EP4258064A1 - Nichtmagnetische drehachse - Google Patents

Nichtmagnetische drehachse Download PDF

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Publication number
EP4258064A1
EP4258064A1 EP22167305.6A EP22167305A EP4258064A1 EP 4258064 A1 EP4258064 A1 EP 4258064A1 EP 22167305 A EP22167305 A EP 22167305A EP 4258064 A1 EP4258064 A1 EP 4258064A1
Authority
EP
European Patent Office
Prior art keywords
tungsten
weight
pivot axis
content
magnetic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP22167305.6A
Other languages
English (en)
French (fr)
Inventor
Lionel MICHELET
Jean-Claude Monachon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nivarox Far SA
Original Assignee
Nivarox Far SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nivarox Far SA filed Critical Nivarox Far SA
Priority to EP22167305.6A priority Critical patent/EP4258064A1/de
Priority to PCT/EP2023/059119 priority patent/WO2023194522A1/fr
Publication of EP4258064A1 publication Critical patent/EP4258064A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • G04B13/00—Gearwork
    • G04B13/02—Wheels; Pinions; Spindles; Pivots
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/04—Alloys based on tungsten or molybdenum
    • 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
    • G04B17/32—Component parts or constructional details, e.g. collet, stud, virole or piton
    • 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
    • G04B43/00—Protecting clockworks by shields or other means against external influences, e.g. magnetic fields
    • G04B43/007—Antimagnetic alloys
    • 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
    • G04B15/00—Escapements
    • G04B15/14—Component parts or constructional details, e.g. construction of the lever or the escape wheel

Definitions

  • the present invention relates to a part for a clock movement and in particular to a non-magnetic pivot axis for a mechanical clock movement and more particularly to a balance axis, an anchor rod and a non-magnetic escapement pinion.
  • the manufacture of a watch pivot axis consists, from a hardenable steel bar, of carrying out turning operations to define different active surfaces (span, shoulder, pivots, etc.) then subjecting the turned axis to heat treatment operations comprising at least one quench to improve the hardness of the axis and one or more tempers to improve its toughness.
  • the heat treatment operations are followed by a rolling operation of the axis pivots, an operation consisting of polishing the pivots to bring them to the required dimensions. During the rolling operation, the hardness and roughness of the pivots are further improved.
  • the pivot axes for example the balance axes, conventionally used in mechanical watch movements are made in grades of free-cutting steels which are generally carbon martensitic steels including lead and manganese sulphides to improve their machinability.
  • a steel of this type designated 20AP is typically used for these applications.
  • This type of material has the advantage of being easily machinable, in particular of being suitable for bar turning and presents, after quenching and tempering treatments, high mechanical properties which are very interesting for the production of watch pivot axes.
  • These steels have in particular high hardness after heat treatment, making it possible to obtain very good resistance to shocks.
  • the hardness of the pivots of an axle made of 20 AP steel can reach a value exceeding 700 HV after heat treatment and rolling.
  • this type of material has the disadvantage of being magnetic and of being able to disrupt the running of a watch after being subjected to a magnetic field, in particular when this material is used to produce a balance axis cooperating with a spiral balance made of ferromagnetic material. This phenomenon is well known to those skilled in the art. It should also be noted that these martensitic steels are also sensitive to corrosion.
  • austenitic stainless steels which have the particularity of being non-magnetic, that is to say of the paramagnetic or diamagnetic or antiferromagnetic type.
  • these austenitic steels have a crystallographic structure that does not allow them to be quenched and to achieve hardness and therefore impact resistance compatible with the requirements required for the production of watch pivot axes.
  • the axes obtained then present marks or severe damage in the event of shocks which will then have a negative influence on the timing of the movement.
  • One way to increase the hardness of these steels is work hardening, however this hardening operation does not make it possible to obtain hardnesses greater than 500 HV. Consequently, in the context of parts requiring pivots with high impact resistance, the use of this type of steel remains limited.
  • the object of the invention is to overcome the aforementioned drawbacks by proposing a pivot axis making it possible to limit the sensitivity to magnetic fields and to obtain mechanical properties enabling it to meet shock resistance requirements in the watchmaking field.
  • the invention relates to a pivot axis for a watch movement made at least partly in tungsten or in a tungsten alloy.
  • the tungsten alloys are alloys comprising either lanthanum oxide, copper, or nickel with the addition of one or more elements chosen from Fe, Cu, Co and Mo.
  • the oxide Lanthanum acts as a chipbreaker, which improves the machinability of the tungsten alloy.
  • Tungsten and its alloys combine high hardness with values greater than or equal to 500 HV0.5, very good corrosion resistance and very low magnetic susceptibility.
  • This material is known to be very difficult to machine, which has hampered its use in the watchmaking field to this day.
  • the term “amagnetic” material means a paramagnetic or diamagnetic or antiferromagnetic material, the magnetic permeability of which is between 0.99 and 1.01.
  • An alloy of an element is an alloy containing at least 50% by weight of said element.
  • the invention relates to a part for a watch movement and in particular to a non-magnetic pivot axis for a mechanical watch movement.
  • the invention will be described below in the context of an application to a non-magnetic balance axis 1.
  • other types of watch pivot axes are possible, such as for example watch mobile axes, typically pinions. exhaust, or even anchor rods.
  • Parts of this type have diameters at the body level preferably less than 2 mm, and pivots with a diameter less than 0.2 mm, with a precision of a few microns.
  • a balance axis 1 which comprises a plurality of sections 2 of different diameters, preferably formed by bar turning or any other machining technique by removal of chips, and conventionally defining surfaces 2a and shoulders 2b arranged between two end portions defining two pivots 3. These pivots are each intended to pivot in a bearing, typically in an orifice of a stone or a ruby.
  • At least part of the balance axis 1, namely the pivot 3, is made of a non-magnetic metallic material in order to limit advantageously its sensitivity to magnetic fields.
  • said material is pure tungsten or a tungsten alloy.
  • Pure tungsten means a material comprising tungsten in a weight percentage greater than or equal to 99.5%, preferably greater than or equal to 99.7%. It may contain possible impurities such as Mo, C, Fe and O, cited as an example.
  • Tungsten alloys are alloys comprising either lanthanum oxide, copper or nickel with the addition of one or more elements chosen from Fe, Cu, Co and Mo.
  • the alloy of tungsten with lanthanum oxide comprises the latter in a percentage by weight of between 0.2 and 5%, preferably between 0.3 and 3%, more preferably between 0.5 and 2%.
  • the alloy consists of tungsten, lanthanum oxide in a percentage by weight of between 0.2 and 5%, preferably between 0.3 and 3%, more preferably between 0.5 and 2%, and possible impurities with a total content for the latter less than or equal to 1.5% by weight.
  • the alloy of tungsten with copper comprises the latter in a percentage by weight of between 2 and 49%, preferably between 3 and 45%, more preferably between 5 and 40%.
  • the alloy consists of tungsten, copper in a percentage by weight of 2 and 49%, preferably between 3 and 45%, more preferably between 5 and 40% and possible impurities with a total content for the latter. less than or equal to 1.5% by weight.
  • the alloy of tungsten with nickel comprises the latter with a weight content of between 0.5 and 20%, preferably between 1 and 15%, more preferably between 1.5 and 10%, and comprises one or more of the chosen elements among Fe, Cu, Co and Mo with a total content for said element(s) of between 0.2 and 10%, preferably between 0.5 and 5%.
  • the alloy consists of tungsten, nickel in a percentage by weight of between 0.5 and 20%, preferably between 1 and 15%, more preferably between 1.5 and 10% and possible impurities with a total content for the latter less than or equal to 1.5% by weight.
  • Tungsten and tungsten alloys according to the invention have a hardness greater than or equal to 500 HV0.5. They have a low magnetic susceptibility with typically values lower than 8 ⁇ 10 -5 , preferably 7 ⁇ 10 -5 .
  • the balance axis 1, namely the pivot 3 is made of the aforementioned non-magnetic material 4 which is covered at least on part of its external surface with a layer 5 ensuring resistance to wear of the pivot.
  • the layer is made of Ni or NiP.
  • the phosphorus level can preferably be between 0% (we then have pure Ni) and 15% by weight.
  • the phosphorus level in the NiP can be an average level of between 6% and 9%, or a high level of between 9% and 12%. It is obvious, however, that NiP can contain a low level of phosphorus.
  • the layer when it is medium or high phosphorus NiP, it can be hardened by heat treatment.
  • the heat treatment is carried out between 200°C and 400°C for a time of between 20 minutes and 24 hours.
  • the Ni or NiP layer has a hardness preferably greater than 400 HV0.5, more preferably greater than 500 HV0.5.
  • the unhardened Ni or NiP layer has a hardness preferably greater than 500 HV0.5, but less than 600 HV0.5, that is to say preferably between 500 HV0.5 and 550 HV0.5.
  • the NiP layer can have a hardness between 900 HV0.5 and 1000 HV0.5.
  • the Ni or NiP layer can have a thickness of between 0.5 ⁇ m and 10 ⁇ m, preferably between 1 ⁇ m and 5 ⁇ m, and more preferably between 1 ⁇ m and 2 ⁇ m.
  • the layer is a layer of NiP, and more particularly a layer of chemical NiP, that is to say deposited by chemical means.
  • the pivot may comprise at least one adhesion sub-layer deposited between the non-magnetic material and the Ni or NiP layer.
  • a gold underlayer and/or a galvanic nickel underlayer may be provided under the Ni or NiP layer.
  • the Ni or NiP layer is deposited according to a process chosen from the group comprising PVD, CVD, ALD, galvanic and chemical, and preferably chemical, deposits.
  • the M(H) hysteresis curve was characterized at room temperature by varying the field applied to the samples with a vibrating sample magnetometer (VSM) of the MicroSense EZ9 type.
  • VSM vibrating sample magnetometer
  • Figure 3 represents the curve for pure tungsten.
  • the magnetic susceptibility ( ⁇ m ) is equal to 6.8 ⁇ 10 -5 . Similar values were obtained for the tungsten alloys according to the invention.
  • HV0.5 hardnesses The hardnesses measured are HV0.5 hardnesses. A value of 540 HV0.5 is obtained for the tungsten alloy with 1% by weight of carbon dioxide. lanthanum. Values in the range 500-600 HV0.5 were obtained for other tungsten alloys and pure tungsten.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • Soft Magnetic Materials (AREA)
  • Sliding-Contact Bearings (AREA)
EP22167305.6A 2022-04-08 2022-04-08 Nichtmagnetische drehachse Withdrawn EP4258064A1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP22167305.6A EP4258064A1 (de) 2022-04-08 2022-04-08 Nichtmagnetische drehachse
PCT/EP2023/059119 WO2023194522A1 (fr) 2022-04-08 2023-04-06 Axe de pivotement amagnetique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22167305.6A EP4258064A1 (de) 2022-04-08 2022-04-08 Nichtmagnetische drehachse

Publications (1)

Publication Number Publication Date
EP4258064A1 true EP4258064A1 (de) 2023-10-11

Family

ID=81307034

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22167305.6A Withdrawn EP4258064A1 (de) 2022-04-08 2022-04-08 Nichtmagnetische drehachse

Country Status (2)

Country Link
EP (1) EP4258064A1 (de)
WO (1) WO2023194522A1 (de)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH702774A4 (de) * 1974-05-22 1975-10-31
US20140198624A1 (en) * 2013-01-17 2014-07-17 Omega S.A. Part for a timepiece movement
US20200133200A1 (en) * 2018-10-24 2020-04-30 Seiko Epson Corporation Timepiece part and timepiece
CN111996430B (zh) * 2020-07-28 2021-09-28 深圳市飞亚达精密科技有限公司 一种不受磁场影响的钨铜合金及其制造方法和用途
EP3940112A1 (de) * 2020-07-16 2022-01-19 Richemont International Sa Verfahren zu verbesserung eines materials für uhrwerke

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH702774A4 (de) * 1974-05-22 1975-10-31
US20140198624A1 (en) * 2013-01-17 2014-07-17 Omega S.A. Part for a timepiece movement
US20200133200A1 (en) * 2018-10-24 2020-04-30 Seiko Epson Corporation Timepiece part and timepiece
EP3940112A1 (de) * 2020-07-16 2022-01-19 Richemont International Sa Verfahren zu verbesserung eines materials für uhrwerke
CN111996430B (zh) * 2020-07-28 2021-09-28 深圳市飞亚达精密科技有限公司 一种不受磁场影响的钨铜合金及其制造方法和用途

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
"Wolfram Werkstoffeigenschaften und Anwendungen", 2 September 2000 (2000-09-02), XP055016931, Retrieved from the Internet <URL:http://www.plansee.com/lib/Tungsten.pdf> [retrieved on 20120119] *
PLANSEE: "Tungsten", 20 March 2012 (2012-03-20), Plansee, XP055022737, Retrieved from the Internet <URL:www.plansee.com> [retrieved on 20120323] *
PLANSEE: "Tungsten-based composites", 20 January 2022 (2022-01-20), XP055964036, Retrieved from the Internet <URL:https://web.archive.org/web/20220120033022/https://www.plansee.com/en/materials/w-mmc.html> [retrieved on 20220922] *

Also Published As

Publication number Publication date
WO2023194522A1 (fr) 2023-10-12

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