CH717841A2 - Clockwork mobile, in particular escapement mobile, with coated contact surface. - Google Patents

Abstract

The invention relates to a horological mobile, in particular an escapement mobile, comprising a substrate with a first material comprising at least nickel and phosphorus, which substrate is covered, at the level of at least one surface of the substrate of the mobile , by a coating of a second material comprising at least nickel and poorer in phosphorus than the first material, or devoid of phosphorus, and the second material constitutes the peripheral layer of the mobile at this at least one surface of the substrate.

Description

Field of invention

The invention relates to a micromechanical component, in particular a horological mobile with optimized contact surface, in particular an escapement mobile.

[0002] The invention also relates to a timepiece escapement mechanism comprising at least one non-magnetic mobile constituting an escape wheel or an anchor.

[0003] The invention relates to the field of horological mechanisms, and more particularly escapement mechanisms comprising at least one escape wheel and at least one lever, at least one of which is non-magnetic. .

Background of the invention

[0004] In Swiss lever watchmaking escapement mechanisms, the Swiss lever escapement wheels are historically made of nickel-plated steel, and are sensitive to magnetic fields.

[0005] Alternatives are known with materials such as nickel-phosphorus NiP12 implemented by the “LIGA” process (Lithographie und Galvano-Abformung“), which have a non-magnetic behavior.

[0006] However, the use of such materials, nickel-phosphorus, or the like, may prove to be sensitive in certain climatic conditions, which are likely to lead to a deterioration in performance, in particular in terms of amplitude regularity, stops , or even aging, especially when the two opposing components of the friction torque are made of similar LIGA materials. The deposition of a superficial layer of gold, although favorable to the stabilization of the amplitude, does not solve the overall problem, or even aggravates the aging phenomenon, and can influence the stability of the rate.

Summary of the invention

[0007] The invention proposes to solve the technical problem of the behavior of the usual watch lubricant, and more particularly to guarantee an epilame effect, under the usual climatic conditions, on components made of LIGA NiP12, or similar, non-ferromagnetic, by particular on Swiss lever escapement wheels.

[0008] To this end, the invention relates to a micromechanical component with optimized contact surface, in particular a horological mobile, in particular an escapement mobile, according to claim 1.

[0009] The invention also relates to a timepiece escapement mechanism comprising at least one such mobile constituting an escape wheel or an anchor.

Detailed Description of Preferred Embodiments

The invention relates to the field of micromechanical components, and more particularly to watch mobiles.

[0011] The invention proposes to solve in particular the technical problem of the behavior of the usual watch lubricant, in the usual climatic conditions, on components made of LIGA NiP12, or similar, non-ferromagnetic, in particular on wheels of a mechanism lever escapement.

[0012] The contact between the lever in ruby and the tooth of the escapement wheel is particularly sensitive.

[0013] This is in particular to prevent any pollution of the anchor, in particular of the anchor fork, and to ensure the presence of lubricant on the contact surfaces of the escape wheel and the anchor. , and to reduce the aging of the escape wheel and pallet.

[0014] The main problem is the loss of epilame effect on the plate of the escape wheel, which causes the oil to spread and a loss of lubrication on contact between the tooth of the wheel and the ruby ring.

[0015] The stability of the lubrication in contact between the lifts of the anchor and the escape wheel must make it possible to guarantee the constancy of the amplitude.

For this purpose, the addition of a layer of galvanic nickel (Ni), or of chemical nickel (for example NiP6-9), or of nickel-boron deposited by chemical means, on an escapement wheel in LIGA NiP12 greatly improves movement performance. It has been demonstrated by various tests that this significant improvement is linked to better resistance of the epilame in climatic conditions, in particular temperature and humidity, better attachment of the epilame to the material, when the quantity of phosphorus on the surface is reduced, and the holding of the lubricant is all the better as the quantity of phosphorus is low. In particular, the tribological behavior of a surface layer of pure nickel is better than that of an NiP6-9 layer, the behavior of which is itself better than that of an NiP12 or NiP13 layer.

[0017] Alternatively, the galvanic nickel coating may be an alloy, for example Ni-Fe, or Ni-W, or other.

[0018] Thus the invention relates to a micromechanical component, in particular a clockwork mobile.

[0019] This component is advantageously achievable by a watch mobile manufacturing process, according to which a substrate is produced with a first material comprising at least nickel and phosphorus, this substrate is shaped to the geometry of the mobile, and the substrate is coated, by galvanic and/or chemical means, at the level of at least one surface of the substrate of the mobile, with at least one second thin material, in particular less than 10 micrometers, which constitutes the peripheral layer of the mobile at this at least one surface of the substrate of the mobile, and which comprises at least nickel and which is poorer in phosphorus than the first material, or which comprises nickel and is devoid of phosphorus.

[0020] More particularly, this first material is non-magnetic.

[0021] More particularly, this second material is non-magnetic.

[0022] Note that nickel is not non-magnetic, and that NiP6-9% is not necessarily so, it is the low thickness of the deposit that keeps the part non-magnetic.

In a particular embodiment, the substrate is a nickel-phosphorus of NiPx formulation, with x between 1% and 15% by mass, terminals included, or more particularly with x between 10% and 15% by mass, terminals included, this last range making it possible to guarantee the non-magnetic character of the coating.

This substrate is covered with a coating low in phosphorus, according to the invention, the thickness of which is more particularly and not limited to between 0.2 micrometer and 5.0 micrometer, terminals included, and, more particularly still between 0.2 micrometer and 2.0 micrometer, terminals included.

The covering treatment with a coating low in phosphorus, according to the invention, can be done galvanically.

It is possible to apply a heat treatment to the substrate before the deposition operation, in particular galvanic, or even to apply a heat treatment to the assembly formed by the substrate and its coating after the operation. deposit, in particular galvanic.

[0027] It is also possible to apply a chemical treatment to the substrate to modify its surface characteristics so as to facilitate the adhesion of the coating, in particular by galvanic means.

Alternatively, the coating treatment with a coating low in phosphorus, according to the invention can be done chemically, according to a method of applying chemical nickel, which can be pure nickel, or a nickel- phosphorus low in phosphorus, for example NiP6-9, with 6% to 9% by mass of phosphorus, or even a nickel-boron NiB.

[0029] The addition of a layer of nickel, or NiP6-9, or NiB, makes it possible to increase the stability of the epilame in climatic conditions, the grip of the epilame and therefore the resistance of n any usual watchmaker's lubricant.

More particularly, the epilame used is a fluorine-based formulation.

[0031] The lubricant can also be deposited on an escapement wheel set with a complement in the form of a paste based on molybdenum disulphide MoS2, which acts as a lubricant and a lubricant sponge.

[0032] Advantageously, the escape wheel concerned has a geometry making it possible to reduce the contact surfaces to a minimum, for example the use of a cradled anchor is preferred, which is an anchor whose active faces of the fork , intended to come into contact with the ellipse and the stops, are rounded, which makes it possible to have a contact point instead of a contact line.

[0033] An innovative embodiment of an escapement mechanism comprises an anchor in LIGA, or an anchor of which at least the pallets are in LIGA. In such a case, the LIGA parts of the anchor are subject to the same problem, and the same solution is applicable.

The invention makes it possible to guarantee normal aging conditions, constant amplitude, and the absence of shutdown, in particular in the presence of cradled LIGA nickel-phosphorus anchors, which provide better shock resistance. than silicon anchors, for example.

[0035] Thus, preferably, a method for manufacturing such a micromechanical component, in particular a clockwork mobile, is implemented, according to which: a substrate is manufactured with a first material comprising at least nickel and phosphorus, and this substrate is coated, at at least one surface of the substrate of the mobile, with at least one second material which constitutes the peripheral layer of the mobile at this at least one surface of the substrate; this at least one second material comprises at least nickel, and is poorer in phosphorus than the first material, or else this at least one second material comprises nickel and is devoid of phosphorus.

More particularly, this coating of the substrate is carried out, at the level of at least one surface adjoining a friction surface of the mobile, with this at least one second material, which constitutes the peripheral layer of the mobile at the level of this at least one surface adjoining a friction surface. By „adjoining“ we mean that the two surfaces are contiguous, or at least tangent, their intersection is not empty, even if it is limited to an isthmus of very small section.

[0037] Such a micromechanical component, in particular a clockwork mobile, thus comprises an optimized contact surface.

[0038] This micromechanical component, and more particularly this clockwork mobile, comprises a substrate in a first material comprising at least nickel and phosphorus. According to the invention, this substrate is covered, at at least one surface of the mobile substrate, by a coating of a second material comprising at least nickel and poorer in phosphorus than the first material, or devoid of phosphorus , and the second material constitutes the peripheral layer of the mobile at the level of the at least one surface of the substrate.

[0039] More particularly, the coating of the substrate covers the substrate at surfaces of the mobile other than the guide surfaces of the mobile for its pivoting or for its guidance according to a single degree of freedom. More particularly still, the coating of the substrate covers the substrate at the level of all the surfaces of the mobile other than the guide surfaces.

[0040] More particularly, the substrate is covered, at at least one surface adjoining a friction surface of the mobile, by a coating of a second material comprising at least nickel and lower in phosphorus than the first material, or devoid of phosphorus, and the second material constitutes the peripheral layer of the mobile at the level of the at least one surface adjoining a friction surface. More particularly, the coating of the substrate covers the substrate at the level of surfaces adjoining friction surfaces of the mobile other than the guide surfaces of the mobile for its pivoting or for its guidance according to a single degree of freedom. More particularly still, the coating of the substrate covers the substrate at the level of all the surfaces adjoining the friction surfaces of the mobile other than the guide surfaces of the mobile for its pivoting or for its guidance according to a single degree of freedom. Even more particularly, the coating of the substrate covers the substrate at all the surfaces adjoining the sliding surfaces of the mobile including the guide surfaces of the mobile for its pivoting or for its guidance according to a single degree of freedom.

More particularly, the coating of the substrate covers the substrate at all the surfaces of the mobile including the guide surfaces of the mobile for its pivoting or for its guidance according to a single degree of freedom.

[0042] More particularly, the first material comprises only nickel and phosphorus.

More particularly, the first material comprises phosphorus with a mass proportion of between 1% and 15%, limits included. More particularly still, the first material is non-magnetic and comprises phosphorus with a mass proportion of phosphorus of between 10% and 15%, limits included.

More particularly, the second material is chosen with a mass proportion of phosphorus less than or equal to 15%. More particularly, the second non-magnetic material is chosen with a mass proportion of phosphorus of between 10% and 15%, limits included.

In an alternative, the second material is chosen with a mass proportion of phosphorus of between 6% and 12%, limits included. In another alternative, the second material is chosen with a mass proportion of phosphorus of between 1% and 6%, limits excluded. In yet another alternative, the second material is chosen with a mass proportion of phosphorus of between 0% and 1%, limits included.

More particularly, the second material comprises only nickel and phosphorus.

More particularly, the second material comprises boron. More particularly still, the second material comprises only nickel and boron.

More particularly, the second material consists of pure nickel.

More particularly, the second material has a thickness of less than 10 micrometers. More particularly still, the second material has a thickness of less than 5 micrometers. Even more particularly, the second material has a thickness comprised between 0.2 micrometer and 2.0 micrometer, limits included.

In yet another variant, the second material is applied with a thickness between zero and 0.2 micrometer, limits excluded, in particular in the vicinity of 0.1 micrometer.

[0051] The invention also relates to a clockwork mechanism, in particular but not limited to an escapement mechanism. In this advantageous application, the timepiece escapement mechanism comprises at least one such wheel set, constituting an escape wheel or an anchor. And this mobile comprises a substrate with a first material comprising at least nickel and phosphorus, and whose substrate is covered, at all the surfaces adjoining the rubbing surfaces of the mobile, by a coating of a second material comprising at least nickel and poorer in phosphorus than the first material, or devoid of phosphorus, and the second material constitutes the peripheral layer of the mobile at the level of the surfaces adjoining the rubbing surfaces that the mobile has to cooperate with an anchor or an escapement wheel or a pendulum.

Claims (18)

1. Watch mobile comprising a substrate in a first material comprising at least nickel and phosphorus, characterized in that said substrate is covered, at at least one surface of the substrate of said mobile, by a coating of a second material comprising at least nickel and poorer in phosphorus than said first material, or devoid of phosphorus, and in that said second material constitutes the peripheral layer of said mobile at the level of said at least one surface of the substrate of said mobile. 2. Mobile according to claim 1, characterized in that said substrate is covered, at at least one surface adjoining a friction surface of said mobile, by a coating of said second material, which constitutes the peripheral layer of said mobile at said at least one surface adjoining a friction surface of said mobile. 3. Mobile according to claim 1 or 2, characterized in that said first material comprises phosphorus with a mass proportion of between 1% and 15%, limits included. 4. Mobile according to claim 3, characterized in that said first material is non-magnetic and comprises phosphorus with a mass proportion of phosphorus of between 10% and 15%, limits included. 5. Mobile according to one of claims 1 to 4, characterized in that said first material comprises only nickel and phosphorus. 6. Mobile according to one of claims 1 to 5, characterized in that said second material is non-magnetic and comprises a mass proportion of phosphorus of between 10% and 15%, limits included. 7. Mobile according to one of claims 1 to 5, characterized in that said second material comprises a mass proportion of phosphorus of between 6% and 12%, limits included. 8. Mobile according to one of claims 1 to 5, characterized in that said second material comprises a mass proportion of phosphorus of between 1% and 6%, limits excluded. 9. Mobile according to one of claims 1 to 5, characterized in that said second material comprises a mass proportion of phosphorus between 0% and 1%, limits included. 10. Mobile according to claim 9, characterized in that said second material is devoid of phosphorus. 11. Mobile according to one of claims 1 to 5, characterized in that said second material comprises only nickel and phosphorus. 12. Mobile according to one of claims 1 to 10, characterized in that said second material comprises boron. 13. Mobile according to one of claims 1 to 5, characterized in that said second material comprises only nickel and boron. 14. Mobile according to one of claims 1 to 5, characterized in that said second material consists of pure nickel. 15. Mobile according to one of claims 1 to 14, characterized in that said second material has a thickness of less than 10 micrometers. 16. Mobile according to claim 15, characterized in that said second material has a thickness of less than 5 micrometers. 17. Mobile according to claim 16, characterized in that said second material has a thickness of between 0.2 micrometer and 2.0 micrometer, limits included. 18. Timepiece escapement mechanism comprising at least one mobile according to one of claims 1 to 17, constituting an escape wheel or an anchor, characterized in that said mobile comprises a substrate with a first material comprising at least nickel and phosphorus, and of which said substrate is covered, at all the surfaces adjoining the rubbing surfaces of said mobile, by a coating of a second material comprising at least nickel and lower in phosphorus than said first material, or devoid of phosphorus, and in that said second material constitutes the peripheral layer of said mobile at the level of said surfaces adjoining rubbing surfaces that said mobile comprises in order to cooperate with an anchor or an escape wheel or a balance wheel.