unbalance adjustment elements 14, 15 may for example be weights, split weights, pins 14, split pins, or pins with unbalance 15, which act as weights. These elements are driven or clipped into the corresponding housings 12.
  • a pin 14 is shown inserted in its housing 12, as well as a pin with an unbalance 15 inserted in its housing 12.
  • figure 4 shows a sectional view along line AA of the picture 3 representing the pin with unbalance 15 inserted in the housing 12 provided in the serge 2.
  • these elements for increasing the inertia of the balance are preferably used with a rim made of a low density material, such as titanium or zirconium, but can also be used with a rim in another material.
  • the slots 12 shown in the picture 3 can also constitute housings intended to receive aesthetic and/or luminescent elements, such as tritium tubes (not shown), or capsules of phosphorescent materials (of the Superluminova type, for example) or fluorescent materials.
  • aesthetic and/or luminescent elements such as tritium tubes (not shown), or capsules of phosphorescent materials (of the Superluminova type, for example) or fluorescent materials.
  • one or the other of the methods comprises a step of overmolding flexible centering elements 16, 17 on the hub 4, on its inner periphery or on its surface.
  • the hub 4 can comprise integrated flexible centering elements, which allow self-centering of the balance when it is mounted on an axle thanks to the elastic deformation of said flexible centering elements.
  • said integrated flexible centering elements 16 are elastic blades provided on the inner periphery of hub 4 so as to be positioned in hole 6.
  • said integrated flexible centering elements 17 are provided on the surface of the hub 4 and are distributed around the hole 6.
  • the flexible centering elements 16 and 17 can advantageously be put in place during the manufacture of the balance beam 1 by molding, in accordance with the methods of the invention.
  • one or the other of the methods comprises a step of overmolding third flexible inertia adjustment elements 19, 20, 22a, 22b in the arm 8.
  • at least the one of the arms 8 carries integrated third flexible inertia adjustment elements.
  • the end of the arm 8 on the side of the rim 2 ends in two branches 8a, 8b forming between them a housing 18 in which is integrated a third element for adjusting the inertia 19 flexible bistable in "V" for the adjustment of the frequency.
  • the third inertia adjustment element 20 flexible in buckling for the adjustment of the frequency.
  • the third inertia adjustment element 20 is made of a material having different expansion properties from the metal alloy of the balance of the invention, such as silicon or silicon oxide.
  • the end of the arm 8 on the side of the serge 2 ends in three branches 8a, 8b, 8c forming between them two housings 18a, 18b in which are integrated third inertia adjustment elements 22a, 22b flexible multi- stable ratchet for frequency adjustment.
  • These third flexible inertia adjusting elements 19, 20, 22a, 22b for adjusting the frequency can advantageously be put in place during the manufacture of the balance 1 by molding, in accordance with the methods of the invention.
  • These third flexible inertia adjusting elements 19, 20, 22a, 22b for adjusting the frequency can be used both when the whole of the balance wheel is in the same metal alloy and when the arms are in metal alloy, the rest of the balance, and in particular the serge, being in another material.
  • one of the arm 8, of the rim 2 and of the hub 4 has a structured surface state. Only one of the elements can have a structured surface condition or all the elements of the balance wheel can have a structured surface condition, this structured surface condition may be the same or different.
  • the figure 10 represents a balance wheel of the invention for which the serge 2 has a structured surface state different from the structured surface state presented by the arm 8. This structured surface state can be a polished, satin-brushed, sandblasted, beaded, sunburst state , etc.
  • the mold for manufacturing the balance wheel microstructures forming a photonic network in order to replicate these microstructures on the surface of the balance wheel.
  • These microstructures can make it possible to create a photonic crystal giving the part a certain color, a hologram, or a diffraction grating which can constitute an anti-counterfeiting element.
  • the structures are introduced directly into the mould, and are replicated during manufacture of the balance wheels by hot forming, which no longer requires finishing operations. It is also possible to add a logo to the mould.
  • the metal alloy used in the methods of the invention exhibits a coefficient of thermal expansion typically less than 25 ppm/°C and greater than 7 ppm/°C, and is capable of being in an at least partially amorphous form when it is heated to a temperature between its glass transition temperature and its crystallization temperature.
  • the metal alloy used in the methods of the invention is based on an element chosen from the group consisting of platinum, zirconium, titanium, palladium, nickel, aluminum and iron.
  • the expression “based on an element” means that said metal alloy contains at least 50% by weight of said element.
  • Said metal alloy used in the present invention may be platinum-based and has a coefficient of thermal expansion of less than 12 ppm/°C, preferably between 8 ppm/°C and 12 ppm/°C.
  • the metal alloy used in the present invention can also be based on zirconium and has a coefficient of thermal expansion of less than 12 ppm/°C, preferably between 8 ppm/°C and 11 ppm/°C.
  • the metal alloy used in the present invention can also be based on palladium and has a coefficient of thermal expansion of less than 20 ppm/°C, preferably between 13 ppm/°C and 18 ppm/°C.
  • the alloys used in the invention do not contain any impurities. However, they may include traces of impurities which may result, often inevitably, from the production of said alloys.
  • the alloys used in the present invention When the alloys used in the present invention have a coefficient of thermal expansion of less than 12 ppm/°C and greater than 8 ppm/°C, they can be used to produce at least part of a balance which will be paired with a hairspring. preferably monocrystalline quartz.
  • the alloys used in the present invention having a coefficient of thermal expansion of less than 20 ppm/°C and greater than 13 ppm/°C can be used to produce at least part of a balance which will be paired with a metal hairspring or in silicon.
  • said metal alloy used in the present invention based on platinum consists, in values in atomic %, of: 57.5% Pt, 14.7% Cu, 5.3% Ni, 22.5% P.
  • Such an alloy has a coefficient of expansion temperature between 11 and 12 ppm/°C.
  • said zirconium-based metal alloy used in the present invention consists, in values in atomic %, of: 58.5% Zr, 15.6% Cu, 12.8% Ni, 10.3% Al, 2.8% Nb.
  • Such an alloy has a thermal expansion coefficient of between 10.5 and 11 ppm/°C.
  • said palladium-based metal alloy used in the present invention consists, in values in atomic %, of: 43% Pd, 27% Cu, 10% Ni, 20% P.
  • Such an alloy has a coefficient of expansion temperature between 15 and 16 ppm/°C.
  • the balance wheel according to the invention is made of a material allowing the use of a simple manufacturing process while having a coefficient of thermal expansion allowing it to be paired with a balance spring in monocrystalline quartz, and/or in metal or in silicon. , preferably monocrystalline quartz.
  • the balance wheel according to the invention also makes it possible to have at least arms having a coefficient of thermal expansion allowing it to be paired with a monocrystalline quartz hairspring, and/or metal or silicon, while having a high inertia while keeping a compact and aesthetic serge geometry, of small volume, using a suitable serge, either comprising elements made of a material of greater density, or being itself made of a higher density material.

Description

Domaine de l'inventionField of the invention

L'invention concerne un procédé de fabrication d'un balancier pour pièce d'horlogerie comprenant une serge, un moyeu et au moins un bras reliant le moyeu à ladite serge.The invention relates to a method of manufacturing a balance wheel for a timepiece comprising a rim, a hub and at least one arm connecting the hub to said rim.

Arrière-plan de l'inventionBackground of the invention

L'oscillateur ou résonateur d'une montre mécanique est constitué d'un ressort spiral et d'un volant d'inertie appelé balancier. Les variations thermiques font varier la rigidité du spiral, ainsi que les géométries du spiral et du balancier, ce qui modifie la constante de ressort et l'inertie, et donc la fréquence d'oscillation. Les horlogers ont beaucoup travaillé pour avoir des oscillateurs stables en température et plusieurs voies ont été explorées/exploitées dont une qui a valu un Prix Nobel à Charles-Edouard Guillaume pour le développement de l'alliage Elinvar dont le module d'élasticité augmente avec la température et compense l'augmentation d'inertie du balancier. Par la suite, le développement du silicium oxydé, donc compensé thermiquement, a surpassé les performances de l'Elinvar et a pour avantage d'être moins sensible aux champs magnétiques. De même le spiral en quartz monocristallin permet une compensation thermique du changement d'inertie du balancier. Mais contrairement au silicium oxydé dont l'épaisseur d'oxyde peut être variée suivant le matériau de balancier utilisé, le quartz est limité aux matériaux ayant un coefficient de dilatation thermique de l'ordre de 10 ppm/°C, ce qui correspond par exemple au titane et au platine. Le problème principal de ces matériaux est l'usinabilité et la maîtrise de structure fine et/ou d'une finition parfaite (poli miroir par exemple). Dans le cas du titane, sa relativement faible densité limite son utilisation pour des grands balanciers et dans le cas du platine son prix élevé limite son utilisation à des produits de prestige et de luxe.The oscillator or resonator of a mechanical watch consists of a spiral spring and a flywheel called a balance wheel. The thermal variations vary the rigidity of the hairspring, as well as the geometries of the hairspring and the balance wheel, which modifies the spring constant and the inertia, and therefore the frequency of oscillation. Watchmakers have worked hard to have stable temperature oscillators and several avenues have been explored/exploited, one of which earned Charles-Edouard Guillaume a Nobel Prize for the development of the Elinvar alloy whose modulus of elasticity increases with temperature and compensates for the increase in inertia of the balance wheel. Subsequently, the development of oxidized silicon, therefore thermally compensated, surpassed the performance of the Elinvar and has the advantage of being less sensitive to magnetic fields. Similarly, the monocrystalline quartz hairspring provides thermal compensation for the change in inertia of the balance wheel. But unlike oxidized silicon whose oxide thickness can be varied according to the balance material used, quartz is limited to materials having a thermal expansion coefficient of the order of 10 ppm/°C, which corresponds for example titanium and platinum. The main problem with these materials is machinability and mastery of a fine structure and/or a perfect finish (mirror polish, for example). In the case of titanium, its relatively low density limits its use for large balances and in the case of platinum its high price limits its use to prestige and luxury products.

On connaît des procédés de fabrication de balancier par moulage d'un matériau partiellement amorphe, comme dans le document EP 3 170 579 A1 .Processes for manufacturing balances by molding a partially amorphous material are known, as in the document EP 3 170 579 A1 .

Résumé de l'inventionSummary of the invention

La présente invention a pour but de remédier à ces inconvénients en proposant un procédé de fabrication d'un balancier réalisé dans de nouveaux matériaux permettant une fabrication plus simple et plus précise, de manière à réduire par exemple la dispersion d'inertie et/ou de balourd au sein d'un même lot de production.The object of the present invention is to remedy these drawbacks by proposing a method of manufacturing a balance made of new materials allowing simpler and more precise manufacture, so as to reduce, for example, the dispersion of inertia and/or unbalance within the same production batch.

A cet effet, l'invention se rapporte tout d'abord à un procédé de fabrication d'un balancier pour pièce d'horlogerie comprenant une serge, un moyeu et au moins un bras reliant le moyeu à ladite serge, la serge, le moyeu et les bras étant réalisés dans un alliage métallique, ledit procédé comprenant les étapes suivantes:

  1. a) réaliser un moule ayant la forme négative du balancier
  2. b) se munir d'un alliage métallique présentant un coefficient de dilatation thermique inférieur à 25 ppm/°C et capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation
  3. c) introduire dans le moule l'alliage métallique, ledit alliage métallique étant chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation pour être formé à chaud et former un balancier
  4. d) refroidir ledit alliage métallique pour obtenir un balancier dans ledit alliage métallique
  5. e) libérer le balancier obtenu à l'étape d) de son moule, le procédé étant caractérisé en ce qu'il comprend une étape de surmoulage d'éléments de centrage flexibles sur le moyeu.
To this end, the invention relates first of all to a method of manufacturing a balance wheel for a timepiece comprising a rim, a hub and at least one arm connecting the hub to said rim, the rim, the hub and the arms being made of a metal alloy, said method comprising the following steps:
  1. a) make a mold having the negative shape of the pendulum
  2. b) provide a metal alloy having a thermal expansion coefficient of less than 25 ppm/°C and capable of being in an at least partially amorphous form when heated to a temperature between its glass transition temperature and its crystallization temperature
  3. c) introducing the metal alloy into the mould, said metal alloy being heated to a temperature between its glass transition temperature and its crystallization temperature to be hot-formed and form a pendulum
  4. d) cooling said metal alloy to obtain a pendulum in said metal alloy
  5. e) releasing the balance wheel obtained in step d) from its mould, the method being characterized in that it comprises a step of overmolding flexible centering elements on the hub.

La présente invention concerne également un procédé de fabrication d'un balancier pour pièce d'horlogerie comprenant une serge, un moyeu et au moins un bras reliant le moyeu à ladite serge, le moyeu et le bras étant réalisés dans un alliage métallique, et la serge étant réalisée dans un matériau présentant une masse volumique supérieure à la masse volumique dudit alliage métallique dans lequel le moyeu et le bras sont réalisés, ledit procédé comprenant les étapes suivantes :

  • a) réaliser un moule ayant la forme négative du balancier ;
  • a') insérer dans le moule une serge ou des éléments de serge réalisés dans un matériau présentant une masse volumique supérieure à la masse volumique dudit alliage métallique ;
  • b) se munir d'un alliage métallique présentant un coefficient de dilatation thermique inférieur à 25 ppm/°C et capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation ;
  • c) introduire dans le moule l'alliage métallique, ledit alliage métallique étant chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation pour être formé à chaud et surmouler la serge ou les éléments de serge pour former un balancier avec inserts ;
  • d) refroidir ledit alliage métallique pour obtenir un balancier avec inserts ;
  • e) libérer le balancier obtenu à l'étape d) de son moule,
le procédé étant caractérisé en ce qu'il comprend une étape de surmoulage d'éléments de centrage flexibles sur le moyeu.The present invention also relates to a method of manufacturing a pendulum for a timepiece comprising a rim, a hub and at least one arm connecting the hub to said rim, the hub and the arm being made of a metal alloy, and the serge being made of a material having a density greater than the density of said metal alloy in which the hub and the arm are made, said method comprising the following steps:
  • a) making a mold having the negative shape of the pendulum;
  • a′) inserting into the mold a serge or serge elements made of a material having a density greater than the density of said metal alloy;
  • b) provide a metal alloy having a thermal expansion coefficient of less than 25 ppm/°C and capable of being in an at least partially amorphous form when heated to a temperature between its glass transition temperature and its crystallization temperature;
  • c) introducing the metal alloy into the mould, said metal alloy being heated to a temperature between its glass transition temperature and its crystallization temperature to be hot-formed and overmolding the serge or the serge elements to form a pendulum with inserts;
  • d) cooling said metal alloy to obtain a balance wheel with inserts;
  • e) releasing the pendulum obtained in step d) from its mould,
the method being characterized in that it comprises a step of overmolding flexible centering elements on the hub.

Grâce aux propriétés des métaux amorphes, un balancier en alliage métallique peut être réalisé en utilisant un procédé de fabrication simplifié tel qu'un procédé de coulée ou un procédé de formage à chaud. En outre, l'alliage métallique sous sa forme au moins partiellement amorphe a pour propriété d'avoir une plage élastique bien plus grande que son équivalent cristallin, grâce à l'absence de dislocation. Cette propriété permet de surmouler ou d'intégrer au balancier des éléments permettant d'améliorer le centrage ainsi que de régler l'inertie et/ou le balourd.Thanks to the properties of amorphous metals, a metal alloy balance wheel can be made using a simplified manufacturing process such as a casting process or a hot forming process. Furthermore, the metal alloy in its at least partially amorphous form has the property of having a much greater elastic range than its crystalline counterpart, thanks to the absence of dislocation. This property makes it possible to overmold or integrate into the balance wheel elements making it possible to improve the centering as well as to adjust the inertia and/or the unbalance.

Description sommaire des dessinsBrief description of the drawings

D'autres particularités et avantages ressortiront clairement de la description qui en est faite ci-après, à titre indicatif et nullement limitatif, en référence aux dessins annexés, dans lesquels :

  • la figure 1 est une vue en perspective d'un balancier fabriqué selon l'invention ;
  • la figure 2 est une vue de dessus partielle d'une variante de balancier réalisé selon l'invention ;
  • la figure 3 est une vue de dessus partielle d'une autre variante de balancier réalisé selon l'invention ;
  • la figure 4 est une vue en coupe selon l'axe A-A de la figure 3 ; et
  • les figures 5 à 10 sont des vues de dessus partielles d'autres variantes de balancier réalisé selon l'invention.
Other features and advantages will emerge clearly from the description given below, by way of indication and in no way limiting, with reference to the appended drawings, in which:
  • the figure 1 is a perspective view of a balance made according to the invention;
  • the figure 2 is a partial top view of a variant of a balance made according to the invention;
  • the picture 3 is a partial top view of another variant of a balance made according to the invention;
  • the figure 4 is a sectional view along the axis AA of the picture 3 ; and
  • the figures 5 to 10 are partial top views of other variants of balance produced according to the invention.

Description détaillée des modes de réalisation préférésDetailed Description of Preferred Embodiments

En référence à la figure 1, il est représenté un balancier 1 pour pièce d'horlogerie. Un tel balancier 1 comprend d'une manière traditionnelle une serge 2, continue ou non, définissant le diamètre extérieur du balancier 1, un moyeu 4, formant sa partie centrale et muni d'un trou 6 destiné à recevoir un arbre (non représenté) définissant l'axe de pivotement du balancier 1. Le moyeu 4 est relié solidairement à la serge 2 par des bras 8. Les bras 8 sont ici au nombre de quatre et sont disposés à 90°. On trouve aussi usuellement des balanciers avec deux ou trois bras, disposés respectivement à 180° ou 120°.With reference to the figure 1 , there is shown a pendulum 1 for a timepiece. Such a balance 1 comprises in a traditional manner a rim 2, continuous or not, defining the outer diameter of the balance 1, a hub 4, forming its central part and provided with a hole 6 intended to receive a shaft (not shown) defining the pivot axis of the balance 1. The hub 4 is solidly connected to the rim 2 by arms 8. The arms 8 are here four in number and are arranged at 90°. There are also usually pendulums with two or three arms, arranged respectively at 180° or 120°.

Selon un premier mode de réalisation, la serge 2, le moyeu 4 et les bras 8 sont réalisés dans un même alliage métallique. D'une manière avantageuse, le balancier 1 est monobloc, c'est-à-dire réalisé d'une seule pièce.According to a first embodiment, the rim 2, the hub 4 and the arms 8 are made from the same metal alloy. Advantageously, the balance 1 is monobloc, that is to say made in one piece.

Le balancier 1 peut par exemple être réalisé entièrement dans un alliage à base de platine ou de palladium qui sera décrit en détail ci-après. Le platine notamment présentant une grande masse volumique (21000 kg/m3), l'alliage en platine utilisé dans l'invention présente également une masse volumique élevée (15.5 g/cm3), de sorte que l'ajout d'éléments en matériau dense pour augmenter l'inertie du balancier ne sera pas forcément nécessaire.The balance 1 can for example be made entirely of an alloy based on platinum or palladium which will be described in detail below. Platinum in particular having a high density (21000 kg/m 3 ), the platinum alloy used in the invention also has a high density (15.5 g/cm 3 ), so that the addition of elements in dense material to increase the inertia of the pendulum will not necessarily be necessary.

A cet effet, conformément à un premier mode de réalisation de l'invention, le procédé de fabrication d'un balancier 1, dans lequel la serge 2, le moyeu 4 et le bras 8 sont réalisés dans un même alliage métallique, comprend les étapes suivantes:

  1. a) réaliser un moule ayant la forme négative du balancier 1, y compris d'éventuelles structures décoratives de surface ;
  2. b) se munir d'un alliage métallique présentant un coefficient de dilatation thermique typiquement inférieur à 25 ppm/°C et capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation ;
  3. c) introduire dans le moule l'alliage métallique, ledit alliage métallique étant chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation pour être formé à chaud et former un balancier ;
  4. d) refroidir ledit alliage métallique pour obtenir un balancier 1 dans ledit alliage métallique ;
  5. e) libérer le balancier 1 obtenu à l'étape d) de son moule. Le procédé comprend encore une étape de surmoulage d'éléments de centrage flexibles sur le moyeu.
To this end, in accordance with a first embodiment of the invention, the method of manufacturing a balance wheel 1, in which the rim 2, the hub 4 and the arm 8 are made of the same metal alloy, comprises the steps following:
  1. a) making a mold having the negative shape of the pendulum 1, including any decorative surface structures;
  2. b) use a metal alloy having a coefficient of thermal expansion typically less than 25 ppm/°C and capable of being in an at least partially amorphous form when heated to a temperature between its glass transition temperature and its crystallization temperature;
  3. c) introducing the metal alloy into the mould, said metal alloy being heated to a temperature between its glass transition temperature and its crystallization temperature to be hot-formed and form a pendulum;
  4. d) cooling said metal alloy to obtain a balance wheel 1 in said metal alloy;
  5. e) releasing the pendulum 1 obtained in step d) from its mould. The method further comprises a step of overmolding flexible centering elements on the hub.

L'étape d) de refroidissement peut se faire à une vitesse de refroidissement choisie pour obtenir un alliage cristallin, partiellement amorphe ou totalement amorphe.The cooling step d) can be done at a cooling rate chosen to obtain a crystalline, partially amorphous or totally amorphous alloy.

Le balancier 1 peut également être réalisé entièrement par exemple dans un alliage à base de titane ou de zirconium qui sera décrit en détails ci-après. Le zirconium par exemple présentant une masse volumique plus faible, l'alliage en zirconium utilisé dans l'invention présente également une masse volumique plus faible (6.5 g/cm3), de sorte que l'ajout d'éléments en matériau plus dense pour augmenter l'inertie du balancier est recommandé, notamment si l'on souhaite réaliser un balancier de petite taille pour de petits mouvements. Ces éléments permettent d'augmenter l'inertie du balancier tout en gardant une géométrie de serge esthétique et avec de bonnes propriétés aérodynamiques.The balance 1 can also be made entirely, for example, of an alloy based on titanium or zirconium which will be described in detail below. Zirconium, for example, having a lower density, the zirconium alloy used in the invention also has a lower density (6.5 g/cm 3 ), so that the addition of elements made of denser material for increasing the inertia of the balance wheel is recommended, especially if you want to make a small balance wheel for small movements. These elements make it possible to increase the inertia of the balance wheel while maintaining an aesthetic serge geometry and with good aerodynamic properties.

Ainsi, selon une première variante représentée sur la figure 2, la serge 2 peut comprendre des premiers éléments de réglage de l'inertie 10 surmoulés, lesdits premiers éléments de réglage de l'inertie 10 étant réalisés dans un matériau présentant une masse volumique supérieure à la masse volumique de l'alliage métallique. Ces premiers éléments de réglage de l'inertie 10 peuvent par exemple être en tungstène ou carbure de tungstène, et sont obtenus par surmoulage.Thus, according to a first variant shown in the picture 2 , the rim 2 may comprise first molded inertia adjustment elements 10, said first inertia adjustment elements 10 being made of a material having a density greater than the density of the metal alloy. These first adjustment elements of the inertia 10 can for example be made of tungsten or tungsten carbide, and are obtained by molding.

A cet effet, le procédé selon l'invention comprend une étape de surmoulage desdits premiers éléments de réglage de l'inertie 10 dans la serge 2, au moyen d'inserts placés dans le moule avant l'introduction de l'alliage métallique, et surmoulés, lesdits premiers éléments de réglage de l'inertie 10 étant réalisés dans un premier matériau présentant une masse volumique supérieure à la masse volumique dudit alliage métallique.To this end, the method according to the invention comprises a step of overmolding said first inertia adjustment elements 10 in the rim 2, by means of inserts placed in the mold before the introduction of the metal alloy, and molded, said first inertia adjustment elements 10 being made of a first material having a density greater than the density of said metal alloy.

Selon un second mode de réalisation, les bras et le moyeu du balancier sont réalisés dans un alliage métallique, la serge étant réalisée dans un matériau présentant une masse volumique supérieure à la masse volumique dudit alliage métallique utilisé pour les bras et le moyeu. Ce matériau peut être lui-même l'alliage métallique à base de platine ou de palladium tel que défini ci-dessous ou un autre matériau.According to a second embodiment, the arms and the hub of the balance are made of a metal alloy, the rim being made of a material having a density greater than the density of said metal alloy used for the arms and the hub. This material may itself be the metal alloy based on platinum or palladium as defined below or another material.

Par exemple, les bras et le moyeu du balancier sont réalisés dans l'alliage métallique amorphe à base de zirconium tel que défini ci-dessous pour permettre d'appairer le balancier avec un spiral de préférence en quartz monocristallin, et la serge est réalisée dans un autre matériau présentant une masse volumique supérieure à la masse volumique de l'alliage métallique à base de zirconium utilisé pour les bras et le moyeu afin d'améliorer l'inertie du balancier.For example, the arms and the hub of the balance wheel are made of the amorphous zirconium-based metal alloy as defined below to enable the balance wheel to be paired with a hairspring preferably in monocrystalline quartz, and the serge is made in another material having a higher density than the density of the zirconium-based metal alloy used for the arms and the hub in order to improve the inertia of the balance wheel.

A cet effet, conformément à un second mode de réalisation de l'invention, le procédé de fabrication d'un balancier pour pièce d'horlogerie dans lequel le moyeu 4 et les bras 8 sont réalisés dans un alliage métallique, et la serge 2 est réalisée dans un second matériau présentant une masse volumique supérieure à la masse volumique dudit alliage métallique dans lequel le moyeu 4 et les bras 8 sont réalisés, comprend les étapes suivantes:

  • a) réaliser un moule ayant la forme négative du balancier, y compris d'éventuelles structures décoratives de surface ;
  • a') insérer dans le moule une serge ou des éléments de serge réalisés dans un matériau présentant une masse volumique supérieure à la masse volumique dudit alliage métallique;
  • b) se munir d'un alliage métallique présentant un coefficient de dilatation thermique typiquement inférieur à 25 ppm/°C et capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation ;
  • c) introduire dans le moule l'alliage métallique, ledit alliage métallique étant chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation pour être formé à chaud et surmouler la serge ou les éléments de serge pour former un balancier avec inserts ;
  • d) refroidir ledit alliage métallique pour obtenir un balancier avec ses inserts ;
  • e) libérer le balancier obtenu à l'étape d) de son moule. Le procédé comprend encore une étape de surmoulage d'éléments de centrage flexibles sur le moyeu.
To this end, in accordance with a second embodiment of the invention, the method of manufacturing a balance wheel for a timepiece in which the hub 4 and the arms 8 are made of a metal alloy, and the rim 2 is made of a second material having a density greater than the density of said metal alloy in which the hub 4 and the arms 8 are made, comprises the following steps:
  • a) making a mold having the negative shape of the pendulum, including any decorative surface structures;
  • a') inserting into the mold a serge or serge elements made of a material having a density greater than the density of said metal alloy;
  • b) provide a metal alloy having a coefficient of thermal expansion typically less than 25 ppm/°C and capable of being in an at least partially amorphous form when heated to a temperature between its glass transition temperature and its crystallization temperature;
  • c) introducing the metal alloy into the mould, said metal alloy being heated to a temperature between its glass transition temperature and its crystallization temperature to be hot-formed and overmolding the serge or the serge elements to form a pendulum with inserts;
  • d) cooling said metal alloy to obtain a balance wheel with its inserts;
  • e) releasing the pendulum obtained in step d) from its mould. The method further comprises a step of overmolding flexible centering elements on the hub.

L'étape d) de refroidissement peut se faire à une vitesse de refroidissement choisie pour obtenir un alliage cristallin, partiellement amorphe ou totalement amorphe.The cooling step d) can be done at a cooling rate chosen to obtain a crystalline, partially amorphous or totally amorphous alloy.

Les procédés de l'invention selon le premier ou deuxième modes de réalisation utilisent de manière avantageuse les propriétés d'un alliage métallique capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé pour le mettre facilement en forme afin de réaliser un balancier en alliage métallique.The methods of the invention according to the first or second embodiments advantageously use the properties of a metal alloy capable of being in an at least partially amorphous form when it is heated to easily shape it in order to produce a metal alloy balance.

En effet, un alliage métallique capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé permet une grande facilité dans la mise en forme permettant la fabrication de pièces aux formes compliquées avec une plus grande précision. Cela est dû aux caractéristiques particulières des « métaux amorphes » qui peuvent se ramollir tout en restant amorphes durant un certain temps dans un intervalle de température [Tg - Tx] donné propre à chaque alliage (par exemple pour l'alliage à base de Zr : Tg=440°C et Tx=520°C). Il est ainsi possible de les mettre en forme sous une contrainte relativement faible et à une température peu élevée permettant alors l'utilisation d'un procédé simplifié tel que le formage à chaud. L'utilisation d'un tel matériau permet en outre de reproduire très précisément des géométries fines car la viscosité de l'alliage diminue fortement en fonction de la température dans l'intervalle de température [Tg - Tx] et l'alliage épouse ainsi tous les détails du négatif. Par exemple, pour un matériau à base de platine tel que défini ci-dessous, la mise en forme se fait aux alentours de 300°C pour une viscosité atteignant 103 Pa.s pour une contrainte de 1MPa, au lieu d'une viscosité de 1012 Pa.s à la température Tg. L'utilisation de matrices a pour avantage la création de pièces en trois dimensions de grande précision, ce que le découpage ou l'étampage ne permettent pas d'obtenir.Indeed, a metal alloy capable of being in an at least partially amorphous form when it is heated allows great ease in shaping allowing the manufacture of parts with complicated shapes with greater precision. This is due to particular characteristics of "amorphous metals" which can soften while remaining amorphous for a certain time in a given temperature interval [Tg - Tx] specific to each alloy (for example for the Zr-based alloy: Tg=440° C and Tx=520°C). It is thus possible to shape them under relatively low stress and at a low temperature, then allowing the use of a simplified process such as hot forming. The use of such a material also makes it possible to reproduce very precisely fine geometries because the viscosity of the alloy decreases sharply as a function of the temperature in the temperature interval [Tg - Tx] and the alloy thus marries all the details of the negative. For example, for a platinum-based material as defined below, shaping takes place at around 300°C for a viscosity reaching 10 3 Pa.s for a stress of 1 MPa, instead of a viscosity of 10 12 Pa.s at the temperature Tg. The advantage of using dies is the creation of high-precision three-dimensional parts, which cutting or stamping cannot achieve.

Un procédé utilisé avantageusement est le formage à chaud d'une préforme amorphe. Cette préforme est obtenue par fusion dans un four des éléments métalliques destinés à constituer l'alliage métallique. Cette fusion est faite sous atmosphère contrôlée avec pour but d'obtenir une contamination de l'alliage en oxygène aussi faible que possible. Une fois ces éléments fondus, ils sont coulés sous forme de produit semi-fini, puis refroidis rapidement afin de conserver l'état partiellement ou totalement amorphe. Une fois la préforme réalisée, le formage à chaud est effectué dans le but d'obtenir une pièce définitive. Ce formage à chaud est réalisé par pressage dans une gamme de température comprise entre la température de transition vitreuse Tg et la température de cristallisation Tx de l'alliage métallique durant un temps déterminé pour conserver une structure au moins partiellement amorphe. Ceci est fait dans le but de conserver les propriétés élastiques caractéristiques des métaux amorphes.A method advantageously used is the hot forming of an amorphous preform. This preform is obtained by melting in a furnace the metallic elements intended to constitute the metallic alloy. This fusion is carried out under a controlled atmosphere with the aim of obtaining as low a contamination of the alloy as possible with oxygen. Once these elements have been melted, they are cast as a semi-finished product, then cooled rapidly in order to maintain the partially or totally amorphous state. Once the preform has been produced, hot forming is carried out in order to obtain a final part. This hot forming is carried out by pressing in a temperature range comprised between the glass transition temperature Tg and the crystallization temperature Tx of the metal alloy for a determined time to maintain an at least partially amorphous structure. This is done in order to retain the characteristic elastic properties of amorphous metals.

Typiquement pour l'alliage à base de Zr et pour une température de 440°C, le temps de pressage ne devra pas dépasser 120 secondes environ. Ainsi, le formage à chaud permet de conserver l'état amorphe initial de la préforme. Les différentes étapes de mise en forme définitive du balancier monobloc selon l'invention sont alors :

  1. 1) chauffage des matrices ayant la forme négative du balancier jusqu'à une température choisie
  2. 2) introduction de la préforme en métal amorphe entre les matrices chaudes,
  3. 3) application d'une force de fermeture sur les matrices afin de répliquer la géométrie de ces dernières sur la préforme en métal amorphe,
  4. 4) attente durant un temps maximal choisi,
  5. 5) ouverture des matrices,
  6. 6) refroidissement du balancier, et
  7. 7) sortie du balancier des matrices.
Typically for the Zr-based alloy and for a temperature of 440°C, the pressing time should not exceed approximately 120 seconds. Thus, hot forming makes it possible to preserve the initial amorphous state of the preform. The different stages of final shaping of the one-piece balance wheel according to the invention are then:
  1. 1) heating of the dies having the negative shape of the pendulum up to a chosen temperature
  2. 2) introduction of the amorphous metal preform between the hot dies,
  3. 3) application of a closing force on the dies in order to replicate the geometry of the latter on the amorphous metal preform,
  4. 4) waiting for a chosen maximum time,
  5. 5) opening of the dies,
  6. 6) pendulum cooling, and
  7. 7) output of the die balancer.

Bien entendu, le balancier peut être aussi réalisé par coulée ou par injection. Ce procédé consiste à couler ou injecter l'alliage métallique chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation pour être au moins partiellement amorphe dans un moule possédant la forme de la pièce définitive.Of course, the balance can also be made by casting or by injection. This process consists of casting or injecting the metal alloy heated to a temperature between its glass transition temperature and its crystallization temperature to be at least partially amorphous in a mold having the shape of the final part.

Le moule peut être réutilisé ou dissout pour libérer les pièces. Le procédé par moulage présente l'avantage de répliquer parfaitement la géométrie du balancier, y compris d'éventuels décors ou structuration de surface. On obtient une moins grande dispersion d'inertie et un meilleur centrage sur un Iot de production de balanciers. Le procédé par moulage permet d'obtenir un balancier à la géométrie esthétique, avec des angles intérieurs vifs, un profil de serge et/ou de bras bombé, et une finition parfaite. Il est également possible de prévoir une serge non continue. Pour une qualité maximale, le moule sera réalisé dans du silicium par un procédé DRIE. Il est bien évident que le moule peut également être réalisé par usinage par fraisage, laser, électroérosion ou tout autre type d'usinage.The mold can be reused or dissolved to release the parts. The molding process has the advantage of perfectly replicating the geometry of the balance wheel, including any decorations or surface structuring. Less dispersion of inertia and better centering on an Iot of production of pendulums are obtained. The molding process makes it possible to obtain a balance wheel with aesthetic geometry, with sharp interior angles, a serge and/or curved arm profile, and a perfect finish. It is also possible to provide a non-continuous serge. For maximum quality, the mold will be made in silicon by a DRIE process. It is obvious that the mold can also be produced by machining by milling, laser, spark erosion or any other type of machining.

Les propriétés élastiques caractéristiques des métaux amorphes sont utilisées pour surmouler ou intégrer des éléments fonctionnels et/ou décoratifs dans la serge et/ou au niveau des bras et/ou au niveau du moyeu par exemple au moyen d'inserts correspondants placés dans le moule avant l'introduction de l'alliage métallique chauffé entre sa température de transition vitreuse et sa température de cristallisation pour être au moins partiellement amorphe.The characteristic elastic properties of amorphous metals are used to overmold or integrate functional and/or decorative elements in the serge and/or at the level of the arms and/or at the level of the hub, for example by means of corresponding inserts placed in the front mold introducing the metal alloy heated between its glass transition temperature and its crystallization temperature to be at least partially amorphous.

Indépendamment du premier ou second modes de réalisation des procédés de l'invention, la serge 2 peut comprendre des logements 12 destinés à recevoir des deuxièmes éléments de réglage de l'inertie et/ou de balourd 14, 15 comme représenté sur la figure 3. Ces logements 12 peuvent avantageusement être prévus lors de la fabrication du balancier 1 par moulage, conformément aux procédés de l'invention. Les deuxièmes éléments de réglage de l'inertie et/ou de balourd 14, 15 peuvent être par exemple des masselottes, des masselottes fendues, des goupilles 14, des goupilles fendues, ou des goupilles avec balourd 15, qui font office de masselottes. Ces éléments sont chassés ou clippés dans les logements correspondants 12. Sur la figure 3 sont représentées une goupille 14 insérée dans son logement 12, ainsi qu'une goupille avec balourd 15 insérée dans son logement 12. La figure 4 montre une vue en coupe selon la ligne A-A de la figure 3 représentant la goupille avec balourd 15 insérée dans le logement 12 prévu dans la serge 2.Independently of the first or second embodiments of the methods of the invention, the rim 2 can comprise housings 12 intended to receive second inertia and/or unbalance adjustment elements 14, 15 as represented on the picture 3 . These housings 12 can advantageously be provided during the manufacture of the balance 1 by molding, in accordance with the methods of the invention. The second inertia and/or unbalance adjustment elements 14, 15 may for example be weights, split weights, pins 14, split pins, or pins with unbalance 15, which act as weights. These elements are driven or clipped into the corresponding housings 12. On the picture 3 a pin 14 is shown inserted in its housing 12, as well as a pin with an unbalance 15 inserted in its housing 12. figure 4 shows a sectional view along line AA of the picture 3 representing the pin with unbalance 15 inserted in the housing 12 provided in the serge 2.

Il est bien évident que ces éléments pour augmenter l'inertie du balancier sont utilisés préférentiellement avec une serge réalisée dans un matériau de faible densité, tel que le titane ou le zirconium mais peuvent être aussi utilisés avec une serge dans un autre matériau.It is obvious that these elements for increasing the inertia of the balance are preferably used with a rim made of a low density material, such as titanium or zirconium, but can also be used with a rim in another material.

Pour augmenter l'inertie du balancier, il est également possible de prévoir une serge plus épaisse ou plus large, notamment dans le cas de balanciers plus grands.To increase the inertia of the balance, it is also possible to provide a thicker or wider rim, in particular in the case of larger balances.

Les logements 12 représentés sur la figure 3 peuvent également constituer des logements destinés à recevoir des éléments esthétiques et/ ou luminescents, tels que des tubes de tritium (non représentés), ou des capsules de matériaux phosphorescents (du type Superluminova, par exemple) ou fluorescents.The slots 12 shown in the picture 3 can also constitute housings intended to receive aesthetic and/or luminescent elements, such as tritium tubes (not shown), or capsules of phosphorescent materials (of the Superluminova type, for example) or fluorescent materials.

Selon l'invention, l'un ou l'autre des procédés comprend une étape de surmoulage d'éléments de centrage flexibles 16, 17 sur le moyeu 4, sur son pourtour intérieur ou à sa surface. Ainsi, le moyeu 4 peut comprendre des éléments de centrage flexibles intégrés, qui permettent un auto-centrage du balancier lors de son montage sur un axe grâce à la déformation élastique desdits éléments de centrage flexibles.According to the invention, one or the other of the methods comprises a step of overmolding flexible centering elements 16, 17 on the hub 4, on its inner periphery or on its surface. Thus, the hub 4 can comprise integrated flexible centering elements, which allow self-centering of the balance when it is mounted on an axle thanks to the elastic deformation of said flexible centering elements.

Selon la figure 5, lesdits éléments de centrage flexibles intégrés 16 sont des lames élastiques prévues sur le pourtour intérieur du moyeu 4 de manière à être positionnées dans le trou 6.According to figure 5 , said integrated flexible centering elements 16 are elastic blades provided on the inner periphery of hub 4 so as to be positioned in hole 6.

Selon la figure 6, lesdits éléments de centrage flexibles intégrés 17 sont prévus sur la surface du moyeu 4 et sont répartis autour du trou 6. Les éléments de centrage flexibles 16 et 17 peuvent avantageusement être mis en place lors de la fabrication du balancier 1 par moulage, conformément aux procédés de l'invention.According to figure 6 , said integrated flexible centering elements 17 are provided on the surface of the hub 4 and are distributed around the hole 6. The flexible centering elements 16 and 17 can advantageously be put in place during the manufacture of the balance beam 1 by molding, in accordance with the methods of the invention.

Selon une autre variante de l'invention, l'un ou l'autre des procédés comprend une étape de surmoulage de troisièmes éléments de réglage de l'inertie 19, 20, 22a, 22b flexibles dans le bras 8. Ainsi, au moins l'un des bras 8 porte des troisièmes éléments de réglage de l'inertie flexibles intégrés.According to another variant of the invention, one or the other of the methods comprises a step of overmolding third flexible inertia adjustment elements 19, 20, 22a, 22b in the arm 8. Thus, at least the one of the arms 8 carries integrated third flexible inertia adjustment elements.

Selon la figure 7, l'extrémité du bras 8 du côté de la serge 2 se termine en deux branches 8a, 8b formant entre elles un logement 18 dans lequel est intégré un troisième élément de réglage de l'inertie 19 flexible bistable en « V » pour le réglage de la fréquence.According to figure 7 , the end of the arm 8 on the side of the rim 2 ends in two branches 8a, 8b forming between them a housing 18 in which is integrated a third element for adjusting the inertia 19 flexible bistable in "V" for the adjustment of the frequency.

Selon la figure 8, il est prévu dans le logement 18 un troisième élément de réglage de l'inertie 20 flexible en flambage pour le réglage de la fréquence. A cet effet, le troisième élément de réglage de l'inertie 20 est réalisé dans un matériau présentant des propriétés de dilatation différentes de l'alliage métallique du balancier de l'invention, tel que le silicium ou l'oxyde de silicium.According to figure 8 , there is provided in the housing 18 a third inertia adjustment element 20 flexible in buckling for the adjustment of the frequency. For this purpose, the third inertia adjustment element 20 is made of a material having different expansion properties from the metal alloy of the balance of the invention, such as silicon or silicon oxide.

Selon la figure 9, l'extrémité du bras 8 du côté de la serge 2 se termine en trois branches 8a, 8b, 8c formant entre elles deux logements 18a, 18b dans lesquels sont intégrés des troisièmes éléments de réglage de l'inertie 22a, 22b flexibles multi-stables à cliquet pour le réglage de la fréquence.According to figure 9 , the end of the arm 8 on the side of the serge 2 ends in three branches 8a, 8b, 8c forming between them two housings 18a, 18b in which are integrated third inertia adjustment elements 22a, 22b flexible multi- stable ratchet for frequency adjustment.

Ces troisièmes éléments de réglage de l'inertie flexibles 19, 20, 22a, 22b pour le réglage de la fréquence peuvent avantageusement être mis en place lors de la fabrication du balancier 1 par moulage, conformément aux procédés de l'invention.These third flexible inertia adjusting elements 19, 20, 22a, 22b for adjusting the frequency can advantageously be put in place during the manufacture of the balance 1 by molding, in accordance with the methods of the invention.

Ces troisièmes éléments de réglage de l'inertie flexibles 19, 20, 22a, 22b pour le réglage de la fréquence peuvent être aussi bien utilisés lorsque l'ensemble du balancier est dans un même alliage métallique que lorsque les bras sont en alliage métallique, le reste du balancier, et notamment la serge, étant dans un autre matériau.These third flexible inertia adjusting elements 19, 20, 22a, 22b for adjusting the frequency can be used both when the whole of the balance wheel is in the same metal alloy and when the arms are in metal alloy, the rest of the balance, and in particular the serge, being in another material.

Selon une autre variante de l'invention, on utilise dans l'un ou l'autre des procédés de l'invention un moule présentant des microstructures formant un décor ou un réseau photonique. Ainsi, l'un du bras 8, de la serge 2 et du moyeu 4 présente un état de surface structuré. Seul l'un des éléments peut présenter un état de surface structuré ou tous les éléments du balancier peuvent présenter un état de surface structuré, cet état de surface structuré pouvant être identique ou différent. La figure 10 représente un balancier de l'invention pour lequel la serge 2 présente un état de surface structuré différent de l'état de surface structuré présenté par le bras 8. Cet état de surface structuré peut être un état poli, satiné, sablé, perlé, ensoleillé, etc. Il est possible de prévoir également dans le moule pour la fabrication du balancier des microstructures formant un réseau photonique afin de répliquer ces microstructures à la surface du balancier. Ces microstructures peuvent permettre de créer un cristal photonique donnant à la pièce une certaine couleur, un hologramme, ou un réseau de diffraction pouvant constituer un élément anti-contrefaçon. Les structures sont directement introduites dans le moule, et sont répliquées lors de la fabrication des balanciers par formage à chaud, ce qui ne nécessite plus d'opérations de terminaison. Il est également possible d'ajouter un logo au moule.According to another variant of the invention, use is made in one or other of the methods of the invention of a mold having microstructures forming a decoration or a photonic network. Thus, one of the arm 8, of the rim 2 and of the hub 4 has a structured surface state. Only one of the elements can have a structured surface condition or all the elements of the balance wheel can have a structured surface condition, this structured surface condition may be the same or different. The figure 10 represents a balance wheel of the invention for which the serge 2 has a structured surface state different from the structured surface state presented by the arm 8. This structured surface state can be a polished, satin-brushed, sandblasted, beaded, sunburst state , etc. It is also possible to provide in the mold for manufacturing the balance wheel microstructures forming a photonic network in order to replicate these microstructures on the surface of the balance wheel. These microstructures can make it possible to create a photonic crystal giving the part a certain color, a hologram, or a diffraction grating which can constitute an anti-counterfeiting element. The structures are introduced directly into the mould, and are replicated during manufacture of the balance wheels by hot forming, which no longer requires finishing operations. It is also possible to add a logo to the mould.

L'alliage métallique utilisé dans les procédés de l'invention présente un coefficient de dilatation thermique typiquement inférieur à 25 ppm/°C et supérieur à 7 ppm/°C, et est capable d'être sous une forme au moins partiellement amorphe lorsqu'il est chauffé à une température comprise entre sa température de transition vitreuse et sa température de cristallisation.The metal alloy used in the methods of the invention exhibits a coefficient of thermal expansion typically less than 25 ppm/°C and greater than 7 ppm/°C, and is capable of being in an at least partially amorphous form when it is heated to a temperature between its glass transition temperature and its crystallization temperature.

De préférence, l'alliage métallique utilisé dans les procédés de l'invention est à base d'un élément choisi parmi le groupe constitué du platine, du zirconium, du titane, du palladium, du nickel, de l'aluminium et du fer.Preferably, the metal alloy used in the methods of the invention is based on an element chosen from the group consisting of platinum, zirconium, titanium, palladium, nickel, aluminum and iron.

Dans la présente description, l'expression « à base d'un élément » signifie que ledit alliage métallique contient au moins 50% en poids dudit élément.In the present description, the expression “based on an element” means that said metal alloy contains at least 50% by weight of said element.

Ledit alliage métallique utilisé dans la présente invention peut être à base de platine et présente un coefficient de dilatation thermique inférieur 12 ppm/°C, de préférence compris entre 8 ppm/°C et 12 ppm/°C.Said metal alloy used in the present invention may be platinum-based and has a coefficient of thermal expansion of less than 12 ppm/°C, preferably between 8 ppm/°C and 12 ppm/°C.

Un tel alliage métallique à base de platine peut être constitué, en valeurs en % atomique, de :

  • une base de platine dont la teneur constitue la balance,
  • 13 à 17% de cuivre,
  • 3 à 7% de nickel,
  • 20 à 25% de phosphore.
Such a platinum-based metal alloy may consist, in values in atomic %, of:
  • a base of platinum whose content constitutes the balance,
  • 13 to 17% copper,
  • 3 to 7% nickel,
  • 20 to 25% phosphorus.

L'alliage métallique utilisé dans la présente invention peut aussi être à base de zirconium et présente un coefficient de dilatation thermique inférieur 12 ppm/°C, de préférence compris entre 8 ppm/°C et 11 ppm/°C.The metal alloy used in the present invention can also be based on zirconium and has a coefficient of thermal expansion of less than 12 ppm/°C, preferably between 8 ppm/°C and 11 ppm/°C.

Un tel alliage métallique à base de zirconium peut être constitué, en valeurs en % atomique, de :

  • une base de zirconium dont la teneur constitue la balance,
  • 14 à 20% de cuivre,
  • 12 à 13% de nickel,
  • 9 à 11% d'aluminium,
  • 2 à 4 % de niobium.
Such a zirconium-based metal alloy may consist, in values in atomic %, of:
  • a zirconium base whose content constitutes the balance,
  • 14 to 20% copper,
  • 12 to 13% nickel,
  • 9 to 11% aluminum,
  • 2 to 4% niobium.

L'alliage métallique utilisé dans la présente invention peut aussi être à base de palladium et présente un coefficient de dilatation thermique inférieur à 20 ppm/°C, de préférence compris entre 13 ppm/°C et 18 ppm/°C.The metal alloy used in the present invention can also be based on palladium and has a coefficient of thermal expansion of less than 20 ppm/°C, preferably between 13 ppm/°C and 18 ppm/°C.

Un tel alliage métallique à base de palladium peut être constitué, en valeurs en % atomique, de :

  • une base de palladium, dont la teneur constitue la balance,
  • 25 à 30% de cuivre,
  • 8 à 12% de nickel,
  • 18 à 22% de phosphore.
Such a palladium-based metal alloy may consist, in values in atomic %, of:
  • a palladium base, the content of which constitutes the balance,
  • 25 to 30% copper,
  • 8 to 12% nickel,
  • 18 to 22% phosphorus.

Idéalement, les alliages utilisés dans l'invention ne contiennent aucune impureté. Toutefois, ils peuvent comprendre des traces d'impuretés qui peuvent résulter, de manière souvent inévitable, de l'élaboration desdits alliages.Ideally, the alloys used in the invention do not contain any impurities. However, they may include traces of impurities which may result, often inevitably, from the production of said alloys.

Lorsque les alliages utilisés dans la présente invention présentent un coefficient de dilatation thermique inférieur à 12 ppm/°C et supérieur à 8 ppm/°C, ils peuvent être utilisés pour réaliser au moins une partie d'un balancier qui sera appairé à un spiral de préférence en quartz monocristallin. Les alliages utilisés dans la présente invention présentant un coefficient de dilatation thermique inférieur à 20 ppm/°C et supérieur à 13 ppm/°C peuvent être utilisés pour réaliser au moins une partie d'un balancier qui sera appairé à un spiral en métal ou en silicium.When the alloys used in the present invention have a coefficient of thermal expansion of less than 12 ppm/°C and greater than 8 ppm/°C, they can be used to produce at least part of a balance which will be paired with a hairspring. preferably monocrystalline quartz. The alloys used in the present invention having a coefficient of thermal expansion of less than 20 ppm/°C and greater than 13 ppm/°C can be used to produce at least part of a balance which will be paired with a metal hairspring or in silicon.

Plus préférentiellement, ledit alliage métallique utilisé dans la présente invention à base de platine est constitué, en valeurs en % atomique, de : 57.5% Pt, 14.7% Cu, 5.3% Ni, 22.5% P. Un tel alliage présente un coefficient de dilatation thermique compris entre 11 et 12 ppm/°C.More preferably, said metal alloy used in the present invention based on platinum consists, in values in atomic %, of: 57.5% Pt, 14.7% Cu, 5.3% Ni, 22.5% P. Such an alloy has a coefficient of expansion temperature between 11 and 12 ppm/°C.

Plus préférentiellement, ledit alliage métallique utilisé dans la présente invention à base de zirconium est constitué, en valeurs en % atomique, de : 58.5% Zr, 15.6% Cu, 12.8% Ni, 10.3% Al, 2.8% Nb. Un tel alliage présente un coefficient de dilatation thermique compris entre 10.5 et 11 ppm/°C.More preferably, said zirconium-based metal alloy used in the present invention consists, in values in atomic %, of: 58.5% Zr, 15.6% Cu, 12.8% Ni, 10.3% Al, 2.8% Nb. Such an alloy has a thermal expansion coefficient of between 10.5 and 11 ppm/°C.

Plus préférentiellement, ledit alliage métallique utilisé dans la présente invention à base de palladium est constitué, en valeurs en % atomique, de : 43% Pd, 27% Cu, 10% Ni, 20% P. Un tel alliage présente un coefficient de dilatation thermique compris entre 15 et 16 ppm/°C.More preferably, said palladium-based metal alloy used in the present invention consists, in values in atomic %, of: 43% Pd, 27% Cu, 10% Ni, 20% P. Such an alloy has a coefficient of expansion temperature between 15 and 16 ppm/°C.

Ainsi, le balancier selon l'invention est réalisé dans un matériau permettant d'utiliser un procédé de fabrication simple tout en présentant un coefficient de dilatation thermique permettant de l'appairer à un spiral en quartz monocristallin, et/ou en métal ou en silicium, de préférence en quartz monocristallin. Le balancier selon l'invention permet également d'avoir au moins des bras présentant un coefficient de dilatation thermique permettant de l'appairer à un spiral en quartz monocristallin, et/ou en métal ou en silicium, tout en ayant une grande inertie en gardant une géométrie de serge compacte et esthétique, de petit volume, à l'aide d'une serge adéquate, soit comprenant des éléments réalisés dans un matériau de plus grande densité, soit étant elle-même réalisée dans un matériau de plus grande densité.Thus, the balance wheel according to the invention is made of a material allowing the use of a simple manufacturing process while having a coefficient of thermal expansion allowing it to be paired with a balance spring in monocrystalline quartz, and/or in metal or in silicon. , preferably monocrystalline quartz. The balance wheel according to the invention also makes it possible to have at least arms having a coefficient of thermal expansion allowing it to be paired with a monocrystalline quartz hairspring, and/or metal or silicon, while having a high inertia while keeping a compact and aesthetic serge geometry, of small volume, using a suitable serge, either comprising elements made of a material of greater density, or being itself made of a higher density material.

Claims (15)

  1. Process for producing a balance wheel (1) for a timepiece comprising a felloe (2), a hub (4) and at least one arm (8) connecting the hub (4) to said felloe (2), the felloe (2), the hub (4) and the arm (8) being made of a metal alloy, said process comprising the following steps:
    a) making a mould having the negative shape of the balance wheel (1)
    b) getting hold of a metal alloy, which has a thermal expansion coefficient of less than 25 ppm/°C and being able to be in an at least partly amorphous state when it is heated to a temperature between its glass transition temperature and its crystallisation temperature
    c) putting the metal alloy into the mould, said metal alloy being heated to a temperature between its glass transition temperature and its crystallisation temperature so as to be hot moulded and to form a balance wheel
    d) cooling said metal alloy to obtain a balance wheel (1) made of said metal alloy
    e) releasing the balance wheel (1) obtained in step d) from its mould;
    the process being characterised in that it includes a step for over-moulding flexible centring components (16, 17) in the hub (4).
  2. Process according to the preceding claim, characterized in that it includes a step to over-mold first inertia adjusting components (10) in the felloe (2), said first inertia adjusting components (10) being made of a first material having a density that is greater than the density of the aforesaid metal alloy.
  3. Process for producing a balance wheel of a timepiece comprising a felloe (2), a hub (4) and at least one arm (8) connecting the hub (4) to said felloe (2), the hub (4) and the arm (8) being made of a metal alloy, and the felloe (2) being made of a second material having a density that is greater than the density of said metal alloy of which the hub (4) and the arm (8) are made, said process including the following steps:
    a) making a mould having the negative shape of the balance wheel;
    a') inserting a felloe or felloe parts made of a material that has a density higher than the density of said metal alloy into the mould;
    b) getting hold of a metal alloy, which has a thermal expansion coefficient of less than 25 ppm/°C and being able to be in an at least partly amorphous state when it is heated to a temperature between its glass transition temperature and its crystallisation temperature;
    c) putting the metal alloy into the mould, said metal alloy being heated to a temperature between its glass transition temperature and its crystallisation temperature so as to be hot-moulded, and over-moulding the felloe or the parts of the felloe so as to mould a balance wheel with inserts;
    d) cooling said metal alloy so as to obtain a balance wheel with inserts;
    e) releasing the balance wheel obtained in step d) from its mould;
    the process being characterised in that it includes a step for over-moulding flexible centring components (16, 17) in the hub (4).
  4. Process according to one of the preceding claims, characterised in that the felloe (2) includes recesses (12) designed to receive second inertia adjusting and/or unbalance compensating components (14, 15).
  5. Process according to one of the preceding claims, characterised in that the felloe (2) includes recesses (12) designed to receive decorative and/or luminescent elements.
  6. Process according to the preceding claim, characterised in that said integrated flexible centring components (16) are located on the inside circumference of the hub (4).
  7. Process according to one of the preceding claims, characterised in that it includes a step to over-mould third flexible inertia adjusting components (19, 20, 22a, 22b) in the arm (8).
  8. Process according to one of the preceding claims, characterised in that the mould has microstructures forming a decor or a photonic network.
  9. Process according to one of the preceding claims, characterised in that said metal alloy is based on an element selected from among the group comprising platinum, zirconium, titanium, palladium, nickel, aluminium and iron.
  10. Process according to one of the preceding claims, characterised in that said metal alloy is based on platinum and has a thermal expansion coefficient of less than 12 ppm/°C, preferably between 8 ppm/°C and 12 ppm/°C.
  11. Process according to claim 10, characterised in that the metal alloy based on platinum is made, in atomic % values, of
    - a base of platinum, whose concentration constitutes the balance,
    - 13 to 17% copper
    - 3 to 7% nickel
    - 20 to 25% phosphorus.
  12. Process according to one of claims 1 to 9, characterised in that said metal alloy is based on zirconium and has a thermal expansion coefficient that is smaller than 12 ppm/°C, preferably between 8 ppm/°C and 11 ppm/°C.
  13. Process according to claim 12, characterised in that the metal alloy based on zirconium is made, in atomic % values, of
    - a base of zirconium, whose concentration constitutes the balance,
    - 14 to 20% copper
    - 12 to 13% nickel
    - 9 to 11% aluminium
    - 2 to 4 % niobium.
  14. Process according to one of claims 1 to 9, characterised in that said metal alloy is based on palladium and has a thermal expansion coefficient that is less than 20 ppm/°C, preferably between 13 ppm/°C and 18 ppm/°C.
  15. Process according to claim 14, characterised in that the metal alloy based on palladium is made, in atomic % values, of
    - a base of palladium, whose concentration constitutes the balance,
    - 25 to 30% copper
    - 8 to 12% nickel
    - 18 to 22% phosphorus.
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CN206178347U (en) 2015-11-13 2017-05-17 尼瓦洛克斯-法尔股份有限公司 Balance, clock cassette mechanism and clock and watch spare with inertia is adjusted
EP3170579A1 (en) * 2015-11-18 2017-05-24 The Swatch Group Research and Development Ltd. Method for manufacturing a part from amorphous metal
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EP3217229B1 (en) 2016-03-07 2020-01-01 Montres Breguet S.A. Adjustable auxiliary thermal compensation system
EP3252545B1 (en) 2016-06-03 2019-10-16 The Swatch Group Research and Development Ltd. Timepiece mechanism with balance wheel inertia adjustment

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JP2019113533A (en) 2019-07-11
JP6770049B2 (en) 2020-10-14
EP3502787A1 (en) 2019-06-26
EP3796102A1 (en) 2021-03-24
CN112965355A (en) 2021-06-15
EP3502787B1 (en) 2020-11-18
US20220163923A1 (en) 2022-05-26
CN109960137A (en) 2019-07-02
US11307535B2 (en) 2022-04-19
US20190196408A1 (en) 2019-06-27
CN109960137B (en) 2021-04-09
US11640140B2 (en) 2023-05-02

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