Method for producing timepiece assembly and timepiece assembly

Abstract

A method of producing a timepiece assembly (3) comprising a first timepiece part (1) and at least one second timepiece part (2) different from the first timepiece part (1), the first timepiece part (1) comprising a connecting portion comprising at least one opening (10), the second timepiece part (2) comprising at least one formation (20), said connecting portion of said first timepiece part (1) and / or said configuration of said second timepiece part (2) forms a sintered zirconia-based portion, said method comprising a heat treatment step of joining together, said heat treatment being intended to cause a phase change of said sintered zirconia-based portion from a tetragonal phase to a monoclinic phase or vice versa, the phase change causes a dimensional change of at least the sintered zirconia-based portion in order to join together the connection portion of the first timepiece part (1) and the configuration of the second timepiece part (2).

Description

Technical Field

[0001] The present invention relates to a timepiece assembly consisting of at least two timepiece parts, a timepiece movement and a timepiece comprising at least one such timepiece assembly, and a method for producing such a timepiece assembly. Background Art

[0002] Ceramics are increasingly used in timepieces, for example to form timepiece arbors, since their intrinsic mechanical properties (particularly hardness) and their insensitivity to magnetic fields are very advantageous for many timepiece components. It is also known to use ceramics for timepiece exteriors.

[0003] If at least one of the components involved is made of ceramic, the traditional solutions for assembling watch parts are tricky. When the second component of the assembly is not made of ceramic, some solutions take advantage of the properties of this second component. Therefore, these solutions impose constraints on the manufacture of the second component of the assembly. In addition, when discussing, for example, assembling two watch parts both made of ceramic, these solutions are not always suitable. In this case, it is known to use gluing, the first disadvantage of which is the need to fully control the amount and alignment of the glue and to keep the parts aligned when the glue solidifies and dries, and the second disadvantage of which is that it depends on the possible deterioration of the glue over time. Alternatively, one can try to fasten two ceramic watch parts together by driving, which is complicated because the driving force has the risk of destroying one of the parts. In addition, when the ceramic component has a shape that makes it particularly fragile, driving is not suitable.

[0004] The object of the present invention is therefore to improve the production of timepiece components and, in particular, to define a timepiece component solution particularly suitable for the use of ceramics and particularly for timepiece components involving the assembly of two ceramic parts.

[0005] More precisely, an object of the invention is to define a timepiece assembly solution that is reliable, durable and easy to use. Summary of the Invention

[0006] To this end, the present invention is based on a method for producing a watch component, which includes a first watch part and at least one second watch part different from the first watch part, the first watch part including a connecting portion, the connecting portion including at least one opening, the second watch part including at least one structure, the connecting portion of the first watch part and / or the structure of the second watch part forming a sintered zirconia-based part, the method including a step of joining together by heat treatment, the heat treatment being predetermined to cause a phase change of the sintered zirconia-based part from a tetragonal phase to a monoclinic phase, or vice versa, the phase change causing a dimensional change of at least the sintered zirconia-based part so as to join the connecting portion of the first watch part and the structure of the second watch part together.

[0007] The present invention also relates to a watch assembly comprising a first watch component and at least one different second watch component, wherein the first watch component comprises a connecting portion based on tetragonal zirconia, the connecting portion comprising at least one opening, and the second watch component comprising at least one structure; or the watch assembly comprises a first watch component and at least one different second watch component, the first watch component comprises a connecting portion comprising at least one opening, the second watch component comprising at least one structure, the structure being based on monoclinic zirconia, the first watch component and the second watch component being clamped together on the at least one structure of the second watch component, without the opening in the first watch component being deformed.

[0008] The invention is more particularly defined by the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The objects, features and advantages of the present invention are described in detail in the following non-limiting description of specific embodiments with reference to the accompanying drawings, in which:

[0010] Figure 1 Represents a top view of a watch case comprising a ceramic applique assembled onto a ceramic bezel disc according to a first embodiment of the invention.

[0011] Figure 2 Partial side view showing a section of the outer ring disc at the level of a timepiece assembly according to a first embodiment of the invention.

[0012] Figure 3 A partial top view of the bezel at the level of a timepiece assembly according to a first embodiment of the invention is shown.

[0013] Figure 4 A top view of a second embodiment of the present invention showing an outer ring disc including assembled ceramic appliqués.

[0014] Figure 5 Partial side view showing a section of the outer ring disc at the level of a timepiece assembly according to a second embodiment of the invention.

[0015] Figure 6 A partial top view of the bezel at the level of a timepiece assembly according to a second embodiment of the invention is shown.

[0016] Figure 7 A top view showing an assembled appliqué on a dial forming a timepiece assembly according to a third embodiment of the invention.

[0017] Figure 8 Partial side view showing a section of the dial at the level of a timepiece assembly according to a third embodiment of the invention.

[0018] Figure 9 A top view of an outer ring disc including an assembled ceramic appliqué is shown according to a fourth embodiment of the present invention.

[0019] Figure 10 A top view of an assembly of an outer ring and an outer disk according to a fifth embodiment of the present invention is shown.

[0020] Figure 11 A partial side view showing a cross section of a timepiece assembly according to a fifth embodiment of the present invention.

[0021] Figure 12 Partial side view showing a section of a timepiece assembly according to a variant of the fifth embodiment of the invention.

[0022] Figure 13 A perspective view showing a timepiece assembly including a pinion assembled to an arbour according to a sixth embodiment of the present invention.

[0023] Figure 14 A side view showing a cross section of a timepiece assembly according to a sixth embodiment of the present invention.

[0024] Figure 15 A plan view showing a timepiece assembly according to a sixth embodiment of the present invention.

[0025] Figure 16 Side view showing a section of a timepiece assembly comprising a pinion assembled to an arbour according to a seventh embodiment of the invention.

[0026] Figure 17 A side view showing a cross section of a timepiece assembly according to an eighth embodiment of the present invention.

[0027] Figure 18Graph showing the relative deformation of a black zirconia sample as a function of temperature T during the preliminary heat treatment and the heat treatment for joining together in one embodiment of the present invention.

[0028] Figure 19 Indicates Figure 18 Temperature variation of the black zirconia sample over time during the measurement. DETAILED DESCRIPTION

[0029] To simplify the description, by convention, we refer to the vertical direction as the direction perpendicular to the plane of the timepiece (e.g., perpendicular to the plane of the dial), that is, the direction from which a user views the timepiece to read the time. The adjective "above" will be used to refer to a position relative to the timepiece that enables the time to be read in the vertical direction, as opposed to the adjective "below." By extension, these definitions will apply to timepiece components that form timepiece subassemblies, even without regard to their position within the timepiece, and will refer to their intended position within the timepiece.

[0030] The adjective "lateral" will be used to denote a direction perpendicular to the vertical. A side view is a view in the lateral direction.

[0031] The invention advantageously relates to a method for producing a timepiece assembly. The purpose of this method is to assemble at least two different timepiece components in a joined together manner (whether fixed or movable relative to each other) to form a joined integral assembly, which we call a timepiece assembly.

[0032] According to the concept of the invention, at least one watch component of the watch assembly consists essentially of sintered zirconia, that is to say consists entirely or partially of sintered zirconia and / or advantageously contains at least 50% by weight of sintered zirconia. We will use the expression "based on" a watch component to indicate the fact that it contains at least 50% by weight of sintered zirconia. Thus, sintered zirconia can be combined with another material to form a composite material. Moreover, the watch component will advantageously be based entirely on sintered zirconia, or made entirely of sintered zirconia, that is to say its material will be the same throughout its entire volume. We will hereinafter use the simplified expression "sintered zirconia watch component" or "sintered zirconia watch component portion" to refer to all the above-mentioned configurations.

[0033] The sintered zirconia used is notably present at the level of the connecting portion of the timepiece component, that is to say the portion containing the connecting surface of said timepiece component consists mainly of sintered zirconia.

[0034] Furthermore, according to the present invention, sintered zirconia has a stable tetragonal phase structure capable of undergoing a phase transformation from a tetragonal phase to a monoclinic phase through heat treatment at ambient pressure and relatively low temperatures, particularly between 100°C and 400°C. Many factors contribute to achieving this specific property of phase transformation capability, as described above. Examples of zirconia exhibiting this property will be described below, but this is by no means the case for all tetragonal zirconia. Hereinafter, the simplified expression "specific tetragonal phase" will be used to refer to the tetragonal phase of zirconia exhibiting this specific property, as explained above.

[0035] Note that zirconium oxide can be observed and its structure can be identified in tetragonal, monoclinic or even cubic phases. For this reason, X-ray diffraction measurements, for example, enable direct structural characterization, even allowing the precise determination of the concentration of each tetragonal, monoclinic and cubic phase in the case of a multiphase structure.

[0036] It is further noted that when the tetragonal phase transforms into the monoclinic phase, the size of the zirconia changes by increasing its volume. As described below, this phenomenon, exploited by the present invention, enables indirect observation of the zirconia phase via dilatometry. This observation of the zirconia's dimensional changes over time and / or temperature allows the occurrence of the tetragonal to monoclinic phase transition and vice versa, and even the kinetics of such phase transitions to be determined. Thus, when the initial phase and initial size of the sample are known, dilatometry enables precise indirect phase determination based on dimensional changes.

[0037] In another alternative, a person skilled in the art may determine the phase of the zirconium oxide by any other known means. This possibility of being able to determine the phase of the zirconium oxide and its phase transitions enables a person skilled in the art to easily and empirically analyze a particular zirconium oxide and determine, for example using the method described below, whether it can be used to form a connecting portion of a timepiece component.

[0038] Finally, in all the embodiments envisaged, it is advantageous to use technical zirconias and therefore sintered technical zirconias. The adjective "technical" refers to the high-performance properties of the zirconias chosen. In fact, technical zirconias can have very high mechanical, thermal and even electrical and / or biochemical properties, as well as chemical inertness and non-magneticity, which makes them suitable for forming watch components. The technical zirconias used here are characterized by their stable crystalline phases (for example, having a predominantly tetragonal phase) and a chemical composition that makes them stable with respect to phase transitions from tetragonal to monoclinic. The powders used to make the technical zirconias are obtained from purified synthetic powders rather than natural mineral powders.

[0039] A method of producing a timepiece component will now be described.

[0040] The preliminary step of the method according to this embodiment consists in providing at least two different timepiece components intended to be assembled to form an assembly joined together.

[0041] The first timepiece component comprises at least one first connection portion made of or based on sintered zirconia in the specific tetragonal phase described above. This first connection portion forms a female connection intended to receive a connection with a second timepiece component, described below. Thus, this first connection portion has an overall open shape, or more generally comprises at least one opening, the term "opening" being intended to encompass a variety of shapes, specific examples of which will be mentioned below.

[0042] The shape of the second timepiece component matches that of the first timepiece component, in particular the second connection portion forms a male connection element intended to mate with the first connection portion of the first timepiece component (that is, the opening in the first timepiece component). We will use the general term "configuration" to denote the shape of this second connection portion intended to mate with the opening in the first timepiece component. This configuration can have a variety of shapes, as long as it is capable of mating with the opening in the first timepiece component to achieve the connection between the two timepiece components.

[0043] The production method comprises a first step of subjecting the first watch component to a preliminary heat treatment to induce a first phase transformation of the sintered zirconia from its tetragonal to monoclinic phase, at least at the level of the first connecting portion. This first phase transformation causes an enlargement of the opening in the first watch component. This dimensional change of the first watch component is essentially due to the phase transformation. The phase transformation may be partial, but will be selected to achieve the desired enlargement.

[0044] The tetragonal phase of the sintered zirconia of the first watch component is advantageously a specific phase, and this phase is selected because it tends to relatively easily (that is, by phase transformation to a monoclinic phase at ambient pressure and preferably at a relatively low temperature between 100°C and 400°C). Performing the operation at ambient pressure or even at a relatively low pressure below 2atm and in the absence of stress makes it possible to avoid subjecting the watch component to excessive stress and to simplify the method using a furnace of simple construction without complications due to high pressure. This is advantageous because watch components are typically characterized by very small sizes and / or very small parts with particularly fragile shapes. Therefore, if watch components are subjected to stress, there is a risk of fracture of the watch component and / or damage to its geometric integrity. In addition, this heat treatment appears to achieve sufficient results in a relatively short time (e.g., one hour or even several hours). More generally, the duration of the heat treatment can be between 30 minutes and 10 hours. In all cases, the heat treatment advantageously takes less than 10 hours or even less than 5 hours or even less than 3 hours. This heat treatment can also be carried out in a neutral atmosphere or in air and in all cases does not require any additional external input, such as the addition of water. Given the above conditions, the heat treatment has the advantage of being able to be carried out using a simple furnace. Alternatively, the addition of water can be used.

[0045] The production method then comprises a second step, which in particular and advantageously consists in assembling the two watch components at ambient temperature into an intermediate configuration, such that the structure of the second watch component is positioned at least partially through the opening in the first watch component. In this intermediate configuration of the assembly of the two watch components, the two watch components are in their final position relative to each other, but have not yet been joined. Consequently, the respective dimensions of the opening and the structure, enlarged by the preliminary heat treatment, are such that the structure is positioned in the opening and separated from the surface of the opening by a small distance, which represents the gap between the two watch components. Consequently, at this stage, the two watch components do not touch each other, or do not touch each other too much, in this intermediate configuration.

[0046] Advantageously, a means is used to maintain this intermediate form in a stable manner. For example, one or both watch components may be held by a support or have complementary shapes that enable them to be held relative to each other. Alternatively, this means may take the form of an intermediate adhesive that disappears during the heat treatment process of joining them together.

[0047] The production method comprises a third step consisting in subjecting the watch components in their intermediate form to a heat treatment for joining them together, in order to induce a second phase transformation of the sintered zirconia of the first watch component, which partially or completely returns from the monoclinic phase to the tetragonal phase, this second phase transformation causing the opening in the first watch component to shrink, in order to join the first and second watch components of the watch assembly in their final form. During this step, the sintered zirconia of the first component returns substantially to its initial phase and its initial dimensions, as they had before the preliminary heat treatment.

[0048] This combined heat treatment is also advantageously performed at ambient pressure or even at a relatively low pressure of less than 2 atm. Furthermore, in one embodiment, it is performed at a temperature between 1100°C and 1300°C. Likewise, its duration may be between one and several hours, more typically between 30 minutes and 10 hours. This combined heat treatment advantageously has a duration of less than 10 hours, or even less than 5 hours, or even less than 3 hours.

[0049] Such a connection between the two timepiece parts may consist in joining the two timepiece parts together by clamping a connection surface delimiting an opening in the first timepiece part onto a formation of the second timepiece part during a second change in the dimensions of the first timepiece part. Alternatively, such a connection may entail retaining the second timepiece part in a housing formed by the opening in the first timepiece part, the two timepiece parts being connected to form a timepiece assembly, wherein the second timepiece part remains movable relative to the first timepiece part, in particular in translation and / or rotation.

[0050] Note that this production method is compatible with the use of a second component that can comprise a variety of different materials, in particular at the level of its second connecting portion comprising said construction. In particular, at least the construction of the second timepiece component can also be made of ceramic.

[0051] Note that the material of the second timepiece component is selected so that any deformation thereof due to thermal expansion during the heat treatment for joining together does not restrict the aforementioned deformation of the first timepiece component, thereby not opposing the connection achieved through the phase transformation of the zirconium oxide of the first timepiece component and, therefore, not opposing the assembly. In particular, any dimensional changes due to thermal expansion of the second timepiece component in the assembly do not impose stresses on the first timepiece component that exceed its elastic limit, in order to prevent its breakage.

[0052] An advantage of the concept of the present invention is that it can be used for a variety of timepiece components which may comprise a variety of materials and / or have a variety of shapes.

[0053] therefore, Figures 1 to 17A timepiece component obtained by applying the production method described above is shown by way of example.

[0054] For simplicity, in these figures, the same reference numerals are used to designate the first and second timepiece components and their corresponding connections, even if the components and their shapes are different.

[0055] therefore, Figure 1 A first embodiment is shown, in which a watch case 100 is provided with a bezel 4, which itself comprises an assembled bezel disc comprising a cylindrical applique fixed thereto by the method described above. Thus, in this first embodiment, the timepiece assembly 3 is the assembled bezel disc, the first timepiece component 1 is the bezel disc comprising a cylindrical opening 10 formed in the bezel disc, and the second timepiece component 2 is a cylindrical applique, the construction 20 of which is the cylindrical portion of the applique, which is fixed to the bezel disc by the method described above. Figure 2 and Figure 3 Especially visible in.

[0056] In this embodiment, the opening 10 and the formation 20 have a diameter of approximately 2.2 mm. Alternatively, the opening 10 and the formation 20 may be of some other shape and, more generally, are inscribed within a circle Ca having a diameter of 2.2 mm once the appliqué has been fixed to the bezel.

[0057] In this embodiment, the first watch component 1 (i.e., the bezel) is made of, or based on, or consisting essentially of, black zirconium oxide. In the described method, this sintered zirconium oxide is more specifically suitable for phase transformation. The second watch component 2 (i.e., the appliqué) is made of, or even based on, or consisting essentially of, blue zirconium oxide. Here, this blue zirconium oxide remains insensitive to the heat treatment of the third joining step.

[0058] Black zirconium oxide is a tetragonal zirconium oxide that is stable at ambient temperature due to the addition of metal oxides, such as oxides of cerium and / or calcium and / or magnesium and / or yttrium. The black color is obtained by adding 1.5-5% by weight of spinel of the (CoZn)(FeAl)2O4 type to a base composition comprising 1.8 to 5 mol% of a metal oxide (such as Y2O3), the balance being ZrO2, as described, for example, in document EP1857428. Due to the influence of high temperatures, this black zirconium oxide is suitable for a partial or complete transformation from a tetragonal phase to a monoclinic phase. Depending on the temperature parameters, the duration of this phase transformation can be of the order of one hour or even several hours. In addition, this phenomenon can be accelerated in humid air.

[0059] Blue zirconium oxide is a tetragonal zirconium oxide that is stable at ambient temperature due to the addition of metal oxides, typically oxides of cerium and / or calcium and / or magnesium and / or yttrium. The blue color is obtained by adding 2 to 4 weight percent of spinel CoAl2O4 particles to a base composition containing 3 to 5 mol percent of a metal oxide (e.g., Y2O3), the balance being ZrO2.

[0060] The characteristics of the zirconium oxide powder used to prepare these timepiece components are listed in Table 1 below, and the characteristics of the steps for producing these timepiece components are detailed in Table 2.

[0061] Table 1 - Types of Zirconia Used in the Embodiments

[0062]

[0063] *According to EP1857428

[0064] **Those skilled in the art know it as "cobalt blue", which is widely used in ceramic coloring.

[0065]

[0066] The heat treatment is carried out in ambient air in a non-hermetically sealed electrically heated furnace of standard construction for technical ceramics and capable of reaching temperatures of approximately 1400° C. to 1700° C.

[0067] Assembled outer ring discs were produced in a test setting. Specifically, the black zirconium oxide outer ring discs, each containing a 2.186 mm diameter opening designed to receive a blue zirconium oxide appliqué, were heated to 250°C in ambient air for two hours and then cooled to ambient temperature. This initial heat treatment resulted in a 0.01 mm diameter expansion of the opening.

[0068] A blue patch is placed in each opening of the disc, after which these timepiece components, in their intermediate state, are heated to 1150° C. for 1.5 hours. The black zirconium oxide disc returns to its original dimensions, which makes it possible to clamp the patch.

[0069] Table 3 below summarizes the details of these various steps for one embodiment:

[0070] Table 3 - Steps for preparing two black zirconia outer ring discs and dimensional measurement results in this embodiment

[0071]

[0072] According to Table 3 above, the average linear deformation of the black zirconia disk caused by the phase change can be estimated to be 0.57% based on the inner diameter measurement results.

[0073] In order to clearly depict the dimensional changes exploited by the present invention, a dilatometer was used to observe the behavior of a control sample in the form of a cuboid having a square base with a side length of 4.5 mm and a height of 13 mm. The main result obtained with the help of the dilatometer is the measurement of the linear deformation of the sample with respect to time and temperature.

[0074] Figure 18 The relative deformation ε of the black zirconium oxide sample measured by dilatometer is plotted as a function of temperature T. In the context of the present invention, this variation represents the expansion during the preliminary heat treatment and during the heat treatment of joining together. The arrows on the expansion curves indicate the changes over time. Figure 19 Indicates Figure 18 Temperature changes of the black zirconia sample during the dilatometric measurement are shown. Figure 18 In the figure, parts A, B and C represent the initial heat treatment. Part A shows a linear increase in the temperature of the sample to 180°C, accompanied by a linear expansion of the sample without a phase change. Part B shows a deformation of approximately 0.5% during 10 hours at a constant temperature of 180°C. This reflects the expansion caused by the phase change from tetragonal to monoclinic. Part C represents cooling to ambient temperature. The rest of the curve (marked D, E and F) represents the heat treatment of joining together, which causes the initial dimensions to be restored due to the phase change from monoclinic to tetragonal during heating at 1200°C. In part D, the expansion of the sample follows the increase in temperature in a linear manner. Thereafter, in part E, the expansion decreases in a nonlinear manner due to the phase change, and in part F, the expansion resumes linear growth. Part G shows a linear contraction during the temperature drop. Note that, apart from the nonlinear change in deformation due to the phase change, the deformation with respect to temperature remains linear with the normal thermal expansion coefficient of zirconia.

[0075] Phase transformations during heat treatment occur over a relatively wide temperature range between 100°C and approximately 400°C for the zirconium oxides studied, with the maximum rate of change being around 180°C. The phase transformation from monoclinic to tetragonal during the bonding heat treatment can already be observed as a reduction in expansion (section E) towards 600°C, but it becomes permanent only after cooling well above 800°C (typically around 1200°C). Therefore, if the bonding heat treatment is stopped before reaching 800°C, the recovery due to the phase transformation is incomplete, and the sample will remain significantly expanded after cooling to ambient temperature.

[0076] Table 4 below presents the proportion of the monoclinic phase in black and blue zirconia before and after heat treatment at 180°C for 10 hours in ambient air, as assessed using two different methods. Clearly, there is a small discrepancy between the monoclinic phase proportion measured by dilatometry and that obtained from X-ray diffraction measurements. The smaller values ​​obtained by the latter method can be attributed to the low penetration of X-rays in the measured samples, which is approximately a few micrometers.

[0077] Table 4

[0078]

[0079] Figure 4 1 shows a top view of a timepiece assembly according to a second embodiment. This timepiece assembly 3 includes a ceramic appliqué as a second timepiece component 2, which is assembled onto a first timepiece component 1 consisting of an outer bezel.

[0080] The appliqué comprises a visible portion of triangular shape, which is extended by a formation 20 in the form of a stud inserted into the opening 10 in the outer ring disc. In this second embodiment, the opening 10 has a non-cylindrical shape, in the form of a cylinder with a flat portion, and the formation 20 of the appliqué is likewise a stud with a non-cylindrical geometry complementary to that of the opening 10 and therefore comprising a flat portion, as in Figure 5 and Figure 6 This non-cylindrical geometry has the function of correctly orienting the applique relative to the outer ring disc. Once the applique has been fixed to the disc, the cross section of the opening 10 and the structure 20 can be inscribed in a circle Cb with a diameter of 1 mm, as shown in FIG. Figure 6 shown.

[0081] Figure 7 and Figure 8 A timepiece assembly 3 in the form of a dial is shown, which enables the assembly of a first timepiece component 1 consisting of a dial plate with a plurality of second timepiece components 2 consisting of appliques 21, 22, 23, 24. These appliques are notable in that they each comprise two formations in the form of cylindrical studs designed to be housed in corresponding openings 10 of the dial plate in such a manner as to enable their indexing relative to the dial plate. For example, Figure 8 A cross-sectional view through appliqué 21 positioned at position 12h on the dial plate is shown. Two pegs 210, 211 of appliqué 21 are housed in corresponding openings 110, 111 of the dial plate. Openings 110, 111 and structures 210, 211 have a diameter of approximately 0.25 mm. In particular, once appliqué 21 has been secured to the dial plate, openings 110, 111 and structures 210, 211 can be inscribed within a circle Cc having a diameter of 0.25 mm.

[0082] Figure 9 The fourth embodiment shows a watch assembly 3, which comprises a first watch component 1 corresponding to the outer ring, which is assembled to a second watch component 2 corresponding to the applique. The applique can be similar to Figure 8 Finally, the fourth embodiment corresponds to the structure of the clock assembly 3 / opening structure and is assembled to the outer ring plate. Figure 4 The second embodiment shown and Figure 7 A combination of the third embodiment.

[0083] Figure 10 and Figure 11 1 shows a timepiece 3 in a fifth embodiment. The first timepiece component 1 is an outer ring comprising an opening 10 in the form of a peripheral groove. The second timepiece component 2 is an outer disc, the periphery of which forms a structure 20 to be received in the opening 20, so that the sides of the opening 10 clamp the outer periphery of the structure 20 forming the outer disc. In this embodiment, the opening 10 and the structure 20 have a total diameter of approximately 47 mm. In particular, once the outer disc is clamped in the outer ring, the opening 10 and the structure 20 can be inscribed in the outer ring. Figure 10 In the circle Ce with a diameter of 47 mm shown in FIG.

[0084] Figure 12 A variation of the fifth embodiment is shown in which the configuration 20 of the outer ring comprises pegs designed to be received in openings 10 in the outer ring. For example, Figure 12 A horizontal cross-sectional view shows pegs housed in openings in the outer ring. In this embodiment, the pegs are oriented vertically and arranged in openings that are also arranged around a vertical axis. The pegs are distributed regularly or irregularly around the circumference of the outer ring. The openings are distributed in a corresponding pattern on the outer ring. Those skilled in the art will understand how to adjust the shape and position of the openings (and the corresponding pegs) based on the different linear deformations of the inner diameter of each opening and the distances between them. By way of example, opening 10 and the corresponding structure 20 have a diameter of approximately 1 mm.

[0085] Figures 13 to 15 A sixth embodiment is shown of a timepiece assembly comprising a pinion, in particular an escapement pinion, mounted on an arbour. A first timepiece component 1 is the pinion, and a second timepiece component 2 is the arbour. The pinion comprises an opening 10 with a square cross-section, and the arbour comprises a portion (which forms a construction) whose cross-section is complementary to that of the opening, so that the timepiece assembly is a pinion mounted on a square on the arbour. The square shape allows, on the one hand, for indexing the position of the pinion relative to the arbour, and also constitutes a torque transmission element between the arbour and the pinion. Once the pinion has been fixed to the arbour, the corresponding geometry of the cross-section of the opening 10 and the construction 20 can be inscribed in a circle Cf with a diameter of 0.3 mm.

[0086] Figure 16 A seventh embodiment of a timepiece assembly 3 is shown, which also comprises a pinion mounted on an arbour. In this embodiment, the first timepiece component 1 is an arbour comprising a groove forming an opening 10 on its periphery. The second timepiece component 2 is a pinion comprising a protrusion forming a formation 20 intended to cooperate with the opening 10.

[0087] The present invention is naturally not limited to the above-mentioned embodiments or the specific geometric shapes described. More generally, the first watch component 1 is a concave component including at least one opening 10, and the second watch component 2 is a convex component including at least one structure 20 designed to be inserted into the opening 10, the structure and the opening being able to have any suitable shape and any suitable size. For example, the opening 10 can be a through opening or a blind opening. The opening 10 can, for example, take the form of a hole or a groove. The opening 10 can preferably have a conical, cylindrical or non-cylindrical, oval or elliptical or polygonal shape, with a circular or non-circular, elliptical, polygonal cross-section, and / or include teeth or at least one flat portion. The cross-section receiving the opening can be open or closed. The first watch component 1 may include multiple openings 10.

[0088] The formation 20 constitutes a portion of the second timepiece component 2. This portion may consist of the outer periphery or pegs of the second timepiece component 2, or more generally, a protrusion on the timepiece component 2. More generally, the formation may correspond to a portion that at least partially constitutes the body of the second component, such as the outer wall of the timepiece component 2, or the formation may be a specific additional portion, such as a peg protruding from the body of the second timepiece component. The formation may include a plurality of different parts, such as a plurality of pegs, for example two pegs.

[0089] The cross-section of the formation 20 matches that of the opening 10 and can therefore have a cylindrical or non-cylindrical, conical, polygonal cross-section, and / or include teeth or at least one flat portion. The dimensions of the formation 20 and the corresponding opening 10 are therefore substantially identical, so as to achieve a clearance in the temporary configuration that facilitates relative positioning while ensuring minimal mobility between the two watch components during the temporary positioning of the assembly before they are joined. The distance between the two watch components at their connection level (i.e., the clearance between the formation and the opening) is advantageously less than or equal to 4 μm or even less than or equal to 2 μm. This distance is also advantageously greater than or equal to 1 μm or even greater than or equal to 1.5 μm. This dimension takes into account the linear increase in the dimensions of the first watch component, and more specifically its opening 10, during the preliminary heat treatment, which is approximately 0.4% to 1.5%. The geometry of the timepiece components will advantageously be chosen so as to achieve sufficient clearance before the heat treatment, so as to enable them to be assembled with minimal clearance in each case, while at the same time being able to be satisfactorily joined together by the heat treatment within an acceptable time. Thus, the dimensions of the construction may lie between those of the opening in the first timepiece component and those of the same opening enlarged by the preliminary heat treatment.

[0090] As mentioned above, the size of the configuration and opening can vary. For example, after assembly, the respective opening cross-sections and configuration cross-sections of the first and second watch components can be inscribed in a circle having a diameter of 50 mm, or even 30 mm, or even 5 mm, or even 3 mm, or even 2 mm, or even 1 mm, or even 0.5 mm. Before the first step, the at least one opening has a first size. After the first step, the at least one opening has a second size. The at least one configuration of the second component has a third size between the first and second sizes of the at least one opening. Within manufacturing tolerances, the third size can particularly be of the same order of magnitude as the first size.

[0091] A watch assembly may include multiple second watch components assembled to the same first watch component, or multiple first watch components assembled to the same second watch component. In this case, the watch assembly thus includes more than two watch components. Such an assembly can be produced using the same method, wherein at least three watch components can be assembled simultaneously. Alternatively, the assembly method can be sequential, so that the components are assembled two by two, taking into account that the pre-assembled components are separated each time a preliminary heat treatment is performed and rejoined each time a heat treatment is completed to join them together.

[0092] The present invention is naturally not limited to the embodiments described above by way of example, in which the first watch component can be a bezel, an outer ring, an outer ring, or a dial, and the second watch component can be an appliqué or a bezel. The present invention can be extended to many watch components, particularly in the field of watch exteriors, such as any component within a watch case, a dial, or a wristband.

[0093] The present invention is not limited to the field of watch exteriors but can also be applied to the field of assembling two parts of a watch movement. For example, as mentioned above, the first part can be a pinion, and the second part can be an arbour, or vice versa. More generally, the present invention can be applied to any part of an assembled movement, such as a ruby ​​or any toothed component such as a lever, cam, or arbour.

[0094] The invention also makes it possible to assemble a second component to a first component by joining the first and second components together while maintaining a degree of freedom between the two components, the second timepiece component remaining movable relative to the first. Figure 17 By way of example, a timepiece assembly 3 is shown in which a formation 20 of a second timepiece component 2 is enclosed within an opening 10 of a first timepiece component 1. Thus, the second timepiece component 2 is movable translationally and rotationally within the opening 10, but its formation 20 cannot escape from the opening 10, the mouth of which is smaller than the formation 20. Consequently, the two timepiece components are joined together. Thus, in such an embodiment, the heat treatment for joining together results in at least one formation 20 of the second timepiece component 2 being trapped within the housing defined by the at least one opening 10 of the first timepiece component 1, and the two timepiece components 1, 2 are joined together in a manner movable relative to one another.

[0095] On the other hand, as mentioned above, the present invention has the advantage of being compatible with at least one first timepiece component made of undeformed tetragonal sintered zirconia, which, if subjected to an assembly method different from that of the present invention, such as actuation, would induce internal stresses that would pose a non-negligible risk of ceramic fracture. Consequently, the first timepiece component, after assembly, is free of internal stresses, particularly at the level of the connection zone. More specifically, a specific tetragonal zirconia is used that is capable of transforming to a monoclinic phase at ambient pressure at temperatures above 100°C, or even between 100°C and 400°C.

[0096] The specific tetragonal zirconia of the first watch component can be in particular a sintered zirconia, in particular yttria-stabilized zirconia, in particular 3 mol % yttria-stabilized zirconia or 2 mol % yttria-stabilized zirconia. This zirconia can be colored by dyeing and / or impregnation. This zirconia may also include grains of a different grain size from the specific zirconia of the first watch component. As mentioned above, not all zirconias have the phase transformation ability selected by the present invention. To this end, multiple factors determine this property, and those skilled in the art will know how to identify a specific zirconia suitable for implementing the present invention. For example, the size of the grains of the zirconia after sintering appears to have an impact on the zirconia's ability to undergo this phase transformation. Thus, the same black zirconia as described in detail above, but sintered at a lower temperature using a shorter thermal cycle (e.g., at 1300°C for approximately 5 minutes, rather than at 1350°C for 1 hour), does not exhibit this phase transformation ability.

[0097] Even if the invention can be realized based on only one connecting portion made of such zirconium oxide (comprising at least one opening), it is advantageous to use a first timepiece component consisting entirely of this same material.The first timepiece component advantageously takes a monolithic form, ie in particular in one piece.

[0098] The material of the second component can also be ceramic or even zirconium oxide, particularly one that lacks the specific properties of the zirconium oxide of the first watch component. Therefore, this zirconium oxide is selected to be insensitive, or negligibly insensitive, to the heat treatment of the production process compared to the first watch component. Specifically, this zirconium oxide exhibits no phase transformation, or only a small phase transformation, during the heat treatment of joining. Its coefficient of thermal expansion is substantially similar to or less than that of the zirconium oxide of the first component, so as not to induce stresses in the first component that exceed its elastic limit. As mentioned above, not all zirconium oxides possess the phase transformation capabilities of the zirconium oxide selected for the present invention. Therefore, multiple factors determine this property, and those skilled in the art will know how to identify a specific zirconium oxide suitable for implementing the present invention. This zirconium oxide can be colored by dyeing and / or impregnation. It can also have grains that differ in size from the specific zirconium oxide of the first watch component. Therefore, if the properties of the two black zirconium oxide components, such as their grain size, are carefully selected, they can be assembled using the present invention. More generally, the zirconium oxide of the second component differs from that of the first component. It can have different finishes, for example a matte finish compared to a polished finish. More generally, the material of the second timepiece component can be any technical ceramic that is insensitive to heat treatment. It can be, for example, aluminum oxide Al2O3, boron nitride BN, boron carbide B4C, silicon nitride Si3N4, silicon carbide SiC, aluminum nitride AlN, borides and nitrides of Ti, Zr and Hf, or sapphire or ruby ​​or crystalline quartz. Alternatively, the material of the second component can be a refractory metal (Pt, W), a cermet or a glass (fused silica glass).

[0099] The invention also relates to a timepiece movement comprising one or more timepiece components as described above.

[0100] The invention also relates to a timepiece comprising at least one timepiece assembly as described above or such a timepiece movement.

[0101] Note that the present invention has been described in detail based on a concave connecting portion of a first component, which is able to be joined together due to a phase transformation of the zirconium oxide constituting the matrix of this connecting portion. Alternatively, this phase transformation of the specific zirconium oxide constituting the matrix of the connecting portion as described above can be used to achieve the joining together of a second watch component having a connecting portion based on sintered zirconia (more precisely, a construction which forms a convex connecting portion). In fact, according to the principle of the above-mentioned preliminary heat treatment, if this construction undergoes a full or partial phase transformation from a tetragonal phase to a monoclinic phase, it produces an expansion, i.e. an increase in its size, which can also lead to clamping in the opening of the first component. Therefore, all the above-mentioned embodiments can be implemented based on a sintered zirconia portion of the construction of the second watch component that changes phase and increases its size. Therefore, after the two watch components are joined together, this sintered zirconia portion undergoes a phase transformation from tetragonal to monoclinic.

[0102] In this embodiment, at least the connecting portion of the first timepiece component may be made of one of the materials mentioned for the second timepiece component in the preceding embodiments.

[0103] The invention therefore also relates to a method for producing a timepiece component in which the construction of the second timepiece part forms a part based on sintered zirconium oxide, the method comprising the following steps:

[0104] o assembling the two timepiece components into an intermediate configuration such that at least one feature of the second timepiece component is located within an opening in the connecting portion of the first timepiece component;

[0105] o Subjecting the watch components in their intermediate forms to a heat treatment for joining them together so as to cause a phase transition of the zirconium oxide of the structure of the second watch component from a tetragonal phase to a monoclinic phase, which phase transition causes expansion of at least one of the structures of the second watch component, thereby joining the first watch component and the second watch component of the watch assembly together in their final form.

[0106] Note that in this embodiment mode, the conditions of the heat treatment for joining together correspond to the preliminary heat treatment in the above-described embodiment mode.

[0107] According to another method, at least two connecting parts of two watch parts (i.e. the connecting parts including the opening and the structure) can be made of the same material based on the specific sintered zirconia described in detail above. In this case, during the heat treatment for joining together, the two parts to be joined can undergo dimensional changes. The structure, which is initially in the tetragonal phase, will undergo a phase transition from the tetragonal phase to the monoclinic phase in the range of 100°C-400°C at the beginning of the heat treatment for joining together. Within this range, the opening can only increase in size or remain unchanged. Therefore, during the temperature increase, the two parts are in a state of expansion and may already be joined together. During the remaining time of the heat treatment for joining together, in the range of 400°C-1300°C, the two parts that are in the monoclinic phase and may already be joined together will simultaneously undergo a phase transition from monoclinic to tetragonal until the final joining together is achieved and remain in the tetragonal phase as described above.

[0108] Finally, the method of the invention exploits the concept of modifying the dimensions of at least a portion of a sintered zirconia-based material during the phase transition from tetragonal to monoclinic and vice versa in order to join two timepiece components together.

Claims

1. A method for producing a watch component (3), wherein the watch component (3) comprises a first watch part (1) and at least one second watch part (2) different from the first watch part (1), the first watch part (1) comprising a connecting portion, the connecting portion comprising at least one opening (10), the second watch part (2) comprising at least one structure (20), the connecting portion of the first watch part (1) and / or the structure of the second watch part (2) forming a sintered zirconia-based part, the method comprising a heat treatment step of joining together, the heat treatment being predetermined to cause a phase transition of the sintered zirconia-based part from a tetragonal phase to a monoclinic phase, or vice versa, the phase transition causing a dimensional change of at least the sintered zirconia-based part so as to join the connecting portion of the first watch part (1) and the structure of the second watch part (2) together.

2. Method for producing a timepiece component according to claim 1, wherein the formation (20) of the second timepiece component (2) forms the sintered zirconia-based part, the method comprising the steps of: Assembling the first timepiece component (1) and the second timepiece component (2) into an intermediate configuration such that the at least one structure (20) of the second timepiece component (2) is located in the at least one opening (10) of the connecting portion of the first timepiece component (1); The watch component (3) in its intermediate form is subjected to the joining heat treatment so as to cause a phase transition of the zirconium oxide of the structure (20) of the second watch part (2) from a tetragonal phase to a monoclinic phase, said phase transition causing an expansion of the at least one structure (20) of the second watch part (2), thereby joining the first watch part and the second watch part of the watch component (3) together in their final form.

3. Method for producing a timepiece component (3) according to claim 1, wherein the connecting portion of the first timepiece part (1) forms the sintered zirconia-based portion, the method comprising the steps of: subjecting the first timepiece component (1) to a preliminary heat treatment in order to induce a first phase transition of the zirconium oxide of the connecting portion from a tetragonal phase to a monoclinic phase, the first phase transition causing an enlargement of the at least one opening (10) of the first timepiece component (1); Assembling the first timepiece component (1) and the second timepiece component (2) into an intermediate configuration such that the at least one structure (20) of the second timepiece component (2) is located in the at least one opening (10) in the connecting portion of the first timepiece component (1); The watch component (3) in its intermediate form is subjected to the joining heat treatment to cause a second phase transition of the zirconium oxide of the connecting portion of the first watch part (1) from a monoclinic phase to a tetragonal phase, the second phase transition causing the at least one opening (10) of the first watch part (1) to shrink, thereby joining the first watch part and the second watch part of the watch component (3) together in their final form.

4. Method for producing a timepiece component according to claim 3, wherein the preliminary heat treatment is carried out at ambient pressure or even at a pressure below 2 atm and at a temperature between 100°C and 400°C.

5. Method for producing a timepiece component according to any one of the preceding claims, in which the heat treatment of the joining together is carried out at ambient pressure or even at a pressure below 2 atm and at a temperature between 1100° C. and 1300° C., or at ambient pressure or even at a pressure below 2 atm and at a temperature between 100° C. and 400° C.

6. A method for producing a watch component according to any one of the preceding claims, wherein one of the first watch component and the second watch component comprises the sintered zirconia-based part, and the other of the first watch component and the second watch component is made of a material whose dimensional changes during the heat treatment of joining together are negligible relative to the dimensional changes of at least one sintered zirconia-based part.

7. Method for producing a watch component according to claim 6, wherein all or part of the other of the first watch component and the second watch component is based on a technical ceramic, such as zirconium oxide different from or the same as the zirconium oxide of the part based on sintered zirconium oxide, aluminum oxide (Al2O3), silicon nitride (Si3N4), boron nitride (BN), boron carbide (B4C), silicon carbide (SiC), aluminum nitride (AlN), borides and nitrides of Ti, Zr and Hf, sapphire, ruby ​​or crystalline quartz, or all or part of the other of the first watch component and the second watch component is made of a refractory material, such as a metal, a cermet or a glass, such as fused silica glass.

8. A method for producing a watch component according to any one of the preceding claims, wherein the cross-section of the at least one opening (10) of the connecting part of the first watch component (1) is inscribed in a circle with a diameter less than or equal to 50 mm or even less than or equal to 30 mm or even less than or equal to 5 mm or even less than or equal to 3 mm or even less than or equal to 2 mm or even less than or equal to 1 mm or even less than or equal to 0.5 mm, and / or the dimensional change of at least one sintered zirconia-based part after the preliminary heat treatment is between 0.4% and 1.5%, and / or the size of the at least one construction (20) is substantially equal to the size of the at least one opening (10) in the connecting part of the first watch component (1).

9. A method for producing a watch component according to any one of the preceding claims, wherein the at least one opening (10) in the connecting part of the first watch part (1) has a cylindrical or non-cylindrical shape, in particular a conical or oval or elliptical or polygonal shape, or has a polygonal or toothed cross-section or a cross-section with one or more flat parts, and / or the geometry of the at least one construction (20) of the second watch part (2) is complementary to the geometry of the opening (10) in the connecting part of the first watch part (1).

10. A method for producing a watch component according to any one of the preceding claims, wherein the watch component (3) comprises the second watch component (2) and at least one third watch component assembled to the first watch component (1), or the second watch component (2) comprises a plurality of structures (20) that cooperate with corresponding openings (10) in the first watch component.

11. A method for producing a watch component according to any of the preceding claims, wherein the step of subjecting the watch component (3) to the joining-together heat treatment results in the at least one opening (10) of the first watch component (1) being clamped to the at least one structure (20) of the second watch component (2) by shrinking the at least one opening (10) of the first watch component (1), and / or the at least one opening (10) in the first watch component (1) being clamped to the at least one structure (20) of the second watch component (2) by expanding the structure (20) and joining the first watch component (1) and the second watch component (2) together, or the step of subjecting the watch component (3) to the joining-together heat treatment results in the at least one structure (20) of the second watch component (2) being enclosed in a housing defined by the at least one opening (10) in the first watch component (1), the first watch component (1) and the second watch component (2) being joined together in a manner movable relative to each other.

12. A watch assembly comprising a first watch part (1) and at least one different second watch part (2), the first watch part (1) comprising a connecting portion based on tetragonal zirconia, the connecting portion comprising at least one opening (10), the second watch part (2) comprising at least one structure (20), or the watch assembly comprising a first watch part (1) and at least one different second watch part (2), the first watch part (1) comprising a connecting portion comprising at least one opening (10), the second watch part (2) comprising at least one structure, the structure being based on monoclinic zirconia, the first watch part (1) and the second watch part (2) being clamped on the at least one structure (20) of the second watch part (2), without the opening in the first watch part (1) being deformed.

13. A watch assembly comprising a first watch part (1) and at least one different second watch part (2), the first watch part (1) comprising a connecting portion based on tetragonal zirconium oxide, the connecting portion comprising at least one opening (10), the second watch part (2) comprising at least one structure (20), or the watch assembly comprising a first watch part (1) and at least one different second watch part (2), the first watch part (1) comprising a connecting portion comprising at least one opening (10), the second watch part (2) comprising at least one structure (20), the structure being based on monoclinic zirconium oxide, the first watch part (1) and the second watch part (2) being joined together in a manner movable relative to each other by positioning the at least one structure (20) of the second watch part (2) in a housing defined by the at least one opening (10) in the first watch part (1).

14. A timepiece assembly according to claim 12 or 13, wherein the connecting portion of the first timepiece part is based on tetragonal zirconia suitable for phase transformation to a monoclinic phase at a temperature of 100°C or even at a temperature between 100°C and 400°C at ambient pressure or even at a pressure below 2 atm.

15. A watch component according to any one of claims 12 to 14, wherein one of the first watch part and the second watch part of the watch component includes a part based on tetragonal or monoclinic zirconia, and the other of the first watch part and the second watch part of the watch component is based entirely or partially on a technical ceramic whose dimensional changes during the heat treatment of joining together are negligible compared to the dimensional changes of at least one part based on tetragonal or monoclinic zirconia, such as zirconium oxide different from the zirconium oxide of the part based on tetragonal or monoclinic zirconia, aluminum oxide (Al2O3), boron nitride (BN), boron carbide (B4C), silicon nitride (Si3N4), silicon carbide (SiC), aluminum nitride (AlN), borides and nitrides of Ti, Zr and Hf, or sapphire or ruby ​​or crystalline quartz, or the at least one construction (20) of the second watch component (2) is made of a refractory material, such as a metal, a metal ceramic or a glass, such as fused silica glass.

16. A timepiece assembly according to any one of claims 12 to 15, wherein the at least one structure (20) of the second timepiece part (2) is a protrusion or a peg or part of the body of the second timepiece part (2), or the first timepiece part (1) is a bezel or a bezel ring and the second timepiece part (2) is a bezel disc, or the first timepiece part (1) is a bezel disc, a bezel, a dial or a wristband and the second timepiece part (2) is an external part, such as an appliqué, or wherein the first timepiece part (1) is a pinion, a lever, a cam, a ruby ​​or a toothed part, the pinion being, for example, an escapement pinion, and the second timepiece part (2) is an arbour, or the first timepiece part (1) is an arbour and the second timepiece part (2) is a pinion, a lever, a cam or a toothed part.

17. A timepiece comprising the timepiece component according to any one of claims 12 to 16.

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