This application claims priority from European Patent Application No. 15195348.6 filed on Nov. 19, 2015, the entire disclosure of which is hereby incorporated herein by reference.
The invention concerns a timepiece component, comprising a core made of material suitable for electroforming, which core is, at least locally, coated with a surface layer of gold or gold alloy, to improve its tribological behaviour in the areas including said surface layer of gold or gold alloy.
The invention also concerns a method for fabricating a timepiece component.
The invention also concerns a watch comprising at least one such component.
The invention concerns the field of timepiece mechanisms, and in particular escapement mechanisms.
It is always difficult to ensure lubrication of timepiece mechanisms and to maintain lubrication over time. Degradation of the original lubricant generally means that watch users have to send the watches back for maintenance.
WO 2009/083487 in the name of NIVAROX-FAR SA discloses a method for fabricating a metal microstructure, by superposing at least two layers of different materials, in a UV-LIGA (Lithographie Galvanik Abformung) type method.
CH Patent 703794 in the name of SEIKO Instruments Inc. discloses the manufacture of a pallet-lever, with an electroformed guard pin.
CH Patent 681370 in the name of Estoppey-Reber and GET discloses a gold-based lubricating composition on a thin nickel-phosphorus layer.
The invention proposes to improve the tribological behaviour of certain components of timepiece mechanisms, in particular escapement mechanisms.
To this end, the invention concerns a timepiece component according to claim 1.
The invention also concerns a watch comprising at least one such component.
The invention also concerns a method for fabricating a timepiece component according to claim 12.
Other features and advantages of the invention will appear upon reading the following detailed description, with reference to the annexed drawings, in which:
The invention concerns a timepiece component 1 with improved tribology.
This component 1 includes an electroformed core 2 made of a material suitable for electroforming, which core 2 is, at least locally, coated with a surface layer 3 of gold or gold alloy, to improve its tribological behaviour in the areas 4 including the surface layer 3 of gold or gold alloy.
According to the invention, core 2 is made of only one type of material, and the material of electroformed core 2 includes nickel.
More particularly, core 2 is hollow.
More particularly, the material of electroformed core 2 includes cobalt.
More particularly, the material of electroformed core 2 includes tungsten.
More particularly, the material of electroformed core 2 includes nickel-phosphorus (NiP).
More particularly, the material suitable for electroforming includes 8 to 15 mass percent of phosphorus in the nickel-phosphorus (NiP) contained therein.
More particularly, core 2 contains only nickel-phosphorus (NiP).
This variant embodiment wherein solid core 2 contains only nickel-phosphorus (NiP) is easy to implement, of reasonable cost and this material lends itself well to the adhesion of surface layer 3 of gold or gold alloy. More particularly, in this case core 2 has a thickness comprised between 40 micrometres and 1000 micrometres.
Preferably, core 2 is produced by an electroforming process, not described here since it is well known to those skilled in the art of horology/jewelery.
In a variant, core 2 is produced by a LIGA method.
More particularly, gold or gold alloy surface layer 3 is a layer having a thickness less than or equal to 1.0 micrometres.
More particularly, gold or gold alloy surface layer 3 is a layer of gold alloy containing at least 50 mass percent of gold.
More particularly, gold or gold alloy surface layer 3 is a layer of gold alloy containing at least 75 mass percent of gold.
More particularly, gold or gold alloy surface layer 3 is made of 18 carat gold alloy containing at least 75 mass percent of gold, and containing copper and silver.
More particularly, surface gold or gold alloy layer 3 is a layer of gold alloy containing a maximum of 77 mass percent of gold.
More particularly, surface gold or gold alloy layer 3 is a layer of gold alloy which may contain up to 100% gold. In a particular advantageous implementation of the invention, the deposited gold is virtually pure, and forms at least 99.0 mass percent of surface layer 3. The latter may also include traces of other materials, and more particularly contain traces of nickel or cobalt, with less than 0.5 mass percent of nickel and/or cobalt.
More specifically, component 1 is a movement component arranged to transmit a force and/or a torque by friction, such as a wheel, pinion, pallet lever (plate and/or guard pin and/or lifting pieces), impulse pin, spring element, or more particularly a component of an escapement mechanism, among the usual escapement components: balance, escape wheel, escape pinion, pallet lever, impulse pin.
The invention also concerns a watch 100 including at least one component 1 of this type.
The invention also concerns a method for manufacturing a timepiece component 1, which includes the steps consisting in:
More particularly, the coating of solid core 2 with a gold or gold alloy surface layer 3 is effected over the entire surface of the core.
More particularly, the coating of solid core 2 with a gold or gold alloy surface layer 3 is achieved by an electroplating technique and/or PVD coating.
More particularly, after solid core 2 has been shaped and before or after solid core 2 is coated with a gold or gold alloy surface layer 3 to form a component 1, a heat treatment step 40 is effected on solid core 2 or on component 1.
More particularly, the coating of solid core 2 or of component 1 depending on the case, by a gold or gold alloy surface layer 3 is effected in the form of a surface layer 3 with a thickness less than or equal to 1.0 micrometres.
More particularly, surface layer 3 has a thickness comprised between 0.85 and 1.00 micrometres.
More particularly, the heat treatment is effected at a temperature comprised between 150° C. and 600° C. for a duration of between 30 minutes and 6 hours. More particularly, the heat treatment is effected at a temperature comprised between 150° C. and 600° C. for a duration of between 30 minutes and 6 hours. More particularly, this heat treatment is effected at a temperature comprised between 200° C. and 600° C.
More particularly, the heat treatment is a surface hardening heat treatment of solid core 2.
More particularly, the composition contains nickel, more particularly the composition is prepared with a nickel base.
More particularly, the composition contains nickel-phosphorus (NiP), more particularly the composition is prepared with a nickel-phosphorus (NiP) base.
More particularly, the composition includes 8 to 15 mass percent of phosphorus in the nickel-phosphorus (NiP) contained therein.
More particularly, the composition includes 13 to 15 mass percent of phosphorus in the nickel-phosphorus (NiP) contained therein.
More particularly, core 2 is made of only one type of material.
More particularly, the composition is prepared only with nickel-phosphorus (NiP).
More particularly, the composition contains cobalt and/or tungsten.
More particularly, the thickness of core 2 is comprised between 40 and 1000 micrometres. More particularly, the thickness of core 2 is comprised between 40 and 500 micrometres.
More particularly, the thickness of the nickel-phosphorus layer, if solid core 2 contains several layers of materials superposed on each other, is comprised between 1 and 50 micrometres.
More particularly, if solid core 2 contains several layers of materials superposed on each other, the layer receiving gold or gold alloy surface layer 3 is a nickel-phosphorus layer.
More particularly, component 1 is a movement component arranged to transmit a force and/or a torque by friction, such as a wheel, pinion, pallet lever (plate and/or guard pin and/or lifting pieces), impulse pin, spring element, or more particularly a component of an escapement mechanism, selected from a balance, escape wheel, escape pinion, pallet lever, impulse pin.
Number | Date | Country | Kind |
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15195348.6 | Nov 2015 | EP | regional |