A micromechanical component, the surface of which is optimized, in particular an escapement wheel, in particular a clock wheel.

Abstract

A micromechanical component, in particular an escapement wheel, in particular a clock wheel, having a substrate with a first material containing at least nickel and phosphorus, the substrate being covered on at least one surface of the wheel substrate with a coating of a second material containing at least nickel and containing less phosphorus than the first material or containing no phosphorus, the second material constituting a peripheral layer of the wheel at this at least one surface of the substrate.

Description

[Technical field]

[0001] The invention relates to a micromechanical component, in particular an escapement wheel, in particular a timepiece wheel, the surface of which is optimized.

[0002] The invention also relates to a timepiece escapement mechanism having at least one wheel of non-magnetic nature constituting an escape wheel or pallet.

[0003] The present invention relates to the field of timepiece mechanisms, and more particularly to an escapement mechanism having at least one escapement wheel and at least one pallet, at least one of which is of a non-magnetic nature. [Background technology]

[0004] In Swiss lever watch escapement mechanisms, the Swiss lever escape wheel has historically been made of nickel-plated steel and responds to a magnetic field.

[0005] Alternatives are known that use materials such as nickel-phosphorus NiP12, which behave non-magnetically and are implemented by the "LIGA" (Lithographie und Galvano-Abformung, meaning Lithography, Electroplating, Moulding) method.

[0006] However, the use of such materials, such as nickel-phosphorus or similar, can be highly susceptible to certain weather conditions, which is likely to lead to a decrease in performance, particularly in terms of amplitude invariance, stoppage, or even aging, especially when two opposing components of friction torque occur in similar LIGA materials. Summary of the Invention [Problem to be solved by the invention]

[0007] The invention proposes to solve the technical problem of the resistance of normal horological lubricants and, more specifically, of guaranteeing their epilamé effect, under normal climatic conditions, on components made of non-ferromagnetic LIGA NiP12 or similar, in particular on Swiss lever escape wheels. [Means for solving the problem]

[0008] For this purpose, the invention relates to a micromechanical component, the surface of which is optimized, in particular an escapement wheel, in particular a clock wheel, according to claim 1 .

[0009] The invention also relates to a timepiece escapement mechanism having at least one such wheel constituting an escapement wheel or pallet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention relates to the field of micromechanical components, and more particularly to clock wheels.

[0011] The invention proposes to solve the technical problem of the resistance, under normal climatic conditions, of normal horological lubricants on components made of LIGA NiP12 or similar, which are non-ferromagnetic, in particular on the wheels of the Swiss lever escapement mechanism.

[0012] In Swiss-lever watch escapement mechanisms, contact between the ruby-made feed pawl of the pallet and the teeth of the escape wheel is particularly sensitive, as is contact between the fork and the pallet-stone pin or between the fork and the pallet banking-pin.

[0013] In particular, this concerns ensuring the presence of lubricant on the contact surfaces between the escape wheel and the pallet, and reducing deterioration of the escape wheel and the pallet over time.

[0014] The main problem is the loss of the epirame effect on the plates of the escape wheels, which causes the oil to disperse and lose lubricant at the point of contact between the teeth of the wheels and the feed pawls made of ruby.

[0015] The persistence of lubricant at the point of contact between the pallet feed pawl and the escape wheel must make it possible to ensure consistency of amplitude.

[0016] For this purpose, the addition of a coating in the form of a layer of galvanic nickel (Ni) or chemical nickel (e.g. NiP6-9), or even chemically deposited nickel-boron, which is preferred, on the escape wheel made of LIGA NiP12, makes it possible to significantly improve the performance of the movement.

[0017] Indeed, various tests have demonstrated that this significant improvement is related to a better resistance of the epirame in given weather conditions, for example 50 degrees Celsius and a humidity level of 90%. The inventors have observed a better adhesion of the epirame on this material when the amount of phosphorus on the surface is reduced. As a result, the resistance of the lubricant remains better even when the amount of phosphorus is low.

[0018] In one variation, the galvanic nickel coating may be an alloy, such as Ni-Fe or Ni-W.

[0019] The invention therefore relates to a micromechanical component, in particular a clock wheel.

[0020] This component can advantageously be produced by a method for manufacturing a clock wheel, according to which a substrate is produced using a first material comprising at least nickel and phosphorus, this substrate is shaped to have the geometric shape of the car, and coating of the substrate is carried out galvanically and / or chemically, on at least one surface of the car substrate, with at least one second material having a small thickness, in particular less than 10 micrometers, this second material constituting a peripheral layer of the car at this at least one surface of the car substrate, this second material comprising at least nickel and which comprises less phosphorus than the first material, or this second material comprises nickel but not phosphorus.

[0021] More specifically, this first material is non-magnetic.

[0022] More specifically, the second material is non-magnetic. More specifically, the second material has non-magnetic properties.

[0023] It should be noted that nickel is not non-magnetic, and that 6-9% NiP is not necessarily non-magnetic, but rather the thickness of the deposit that imparts the non-magnetic properties to the part will be small.

[0024] In a particular embodiment, the substrate is nickel-phosphorus of the formula NiPx, where x is between 1% and 15% by weight or more specifically where x is between 10% and 15% by weight, the latter range making it possible to ensure the non-magnetic nature of the coating.

[0025] The coating over the substrate contains low phosphorus and has a thickness, without limitation, between 0.2 micrometers and 10.0 micrometers, and more specifically, between 0.2 micrometers and 2.0 micrometers.

[0026] Preferably, the coating has a thickness of 0.5 micrometers.

[0027] Coating processes using low phosphorus containing coatings according to the present invention can be carried out galvanically.

[0028] It is possible to apply a heat treatment to the substrate prior to the deposition operation, in particular a galvanic one, or to apply a heat treatment to the assembly formed by the substrate and its coating, in particular after the deposition operation, in particular a galvanic one.

[0029] It is also possible to apply chemical treatments to the substrate in order to modify its surface characteristics in order to promote adhesion of the coating, particularly galvanic.

[0030] Alternatively, the coating process with low phosphorus or phosphorus-free coatings according to the invention can be carried out chemically according to the method for adding chemical nickel, which can be pure nickel or low phosphorus nickel-phosphorus, e.g. NiP6-9, containing 6% to 9% phosphorus by weight, or even nickel-boron, NiB.

[0031] The addition of a layer of nickel or a layer of NiP6-9 or NiB makes it possible to improve the durability of the epiramé in all weather conditions, the adhesion of the epiramé and therefore the resistance of any conventional horological lubricants.

[0032] More specifically, the epilamme used is a fluorine-based formulation.

[0033] Furthermore, the lubricant can be applied onto the escapement wheel by means of a supplement in the form of a paste based on molybdenum disulfide MoS2, which acts as a lubricant and lubricant sponge.

[0034] Advantageously, the associated escapement wheel has a geometry which makes it possible to reduce the contact surface to a minimum, for example it is preferable to use a rounded pallet, which is an pallet that rounds the active surface of the fork intended to be brought into contact with the plate pin and the banking pin, making it possible to have a contact point instead of a contact line.

[0035] An innovative embodiment of the escapement mechanism has a pallet made of LIGA, or at least a pallet whose pallet stone is made of LIGA. In such a case, the LIGA part of the pallet suffers from the same problems and the same solutions are applicable.

[0036] The invention makes it possible to guarantee normal ageing conditions, consistency of amplitude and no breakdowns, in particular in the presence of rounded LIGA nickel-phosphorus ankles, which guarantee better shock resistance than, for example, silicon ankles.

[0037] Thus, in a preferred manner, a method for manufacturing such a micromechanical component, in particular a clock wheel, comprises the following steps: - the substrate is manufactured using a first material comprising at least nickel and phosphorus; - the coating of said substrate is carried out on at least one surface of the substrate of the vehicle with at least one second material, said second material constituting a peripheral layer of the vehicle at said at least one surface of the substrate, - the at least one second material comprises at least nickel and less phosphorus than the first material, or the at least one second material comprises nickel and no phosphorus; This is carried out by.

[0038] More specifically, the coating of the substrate is carried out with the at least one second material on at least one surface adjacent to the friction surface of the vehicle, the second material constituting a peripheral layer of the vehicle at the at least one surface adjacent to the friction surface, "adjacent" meaning that the two surfaces are in contact or at least in a tangential relationship, with no gaps between them, even limited to very small valleys.

[0039] Thus, such a micromechanical component, in particular a clock wheel, has a surface that is optimized.

[0040] This micromechanical component, more specifically a clock wheel, has a substrate which is a first material containing at least nickel and phosphorus. According to the invention, this substrate is covered, on at least one surface of the substrate of the car, with a coating of a second material which contains at least nickel and which contains less phosphorus than the first material or which does not contain phosphorus, the second material constituting, at at least one surface of the substrate, the peripheral layer of the car.

[0041] More specifically, the substrate coating covers the substrate on the surfaces of the vehicle that are not the guide surfaces of the vehicle where the substrate pivots or guides according to one degree of freedom, and more specifically, the substrate coating covers the substrate on the entirety of the surfaces of the vehicle that are not the guide surfaces.

[0042] More specifically, the substrate is covered, on at least one surface adjacent to the friction surface of the vehicle, with a coating of a second material that contains at least nickel and contains less phosphorus than the first material or contains no phosphorus, the second material constituting a peripheral layer of the vehicle at the at least one surface adjacent to the friction surface.

[0043] More specifically, the coating covers the substrate on at least one surface adjacent to the friction surface of the vehicle that is not the guide surface of the vehicle where the coating pivots or provides guidance according to one degree of freedom.

[0044] More specifically, the substrate coating covers the substrate over the entire surface adjacent to the friction surface of the vehicle that is not the guide surface of the vehicle where the substrate pivots or provides guidance according to one degree of freedom.

[0045] More specifically, the substrate coating covers the substrate over the entire surface adjacent the friction surface of the vehicle, including the vehicle guide surface where the substrate pivots or provides guidance according to one degree of freedom.

[0046] More specifically, the substrate coating covers the substrate over the entire surface of the vehicle, including the vehicle's guide surfaces where it pivots or provides guidance according to one degree of freedom.

[0047] More specifically, the first material includes only nickel and phosphorus.

[0048] More specifically, the first material comprises phosphorus having a percentage by weight between 1% and 15%.More specifically, the first material is non-magnetic and comprises phosphorus having a percentage by weight between 10% and 15%.

[0049] More specifically, a second material is selected that has a phosphorus percentage by weight of 15% or less, and even more specifically, a second non-magnetic material is selected that has a phosphorus percentage by weight between 10% and 15%.

[0050] In one alternative, the second material is selected to have a percentage of phosphorus between 6% and 12% by weight. In another alternative, the second material is selected to have a percentage of phosphorus between 1% and 6% by weight. In another alternative, the second material is selected to have a percentage of phosphorus of 1% or less by weight.

[0051] More specifically, the second material includes only nickel and phosphorus.

[0052] More specifically, the second material includes boron.More specifically, the second material includes only nickel and boron.

[0053] More specifically, the second material is made of pure nickel.

[0054] The coating has a thickness of less than 10 micrometers. More specifically, the coating has a thickness of less than 5 micrometers. More specifically, the coating has a thickness of between 0.2 micrometers and 2.0 micrometers.

[0055] Preferably the coating has a thickness of 0.5 micrometers.

[0056] In another variation, the coating is applied at a thickness of less than 0.2 micrometers, specifically about 0.1 micrometers.

[0057] The invention further relates to a timepiece mechanism, in particular but not exclusively an escapement mechanism, in this advantageous application the timepiece escapement mechanism has at least one such wheel, for example formed by an escape wheel or an anchor.

[0058] The vehicle has a substrate made of a first material containing at least nickel and phosphorus, and the substrate is covered over the entire surface adjacent to the friction surface of the vehicle with a coating made of a second material containing at least nickel and either less phosphorus than the first material or no phosphorus.

[0059] A second material constitutes the peripheral layer of the wheel at its surface adjacent to the friction surfaces contained within the wheel for cooperating with the pallet or escape wheel or the balance wheel.

[0060] The car can advantageously receive on its friction surfaces a lubricating substance, for example an oil or a synthetic grease, adapted to precise micro-engineering applications, known to those skilled in the art of horology. Such a lubricating substance can be mixed with a paste based on molybdenum disulfide MoS2.

[0061] Furthermore, the vehicle may advantageously receive an epilamme layer on at least one surface of the coating that is not its friction surface, to allow better resistance of the lubricating substance.

Claims

1. A clock car having a substrate of a first material containing at least nickel and phosphorus, said substrate being covered, on at least one surface of said substrate, with a coating of a second material containing at least nickel and less phosphorus than said first material, said second material constituting a peripheral layer of said car at said at least one surface of said substrate of said car, The second material is non-magnetic and contains between 10% and 15% phosphorus by weight.

2. 2. The vehicle of claim 1, wherein the substrate is covered on at least one surface adjacent to a friction surface of the vehicle with a coating of the second material, the second material constituting the peripheral layer of the vehicle at the at least one surface adjacent to a friction surface of the vehicle.

3. 2. The vehicle according to claim 1, characterized in that the first material is non-magnetic and contains phosphorus in a proportion of between 10% and 15% by weight.

4. 2. The vehicle of claim 1, wherein the first material comprises only nickel and phosphorus.

5. A clock car having a substrate of a first material containing at least nickel and phosphorus, said substrate being covered, on at least one surface of said substrate, with a coating of a second material containing at least nickel and less phosphorus than said first material, said second material constituting a peripheral layer of said car at said at least one surface of said substrate of said car, The second material comprises between 6% and 12% phosphorus by weight.

6. A clock car having a substrate of a first material containing at least nickel and phosphorus, said substrate being covered, on at least one surface of said substrate, with a coating of a second material containing at least nickel and less phosphorus than said first material, said second material constituting a peripheral layer of said car at said at least one surface of said substrate of said car, The second material comprises between 1% and 6% phosphorus by weight.

7. A clock car having a substrate of a first material containing at least nickel and phosphorus, said substrate being covered, on at least one surface of said substrate, with a coating of a second material containing at least nickel and less phosphorus than said first material, said second material constituting a peripheral layer of said car at said at least one surface of said substrate of said car, The second material comprises phosphorus in an amount of 1% or less by weight.

8. A clock car having a substrate of a first material containing at least nickel and phosphorus, said substrate being covered, on at least one surface of said substrate, with a coating of a second material containing at least nickel and less phosphorus than said first material, said second material constituting a peripheral layer of said car at said at least one surface of said substrate of said car, The second material comprises only nickel and phosphorus.

9. 8. The vehicle of claim 7, wherein the second material comprises boron.

10. 2. The vehicle of claim 1, wherein the second material has a thickness of less than 10 micrometers.

11. 11. The vehicle of claim 10, wherein the second material has a thickness between 0.2 micrometers and 2.0 micrometers.

12. 2. A timepiece escapement mechanism having at least one wheel according to claim 1, constituting an escape wheel or a pallet, characterized in that said wheel comprises a substrate having a first material containing at least nickel and phosphorus, said substrate of said wheel being covered, over the entirety of its surface adjacent to a friction surface of said wheel, with a coating of a second material containing at least nickel and less phosphorus than said first material, and said second material constituting the peripheral layer of said wheel at said surface adjacent to said friction surface contained within said wheel, for cooperating with a pallet or escape wheel or a balance wheel.

13. 13. The mechanism of claim 12, further comprising a lubricating material on said friction surfaces of said vehicle.

14. 14. The mechanism of claim 13, further comprising an epilamella layer on at least one surface of the coating that is not a friction surface thereof.