Flexible timepiece component for an oscillator mechanism and timepiece movement comprising such a component

Abstract

The present invention relates to a flexible watch component for an oscillator mechanism in a watch movement, the component extending along a main plane (P) and comprising at least a portion made of a composite material (1), the composite material (1) comprising a matrix (2) and a plurality of nanotubes or nanowires (3) distributed in the matrix (2), the nanotubes or nanowires (3) being juxtaposed and arranged substantially parallel to an axis (A) substantially perpendicular to the plane (P) of the component, the matrix comprising a flexible filler material (4) to fill the gaps between the nanotubes or nanowires (3), the filler material (4) comprising at least partially a thermal compensation material, wherein the thermoelastic coefficient (TEC) is opposite in sign to the thermoelastic coefficient of the other materials of the composite material (1).

Description

Technical Field

[0001] This invention relates to flexible watch components, particularly for oscillator mechanisms in watch movements having a positive thermoelastic coefficient.

[0002] The present invention also relates to a watch movement including this component. Background Technology

[0003] A watch movement typically includes a mainspring barrel, an escapement, and a mechanical oscillator mechanism. The escapement specifically includes the escape fork assembly and the escape wheel, while the oscillator mechanism includes a spiral hairspring associated with an oscillating inertial block known as the balance wheel.

[0004] Technological advancements in composite materials now enable the manufacture of certain components from innovative and high-performance materials, at least in part, without the use of metals. Currently, attempts are being made to manufacture components using, for example, nanotubes or nanowires. Materials containing nanotubes or nanowires offer advantages in terms of lightweight and strength. Therefore, document JP2008116205A describes a helical filament comprising a graphite and amorphous carbon matrix reinforced with carbon nanotubes, the carbon nanotubes being dispersed in the matrix and aligned along the longitudinal direction of the helix.

[0005] However, flexible components (such as resonators) are typically subject to deformation and changes in their elastic properties due to temperature variations during their repeated movements. In the case of a balance wheel with a hairspring, the frequency variation as a function of temperature generally follows the formula: in: - The frequency change is a function of temperature; - The change in Young's modulus as a function of temperature is the thermoelastic coefficient (TEC) of the balance spring. - For ppm•℃ -1 This represents the coefficient of thermal expansion of the balance wheel and hairspring; - For ppm•℃ -1 The value represents the coefficient of expansion of the balance wheel.

[0006] Deformation and changes in material properties cause variations in the elastic modulus of flexible components. However, these temperature-induced changes in elastic modulus hinder the accuracy of watch movements. Summary of the Invention

[0007] Therefore, the objective of this invention is to provide a flexible watch component that avoids the aforementioned problems.

[0008] For this purpose, the present invention relates to a flexible watch component for an oscillator mechanism in a watch movement, the component extending along a main plane and including at least a portion made of a composite material.

[0009] The unusual feature of the component is that the composite material comprises a matrix and multiple nanotubes or nanowires distributed in the matrix, the nanotubes or nanowires being juxtaposed and arranged to be substantially parallel to an axis substantially perpendicular to the plane of the component, the matrix comprising a flexible filler material to fill the gaps between the nanotubes or nanowires, the filler material comprising at least a portion of a thermal compensation material, wherein the thermoelastic coefficient is opposite in sign to the thermoelastic coefficient of the other materials in the composite material.

[0010] Therefore, this flexible component can compensate for changes in the properties of materials used, such as those in a spiral hairspring, due to temperature variations. In fact, the thermal compensation material has a thermoelastic modulus of opposite sign to that of the other materials in the composite material; the change in the elastic modulus of the compensation material occurs inversely to the deformation of the other materials in the component (which also have thermoelastic components of opposite sign). Therefore, the performance of the component remains largely the same regardless of the temperature at which it is used (especially under conditions of significant temperature changes).

[0011] According to an advantageous embodiment, the thermal compensation material has a thermoelastic coefficient greater than 0. In this case, the thermal compensation material compensates for other materials with a thermoelastic coefficient less than zero.

[0012] According to an advantageous embodiment, the thermal compensation material preferably mainly comprises silicon dioxide (SiO2), or even entirely comprises silicon dioxide (SiO2).

[0013] According to a preferred embodiment, the thermal compensation material preferably comprises mainly niobium, or even entirely niobium.

[0014] According to an advantageous embodiment, the thermal compensation material forms the outer layer of the matrix, and the outer layer preferably completely surrounds the matrix.

[0015] According to the preferred implementation scheme, the thermal compensation material is directly arranged on nanotubes or nanowires.

[0016] According to a preferred embodiment, nanotubes are made of carbon.

[0017] According to the preferred implementation scheme, the nanotubes are multi-walled.

[0018] According to an advantageous embodiment, the nanowires are prepared using elements selected from the following list: gold, silicon, silicon oxide, boron nitride, gallium nitride, silicon nitride, zinc oxide, gallium arsenide, tungsten sulfide, silver, copper, manganese arsenide, and indium arsenide.

[0019] According to an advantageous embodiment, the nanotube or nanowire has a diameter in the range of 2 to 50 nm (preferably in the range of 3 to 15 nm or 5 to 10 nm).

[0020] According to an advantageous embodiment, the nanotubes or nanowires have a length in the range of 100 to 500 micrometers (preferably in the range of 100 to 300 micrometers or 150 to 200 micrometers).

[0021] According to an advantageous embodiment, the filler material further comprises elements selected from the following list: silicon, tungsten, organic materials (such as parylene), hexagonal boron nitride, Al2O3 type single crystal ruby, diamond, tungsten disulfide or molybdenum disulfide, graphite, lead, silicon carbide, nickel, indium phosphide, and titanium oxide.

[0022] According to an advantageous embodiment, the component is a spiral hairspring of an oscillator mechanism or a flexible blade guide plate of an oscillator mechanism.

[0023] The present invention also relates to a watch movement comprising a flexible watch component according to the present invention. Attached Figure Description

[0024] Further features and advantages of the invention will become apparent when reading, with reference to the accompanying drawings, several embodiments given by way of non-limiting example only, in which: Figure 1 A perspective view schematically illustrating a composite material according to a first embodiment of the present invention is shown. Figure 2 A perspective view schematically illustrating a composite material according to a second embodiment of the present invention is shown. Figure 3 A schematic perspective view of a balance wheel equipped with a spiral hairspring and an oscillating mechanism, and Figure 4 A schematic cross-sectional view of the composite material during a method for manufacturing a first embodiment of the invention is shown. Detailed Implementation

[0025] In this specification, we describe a flexible component used in a watch movement. This component is selected from a list of flexible components, including, for example, the oscillator mechanism spiral hairspring or the flexible oscillator mechanism blade guide plate.

[0026] The flexible component is preferably flat and extends along the main plane (P). The component comprises... Figure 1 At least a portion is made of the composite material 1 indicated in the diagram. Preferably, the component is entirely made of this composite material 1. Therefore, components from the aforementioned list can be made of this composite material 1.

[0027] The composite material 1 comprises a matrix 2 and a plurality of nanotubes or nanowires 3 distributed in the matrix 2. The component has a substantially flat shape, for example, extending along a preferred plane P.

[0028] Nanotubes or nanowires 3 form the structure of composite material 1, wherein they are juxtaposed and arranged to be substantially parallel to each other. The term nanotube refers to a tube in which the inner side is typically hollow, while nanowires are typically solid (i.e., monolithic).

[0029] Nanotubes or nanowires 3 are arranged substantially parallel to axis A, which is perpendicular to plane P of component 1. They are uniformly distributed to be homogeneously spaced apart in the matrix 2. Advantageously, the composite material is realized such that nanotubes or nanowires 3 appear throughout the entire mass of the matrix 2.

[0030] The nanotube or nanowire 3 has a diameter D, for example, in the range of 2 to 50 nm. Preferably, the nanotube or nanowire 3 has a diameter in the range of 3 to 15 nm or 5 to 10 nm.

[0031] The nanotube or nanowire 3 may have a length L in the range of 100 to 500 micrometers. Preferably, the nanotube or nanowire 3 has a length in the range of 100 to 300 micrometers or 150 to 200 micrometers.

[0032] In a first embodiment, the composite material comprises carbon nanotubes 3. The carbon nanotubes 3 are typically multi-walled, but may optionally be single-walled.

[0033] In the second embodiment, the composite material comprises nanowires 3 prepared using at least a portion of the following: gold, silicon, boron nitride, gallium nitride, silicon nitride, zinc oxide, gallium arsenide, tungsten sulfide, silver, copper, manganese arsenide, and indium arsenide.

[0034] The matrix 2 contains a filler material 4 to fill the gaps and bond the nanotubes or nanowires 3 together. The material 4 can advantageously contain the nanotubes or nanowires 3 by being injected into the gaps 5 between them. This material 4 helps to provide cohesive forces between the nanotubes or nanowires 3 and thus alters all the mechanical properties of the nanotubes or nanowires 3, particularly making the matrix flexible. In a first embodiment of the nanotubes, the material 4 may also be disposed on the inner side 14 of the nanotubes 3.

[0035] The filler material 4 enables the flexibility of the component, and the filler material 4 possesses elastic mechanical properties. Furthermore, the flexible component is achieved due to the geometry selected for the component. Therefore, thanks to this flexible filler material 4, specific components of a watch mechanism can be realized.

[0036] According to the present invention, the filler material 4 includes at least a heat compensation material 18 in which the thermoelastic coefficient (TEC) is opposite to that of other materials of the composite material (1).

[0037] The thermoelastic coefficient (TEC) is, for example, in the range of 1 ppm / ℃ to 100 ppm / ℃.

[0038] The volume fraction and thermoelastic coefficient of the thermal compensation material 18 are selected to be the same as those of the compensation filler material 4. This selection can be made by calculation or experience.

[0039] In a first alternative embodiment, the thermal compensation material 18 preferably comprises primarily silicon oxide (SiO2), or even entirely silicon oxide. Silicon oxide can be obtained by oxidizing silicon. Silicon is deposited in a thin layer using known LPCVD-type low-pressure vapor deposition techniques, or via ALD-type atomic layer deposition, PECVD-type plasma deposition, or practically via epitaxial directional growth. In this case, the thermal compensation material 18 has a thermoelastic modulus greater than zero, and thus can compensate for materials with a thermoelastic modulus less than zero.

[0040] In a second alternative embodiment, the thermal compensation material 18 preferably comprises primarily niobium, or even entirely niobium. Niobium is a transition metal that can be deposited using conventional, known thin-film deposition techniques such as PVD, CVD, or ALD.

[0041] For both embodiments, the filler material 4 forming the substrate 2 may further include additional elements from the following list: tungsten, organic materials such as parylene, hexagonal boron nitride, Al2O3 type single crystal ruby, diamond, tungsten disulfide or molybdenum disulfide, graphite, lead, silicon carbide, nickel, indium phosphide, titanium oxide, or carbon. For example, the filler material may be silicon, and the thermal compensation layer may be silicon oxide.

[0042] exist Figure 1 In the first embodiment shown, the thermal compensation material 18 is directly disposed on the nanotubes or nanowires 3. The thermal compensation material 18 permeates between the nanotubes or nanowires 3 to at least partially cover the nanotubes or nanowires. If a filler material is present, elements of the filler material 4 also permeate between the nanotubes or nanowires 3 to cover the thermal compensation material 18. In this case, the compensation material 1 is formed by the nanotubes or nanowires 3, the thermal compensation material 18, and additional elements of the filler material 4.

[0043] In the case of niobium, the latter can be mixed with elements of filler material 4 (e.g., titanium) to form an alloy that provides thermal compensation properties according to the invention.

[0044] In a first alternative embodiment, the elements of the filler material 4 permeate between the nanotubes or nanowires 3 and are then covered by a thermal compensation material. The thermal compensation material also permeates between the nanotubes or nanowires, but does not directly contact the nanotubes or nanowires.

[0045] In a second alternative embodiment, only the thermal compensation material 18 permeates between the nanotubes or nanowires to bond them together and form a component. In this case, the filler material 4 is formed solely of the thermal compensation material without any additional elements. The composite material 1 is then formed from the nanotubes or nanowires 3 and the thermal compensation material 18.

[0046] In a second embodiment, the compensating material 18 forms an outer layer 19 of the substrate, which preferably completely surrounds the substrate, although the layer may be deposited only on some surfaces. In this embodiment, the elements of the filler material 4 permeate between the nanotubes or nanowires 3 to form the core of the component, and then the thermal compensating material layer 19 is deposited around the core to form the component.

[0047] The filler material 4 enables the flexibility of the component; material 4 possesses flexible mechanical properties that allow the component to deform elastically. Furthermore, the flexible component is achieved through the geometry chosen for it. The component is, for example, the spiral hairspring 6 of the oscillator mechanism 8 in a watch movement.

[0048] Therefore, watch components can benefit from the advantages of composite materials based on nanotubes or nanowires, while retaining the basic characteristics of this type of component (e.g., for use in spiral hairsprings).

[0049] Figure 3 This indicates the spiral hairspring 6 of the balance wheel 8, which is made from this flexible composite material. The spiral hairspring 6 is a narrow strip wound in an Archimedean spiral, resulting in gaps between the facing portions of the strip. Therefore, the desired hairspring effect is achieved by contracting and deforming the spiral. The balance wheel 8 includes a ring 9 and two straight arms 11, 21 that intersect at the center of the ring 9 and connect opposite sides of the ring 9. Arms 11, 21 support a shaft 12 substantially perpendicular to the plane of the ring 9. The shaft 12 supports the spiral hairspring 6 in a plane parallel to the plane of the ring 9 via a first end. The second end is intended to be attached to another part 17 of the watch movement.

[0050] To manufacture the component, a method including, for example, the following steps is used: - First step: Preferably, a substrate (e.g., a silicon substrate) is prepared by photolithography, such that the growth of nanotubes or nanowire clusters occurs at specific locations corresponding to the shape of the desired component. Thus, flexible spiral or pivot shapes are designed by photolithography.

[0051] - Second step: Growing nanotubes or nanowires on a substrate (not shown in the attached diagram). - Third step: Inserting the matrix's constituent filler material into the nanotube or nanowire distribution, and - Step 4: Separate the component from the substrate.

[0052] During the second step, nanotubes or nanowires 12 are grown parallel to an axis that is substantially perpendicular to the substrate.

[0053] For carbon nanotubes, examples of the first and second steps can be found in Richard Scott Hansen’s paper “Mechanical and electrical properties of carbon-nanotube-templated metallic microstructures” (June 2012) or Collin Brown’s dissertation at Brigham Young University entitled “Infiltration of CNT forests by Atomic Layer Deposition for MEMS applications” (April 22, 2014).

[0054] exist Figure 4 In this process, substrate 9 is coated with a silica layer 10 and a catalyst layer 11 (e.g., iron). Carbon nanotubes 12 are formed on the catalyst layer 11 by growth.

[0055] Upstream of the second step, additional nanotubes can be mixed in a solvent and dispersed, for example, on a catalyst layer by ultrasonication to define a top layer of nanotubes. This top layer 13 of the nanotubes is porous, allowing carbon (or other materials) forming the nanotubes 12 to be deposited therethrough, so that the nanotubes 12 grow beneath the top layer 13. This ensures the regular and homogeneous growth of the nanotubes 12, resulting in them all having substantially the same length. Due to the porosity of this top layer, the third step is also performed through the top layer 13 of the nanotubes 12.

[0056] Regarding the fabrication of the nanowires, conventional techniques associated with the materials selected in the list are used. Thin-layer deposition is preferably used, such as chemical deposition via CVD (chemical vapor deposition) or physical deposition via PVD (physical vapor deposition). As in the first embodiment, a photolithography method is used to select the location of a substrate (e.g., made of silicon) where the nanowires are grown. A flexible material is inserted between the nanowires. Finally, once completed, the component is separated from the substrate.

[0057] International patent application WO 2014 / 172660 provides an example embodiment of silica nanowires. Silica nanowires have a thermoelastic coefficient greater than zero. Therefore, the thermoelastic compensation material of the filler must have a thermoelastic coefficient less than zero to compensate for the material of the nanowires.

[0058] Naturally, the present invention is not limited to the embodiments described with reference to the accompanying drawings, and alternative embodiments may be contemplated without departing from the scope of the invention.

Claims

1. A flexible watch component (6, 7) for an oscillator mechanism in a watch movement, said component extending along a main plane (P) and comprising at least a portion made of a composite material (1), characterized in that, The composite material (1) comprises a matrix (2) and a plurality of nanowires (3) distributed in the matrix (2). The nanowires (3) are juxtaposed and arranged substantially parallel to an axis (A) substantially perpendicular to the plane (P) of the component. The matrix comprises a flexible filler material (4) to fill the gaps between the nanowires (3). The filler material (4) comprises at least a portion of a thermal compensation material (18), wherein the thermoelastic coefficient (TEC) is opposite in sign to the thermoelastic coefficient of the other materials of the composite material (1). The thermal compensation material preferably comprises mainly niobium, or even entirely niobium. The nanowires (3) are prepared using elements selected from the following list: gold, silicon, silicon oxide, boron nitride, gallium nitride, silicon nitride, zinc oxide, gallium arsenide, tungsten sulfide, silver, copper, manganese arsenide, and indium arsenide.

2. The components (6, 7) as described in claim 1, characterized in that, The thermal compensation material (18) has a thermoelastic coefficient greater than 0.

3. The components (6, 7) as described in claim 2, characterized in that, The thermal compensation material (18) preferably mainly comprises silicon oxide (SiO2), or even entirely comprises silicon oxide (SiO2).

4. The components (6, 7) as described in claim 2, characterized in that, The heat compensation material preferably mainly contains niobium, or even completely contains niobium.

5. The component (6, 7) as described in any of the preceding claims, characterized in that, The thermal compensation material forms the outer layer of the substrate.

6. The component (6, 7) as described in any one of the preceding claims, characterized in that, The thermal compensation material is directly arranged on the nanowires.

7. The component (6, 7) as described in any of the preceding claims, characterized in that, The nanowire (3) has a diameter (D) in the range of 3 to 15 nm or 5 to 10 nm.

8. The component (6, 7) as described in any of the preceding claims, characterized in that, The nanowire (3) has a length (L) in the range of 100 to 500 micrometers, preferably in the range of 100 to 300 micrometers or 150 to 200 micrometers.

9. The component (6, 7) as described in any of the preceding claims, characterized in that, The filler material (4) further includes elements selected from the following list: silicon, tungsten, organic materials such as parylene, hexagonal boron nitride, Al2O3 type single crystal ruby, diamond, tungsten disulfide or molybdenum disulfide, graphite, lead, silicon carbide, nickel, indium phosphide, titanium oxide, and silicon.

10. The component (6, 7) as described in any one of the preceding claims, characterized in that, The component is a spiral hairspring (6) of an oscillator mechanism or a flexible blade guide plate of an oscillator mechanism.

11. A watch movement, characterized in that, The watch movement includes a flexible watch component (6, 7) according to any one of the preceding claims.

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