EP3828642A1 - Spiralfeder für uhrwerk und herstellungsverfahren dafür - Google Patents

Spiralfeder für uhrwerk und herstellungsverfahren dafür Download PDF

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Publication number
EP3828642A1
EP3828642A1 EP19212457.6A EP19212457A EP3828642A1 EP 3828642 A1 EP3828642 A1 EP 3828642A1 EP 19212457 A EP19212457 A EP 19212457A EP 3828642 A1 EP3828642 A1 EP 3828642A1
Authority
EP
European Patent Office
Prior art keywords
layer
weight
manufacturing process
spiral spring
process according
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Withdrawn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
EP19212457.6A
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English (en)
French (fr)
Inventor
Lionel MICHELET
M. Christian CHARBON
M. Marco VERARDO
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
Nivarox SA
Original Assignee
Nivarox Far SA
Nivarox 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, Nivarox SA filed Critical Nivarox Far SA
Priority to EP19212457.6A priority Critical patent/EP3828642A1/de
Priority to EP20811381.1A priority patent/EP4066066A1/de
Priority to JP2022531415A priority patent/JP7475447B2/ja
Priority to CN202080082129.5A priority patent/CN114730155A/zh
Priority to US17/779,659 priority patent/US20220413438A1/en
Priority to PCT/EP2020/083622 priority patent/WO2021105352A1/fr
Publication of EP3828642A1 publication Critical patent/EP3828642A1/de
Withdrawn legal-status Critical Current

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    • GPHYSICS
    • G04HOROLOGY
    • G04BMECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B17/00Mechanisms for stabilising frequency
    • G04B17/04Oscillators acting by spring tension
    • G04B17/06Oscillators with hairsprings, e.g. balance
    • G04B17/066Manufacture of the spiral spring

Definitions

  • the invention relates to a method of manufacturing a spiral spring intended to equip a balance of a timepiece movement and the spiral spring resulting from the method.
  • spiral springs are also centered on the concern for thermal compensation, so as to guarantee regular chronometric performance. This requires obtaining a thermoelastic coefficient close to zero. We are also looking to produce spiral springs exhibiting limited sensitivity to magnetic fields.
  • New balance springs have been developed from alloys of niobium and titanium.
  • these alloys pose problems of sticking and seizing in the drawing or drawing dies and against the rolling rolls, which makes them almost impossible to transform into fine wires by the standard processes used for example for steel. .
  • This copper layer on the wire has a disadvantage. It does not allow fine control of the wire geometry during wire calibration and rolling. These dimensional variations of the Nb-Ti core of the wire result in significant variations in the torques of the balance springs.
  • the present invention provides a method of manufacturing a spiral spring which makes it possible to facilitate shaping by deformation while avoiding the drawbacks associated with copper.
  • the method of manufacturing the spiral spring according to the invention comprises a heat treatment step aimed at transforming part of the Cu layer coating the core in Nb-Ti into a layer of intermetallics Cu, Ti and remove the remaining Cu layer.
  • This intermetallic layer then forms the outer layer which is in contact with the dies and the rolling rolls. It is chemically inert and ductile and makes it easy to draw and roll the spiral wire. It has the other advantage of facilitating the separation between the hairsprings after the fixing step following the stretching.
  • the intermetallic layer is retained on the hairspring at the end of the manufacturing process. It is sufficiently thin with a thickness of between 20 nm and 10 microns, preferably between 300 nm and 1.5 ⁇ m, so as not to significantly modify the thermoelastic coefficient (CTE) of the hairspring. It is also perfectly adherent to the Nb-Ti core.
  • CTE thermoelastic coefficient
  • the invention is more specifically described for a Cu layer partially transformed into a Cu, Ti intermetallic layer.
  • the present invention is applicable for other elements such as Sn, Fe, Pt, Pd, Rh, Al, Au, Ni, Ag, Co and Cr also capable of forming intermetallics with Ti. It is also applicable for an alloy of one of these elements.
  • the invention relates to a method of manufacturing a spiral spring intended to equip a balance of a timepiece movement.
  • This spiral spring is made of a binary type alloy comprising niobium and titanium. It also relates to the spiral spring resulting from this process.
  • the blank of step a) comprises a layer around the Nb-Ti core of a material X chosen from Cu, Sn, Fe, Pt, Pd, Rh, Al , Au, Ni, Ag, Co and Cr or an alloy of these elements.
  • a material X chosen from Cu, Sn, Fe, Pt, Pd, Rh, Al , Au, Ni, Ag, Co and Cr or an alloy of these elements.
  • it can be Cu, Cu-Sn, Cu-Ni, etc.
  • the method comprises a step of supplying said material X around the core in Nb-Ti to form the layer in X, said step being carried out between step a) and step c) of deformation .
  • the manufacturing process also includes a heat treatment step to partially transform the X-shaped layer into an X, Ti intermetallic layer around the Nb-Ti core.
  • the heat treatment is carried out at a temperature between 200 and 900 ° C for 15 minutes to 100 hours.
  • the blank thus successively comprises the core in Nb-Ti, the layer of intermetallic X, Ti and the remaining part of the layer in X, said step being carried out between step b) and step c) or between two sequences of the deformation step c).
  • the manufacturing process then comprises a step of removing the remaining part of the layer in X. This step is carried out between step b) and step c), between two sequences of the deformation step c) or between step c) and step d).
  • the core is made from an Nb-Ti alloy comprising between 5 and 95% by weight of titanium.
  • the alloy used in the present invention comprises by weight between 40 and 60% titanium.
  • it comprises between 40% and 49% by weight of titanium, and more preferably between 46% and 48% by weight of titanium.
  • the percentage of titanium is sufficient to obtain a maximum proportion of Ti precipitates in the form of alpha phase while being reduced to avoid the formation of a martensitic phase causing problems of fragility of the alloy during its use.
  • the Nb-Ti alloy used in the present invention does not comprise other elements except for possible and inevitable traces. This makes it possible to avoid the formation of fragile phases.
  • the oxygen content is less than or equal to 0.10% by weight of the total, or even less than or equal to 0.085% by weight of the total.
  • the tantalum content is less than or equal to 0.10% by weight of the total.
  • the carbon content is less than or equal to 0.04% by weight of the total, in particular less than or equal to 0.020% by weight of the total, or even less than or equal to 0.0175% by weight of the total.
  • the iron content is less than or equal to 0.03% by weight of the total, in particular less than or equal to 0.025% by weight of the total, or even less than or equal to 0.020% by weight of the total.
  • the nitrogen content is less than or equal to 0.02% by weight of the total, in particular less than or equal to 0.015% by weight of the total, or even less than or equal to 0.0075% by weight of the total.
  • the hydrogen content is less than or equal to 0.01% by weight of the total, in particular less than or equal to 0.0035% by weight of the total, or even less than or equal to 0.0005% by weight of the total.
  • the silicon content is less than or equal to 0.01% by weight of the total.
  • the nickel content is less than or equal to 0.01% by weight of the total, in particular less than or equal to 0.16% by weight of the total.
  • the content of ductile material, such as copper, in the alloy is less than or equal to 0.01% by weight of the total, in particular less than or equal to 0.005% by weight of the total.
  • the aluminum content is less than or equal to 0.01% by weight of the total.
  • the Nb-Ti core of the blank in step a) is coated with a layer of material X as listed above.
  • the addition of the X-shaped layer around the core can be achieved by galvanic means, by PVD, CVD or by mechanical means.
  • a tube of material X is fitted to a bar of the Nb-Ti alloy.
  • the assembly is deformed by hammering, stretching and / or wire drawing to thin the bar and form the blank made available in step a).
  • the present invention does not exclude providing the X-shaped layer during the method of manufacturing the spiral spring between step a) and step c) of deformation.
  • the thickness of the layer in X is chosen so that the ratio of material surface X / surface area of the Nb-Ti core for a given wire section is less than 1, preferably less than 0.5, and more preferably included between 0.01 and 0.4.
  • the thickness is preferably between 1 and 500 micrometers for a wire having a total diameter of 0.2 to 1 millimeter.
  • the beta-type quenching in step b) is a dissolving treatment. Preferably, it is carried out for a period of between 5 minutes and 2 hours at a temperature of between 700 ° C and 1000 ° C, under vacuum, followed by cooling under gas. More particularly, this beta quench is a dissolving treatment at 800 ° C. under vacuum for 5 minutes to 1 hour, followed by cooling under gas.
  • Deformation step c) is carried out in several sequences.
  • deformation is meant a deformation by wire drawing and / or rolling.
  • the deformation step comprises at least successively a first wire drawing sequence, a second calibration wire drawing sequence and a third rolling sequence, preferably with a rectangular profile compatible with the entry section of a stepping spindle. .
  • Each sequence is carried out with a given strain rate between 1 and 5, this strain rate corresponding to the classic formula 2ln (d0 / d), where d0 is the diameter of the last beta hardening, and where d is the diameter of the strain-hardened wire.
  • the global accumulation of deformations over the whole of this succession of sequences leads to a total rate of deformation between 1 and 14.
  • the manufacturing process comprises the step of heat treatment to partially transform the X-shaped layer into an X, Ti intermetallic layer around the Nb-Ti core.
  • This step is carried out for 15 minutes to 100 hours at a temperature between 200 and 900 ° C. Preferably, it is carried out for 5 to 20 hours between 400 and 500 ° C.
  • This heat treatment step can be used to precipitate the titanium in the alpha phase.
  • the layer of intermetallic has a thickness of between 20 nm and 10 ⁇ m, preferably between 300 nm and 1.5 ⁇ m, more preferably between 400 and 800 nm.
  • the remaining layer of X has a thickness between 1 and 25 ⁇ m.
  • the intermetallic layer comprises, for example, CU 4 Ti, Cu 2 Ti, CuTi, Cu 3 Ti 2 and CuTi 2 .
  • the microscopy at figure 1 shows the structure of the blank after heat treatment at 450 ° C of a niobium-titanium alloy with 47% by weight of titanium covered with a layer of copper.
  • the NbTi core 47 is successively observed, the Cu, Ti intermetallic layer having a thickness of the order of 700 nm and the remaining copper layer having a thickness of the order of 5 ⁇ m.
  • the figure 3 represents the XRD spectrum for this same alloy of the spiral spring according to the invention after removal of the Cu layer and after the slitting and fixing steps.
  • the XRD spectrum for this same alloy with the copper layer but in the absence of the heat treatment is shown on figure 2 .
  • This heat treatment aimed at forming intermetallics can be carried out before the deformation step c) or between two deformation sequences during step c).
  • it is carried out in step c) between the first wire drawing sequence and the second calibration wire drawing sequence.
  • the remaining X-layer is removed so as to have the intermetallic layer as the outer layer.
  • This step can be carried out by chemical attack in a solution based on cyanides or acids, for example nitric acid. It will be specified that the present invention does not exclude that certain intermetallics are also dissolved in the acid. This is for example the case with Cu 4 Ti in a nitric acid solution.
  • the X-layer can be removed at different times in the process depending on the desired effect. Preferably, it is removed in step c) before the calibration wire drawing so as to very finely control the dimensions. ends of the spiral wire.
  • the intermetallics present in the outer layer then prevent the sticking of the wire in the dies, against the rolling rolls and between the spirals during fixing. More preferably, it is removed between the first wire drawing sequence and the second calibration wire drawing sequence. According to a less advantageous variant, it is removed after the calibration wire drawing before the rolling, so as to prevent the wire sticking against the rolling rolls and between the spirals during fixing. According to a variant which is also less advantageous, it is removed at the end of the deformation step c) before the scaling step. In this case, the outer layer of intermetallics only makes it possible to avoid the sticking between the balance springs during fixing.
  • step e) of final heat treatment on the spiral spring is followed by step e) of final heat treatment on the spiral spring.
  • This final heat treatment is a precipitation treatment of Ti in the alpha phase lasting between 1 and 80 hours, preferably between 5 and 30 hours, at a temperature between 350 and 700 ° C, preferably between 400 and 600. ° C.
  • the process may include intermediate heat treatments between the deformation sequences in this same range of times and temperatures.
  • the spiral spring produced according to this process has an elastic limit greater than or equal to 500 MPa, preferably greater than 600 MPa, and more precisely between 500 and 1000 MPa.
  • it has a modulus of elasticity less than or equal to 120 GPa, and preferably less than or equal to 100 GPa.
  • the spiral spring comprises an Nb-Ti core coated with a layer of intermetallics X, Ti with X chosen from Cu, Sn, Fe, Pt, Pd, Rh, Al, Au, Ni, Ag, Co and Cr or an alloy of one of these elements, said intermetallic layer having a thickness between 20 nm and 10 ⁇ m, of preferably between 300 nm and 1.5 ⁇ m, more preferably between 400 nm and 800 nm.
  • the intermetallic layer is a Cu, Ti layer.
  • the spiral spring core has a two-phase microstructure comprising niobium in the beta phase and titanium in the alpha phase.
  • the spiral spring produced according to the invention has a thermoelastic coefficient, also called CTE, allowing it to guarantee the maintenance of chronometric performance despite the variation in the temperatures of use of a watch incorporating such a spiral spring.
  • the method of the invention allows the production, and more particularly the shaping, of a balance spring for a balance made of a niobium-titanium type alloy, typically containing 47% by weight of titanium (40-60%).
  • This alloy has high mechanical properties, by combining a very high elastic limit, greater than 600 MPa, and a very low modulus of elasticity, of the order of 60 Gpa to 80 GPa. This combination of properties is well suited for a spiral spring.
  • such an alloy is paramagnetic.
EP19212457.6A 2019-11-29 2019-11-29 Spiralfeder für uhrwerk und herstellungsverfahren dafür Withdrawn EP3828642A1 (de)

Priority Applications (6)

Application Number Priority Date Filing Date Title
EP19212457.6A EP3828642A1 (de) 2019-11-29 2019-11-29 Spiralfeder für uhrwerk und herstellungsverfahren dafür
EP20811381.1A EP4066066A1 (de) 2019-11-29 2020-11-27 Spiralfeder für uhrwerk und verfahren zu ihrer herstellung
JP2022531415A JP7475447B2 (ja) 2019-11-29 2020-11-27 時計ムーブメント用ゼンマイおよびその製造方法
CN202080082129.5A CN114730155A (zh) 2019-11-29 2020-11-27 用于钟表机芯的螺旋弹簧及其制造方法
US17/779,659 US20220413438A1 (en) 2019-11-29 2020-11-27 Spiral spring for a horological movement and manufacturing method thereof
PCT/EP2020/083622 WO2021105352A1 (fr) 2019-11-29 2020-11-27 Ressort spiral pour mouvement d'horlogerie et son procede de fabrication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19212457.6A EP3828642A1 (de) 2019-11-29 2019-11-29 Spiralfeder für uhrwerk und herstellungsverfahren dafür

Publications (1)

Publication Number Publication Date
EP3828642A1 true EP3828642A1 (de) 2021-06-02

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Application Number Title Priority Date Filing Date
EP19212457.6A Withdrawn EP3828642A1 (de) 2019-11-29 2019-11-29 Spiralfeder für uhrwerk und herstellungsverfahren dafür
EP20811381.1A Pending EP4066066A1 (de) 2019-11-29 2020-11-27 Spiralfeder für uhrwerk und verfahren zu ihrer herstellung

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP20811381.1A Pending EP4066066A1 (de) 2019-11-29 2020-11-27 Spiralfeder für uhrwerk und verfahren zu ihrer herstellung

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US (1) US20220413438A1 (de)
EP (2) EP3828642A1 (de)
JP (1) JP7475447B2 (de)
CN (1) CN114730155A (de)
WO (1) WO2021105352A1 (de)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3502289A1 (de) * 2017-12-21 2019-06-26 Nivarox-FAR S.A. Spiralfeder für uhrwerk, und ihr herstellungsverfahren
EP3502288A1 (de) * 2017-12-21 2019-06-26 Nivarox-FAR S.A. Herstellungsverfahren einer spiralfeder für uhrwerk

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3502289A1 (de) * 2017-12-21 2019-06-26 Nivarox-FAR S.A. Spiralfeder für uhrwerk, und ihr herstellungsverfahren
EP3502288A1 (de) * 2017-12-21 2019-06-26 Nivarox-FAR S.A. Herstellungsverfahren einer spiralfeder für uhrwerk

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
MARTIN N WILSON: "Advances in low-loss Nb-Ti strand cable", 1 January 2009 (2009-01-01), pages 8 - 12, XP009139537, ISBN: 978-92-9083-325-3, Retrieved from the Internet <URL:http://cdsweb.cern.ch/record/1163708/files/p8.pdf> *
WARNES W H ET AL: "Critical current distributions in superconducting composites", CRYOGENICS, ELSEVIER, KIDLINGTON, GB, vol. 26, no. 12, 1 December 1986 (1986-12-01), pages 643 - 653, XP024048697, ISSN: 0011-2275, [retrieved on 19861201], DOI: 10.1016/0011-2275(86)90162-1 *

Also Published As

Publication number Publication date
JP7475447B2 (ja) 2024-04-26
JP2023504079A (ja) 2023-02-01
EP4066066A1 (de) 2022-10-05
CN114730155A (zh) 2022-07-08
WO2021105352A1 (fr) 2021-06-03
US20220413438A1 (en) 2022-12-29

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