EP4352573A1

EP4352573A1 - Method for manufacturing a timepiece assembly, and timepiece assembly

Info

Publication number: EP4352573A1
Application number: EP22734544.4A
Authority: EP
Inventors: Florian Calame; Stefano HENIN; Xavier Multone; Benoît VINCENT-FALQUET
Original assignee: Rolex SA
Current assignee: Rolex SA
Priority date: 2021-06-11
Filing date: 2022-06-10
Publication date: 2024-04-17
Also published as: JP2024521262A; WO2022258810A1

Abstract

Timepiece assembly comprising a first timepiece component (10) assembled with a distinct second timepiece component (20), the first timepiece component (10) comprising at least one functional part and a receiving opening (11) that can form a connecting hole distinct from said functional part, the wall delimiting said receiving opening (11) forming a first connecting surface (12), the second timepiece component (20) comprising a second connecting surface (22) and being rigidly assembled with the first timepiece component by direct or indirect contact between the respective first and second connecting surfaces (12, 22) of said first and second timepiece components (10, 20) at a securing surface, characterized in that at least one of the first and second connecting surfaces (12, 22) or a third connecting surface of an optional intermediate third component (30) is made of silicon oxidized by heat treatment so that the first and second timepiece components are rigidly secured to each other by growth of a layer of oxidized silicon.

Description

Process for manufacturing a watch assembly and watch assembly

The present invention relates to a horological assembly of at least two horological components. It also relates to a watch movement and to a timepiece comprising at least one such watch assembly. It also relates to a process for manufacturing such a watch assembly.

Ceramic is increasingly used in watchmaking, for example to form watch axes, because its intrinsic mechanical properties, in particular hardness, and its insensitivity to magnetic fields are very advantageous for many watch components.

Traditional assembly solutions for watch components, designed for metallic materials, are however not always suitable or optimal for ceramics. In addition, silicon is also increasingly used to manufacture watch components, and due to its fragility, traditional assembly solutions for watch components are not always suitable or optimal for silicon.

Thus, the present invention aims to improve watch assemblies, and in particular to define a watch assembly solution particularly suited to the use of ceramics. More specifically, the object of the invention is to define a watch assembly solution that is reliable, durable, easy to implement.

To this end, the invention is based on a timepiece assembly comprising a first timepiece component assembled with a second distinct timepiece component, the first timepiece component comprising a reception opening or connection hole, the wall delimiting said reception opening or connection hole forming a first connecting surface, the second timepiece component comprising a second connection surface and being assembled integrally with the first timepiece component by direct or indirect contact of the respective first and second connection surfaces of the said first and second timepiece components at the level of an attachment surface, characterized in that at least one of the first and second bonding surfaces, or a third bonding surface of an optional third intermediate component, is made of silicon oxidized by heat treatment so that the first and second timepiece components are secured together by growth of a layer of oxidized silicon.

The first timepiece component may comprise at least one functional part and a reception opening separate from said functional part.

According to a first embodiment, the outline of the reception opening of the first timepiece component is closed, and this reception opening or connecting hole may have a constant section over the whole of its first connecting surface.

According to a second embodiment, the contour of the receiving opening opens onto the outer circumference of the first timepiece component and the receiving opening or connecting hole may have a constant section over the whole of its first connecting surface, the height is between a portion of the total thickness and the total thickness of the first timepiece component.

On the other hand, the second timepiece component may have a portion of variable section, in particular which increases continuously from a border with its second connecting surface, this portion of section increasing continuously outside the receiving opening , or connecting hole, in close proximity to one end of said receiving opening.

The invention also relates to a method for manufacturing a timepiece assembly comprising a first timepiece component and a second distinct timepiece component, characterized in that it comprises the following steps: o Assemble said two watch components in an intermediate configuration with less play, so that the second watch component is positioned in a connecting hole or opening for receiving the first watch component, a first connecting surface of the first watch component being positioned opposite -in relation to a second connecting surface of the second timepiece component, optionally via a third inner and outer connecting surface of a third intermediate sleeve-type component, at least one of the first and second surfaces of bond or an optional third inner and outer bonding surface being made of silicon; o Carry out a heat treatment of the watch assembly in its intermediate configuration, so as to obtain the growth of an oxidized silicon layer of the at least one silicon bonding surface, until obtaining a predefined joining of the two components watchmakers.

The invention is more particularly defined by the claims.

These objects, characteristics and advantages of the present invention will be explained in detail in the following description of particular embodiments made on a non-limiting basis in relation to the attached figures, among which:

Figures 1a and 1b show a first step in a watch assembly process according to one embodiment of the invention.

Figures 2a and 2b represent a second step of the watch assembly process according to one embodiment of the invention.

FIG. 3 represents a third step of the watch assembly method according to one embodiment of the invention. FIGS. 4a and 4b represent enlarged views of the third step of the watch assembly method according to one embodiment of the invention.

FIG. 5 represents the evolution of the tightening of the assembly in a fourth step of the watch assembly process according to one embodiment of the invention.

FIG. 6 represents a part of a watch movement comprising watch assemblies according to a first embodiment of the invention.

FIG. 7 represents a part of a watch movement comprising watch assemblies according to a second embodiment of the invention.

FIG. 8 represents a first variant of the third step of the watch assembly method according to one embodiment of the invention.

FIG. 9 represents a second variant of the third step of the watch assembly process according to one embodiment of the invention.

FIG. 10 represents a third variant of the third step of the watch assembly method according to one embodiment of the invention.

FIG. 11 represents a fourth variant of the third step of the watch assembly process according to one embodiment of the invention.

Figures 12 and 13 represent, in enlarged schematic views, the third step and the assembly obtained by implementing the fourth step of the watch assembly method according to the fourth variant of the embodiment of the invention.

FIG. 14 represents a fifth variant of the third step of the watch assembly method according to one embodiment of the invention. Figure 15 shows a balance plate provided with a receiving opening for receiving a plate pin.

Figure 16 shows a plate pin assembled to a balance plate of Figure 15 according to one embodiment of the invention.

Figure 17 shows a balance plate with a receiving opening for receiving a pulse finger.

Figure 18 shows a pulse finger assembled to a balance plate of Figure 17 according to one embodiment of the invention.

Figure 19 shows a jumper with a receiving opening for receiving a jumper beak.

Figure 20 shows a jumper mouthpiece assembled to a jumper of Figure 19 according to one embodiment of the invention.

Figure 21 shows a first component comprising a female part forming an open receiving opening according to another embodiment of the invention.

Figure 22 shows a second component comprising a male part assembled to the first component of Figure 21 according to this other embodiment of the invention.

Figures 23 to 26 show connecting surfaces having grooves according to embodiments of the invention.

The invention advantageously relates to a method of manufacturing a timepiece assembly. The purpose of such a process is to assemble together in an integral manner at least two distinct horological components, to form an integral assembly. which we will call watchmaking assembly. At least one of the horological components of the horological assembly is advantageously predominantly made of ceramic, that is to say it is wholly or partly made of ceramic, and/or advantageously comprises at least 50% by weight of ceramic. The ceramic is advantageously present at the level of the connection surface of said watch component, which is predominantly made of ceramic.

The ceramic may especially be a zirconia, in particular a yttria zirconia, especially a 3% molar yttria zirconia or a 2% molar yttria zirconia, or a monocrystalline or polycrystalline alumina, or an alumina-zirconia combination. Alternatively, the ceramic may be composed of nitride, carbide and/or boride of refractory metals, alone or in combination with each other, as well as in combination with oxides such as the aforementioned zirconia and alumina.

A process for manufacturing a watch assembly will now be described.

A first step of the method according to the embodiment consists in obtaining two distinct horological components, which one wishes to assemble to form an integral assembly.

FIG. 1a thus illustrates a first timepiece component 10, which is a silicon wheel according to the example embodiment. It includes a receiving opening 11 in its central part, also called a “connection hole”, corresponding to a hub of the wheel. According to this embodiment, the receiving opening 11 (connection hole), has a cross section, that is to say perpendicular to its central axis, of circular shape. As a variant, this section could have another shape, for example ellipsoidal, ovoid, polygonal, etc. and/or comprise, along its circumference, at least one groove, the section of which may have any sort of geometries. The at least one groove is provided to facilitate both the growth of the layer of silicon oxide and the pre-assembly of the two timepiece components. The wall delimiting this receiving opening forms a connecting surface 12, as will be specified later. The wheel includes moreover a peripheral part comprising notches or teeth 13, intended to cooperate with another horological assembly within a horological movement. This peripheral part forms a functional part of the first timepiece component 10. Advantageously, this first timepiece component 10 can be made of silicon from a standard silicon wafer, etched by a traditional process of deep reactive ion etching (known by the acronym DRIE in English). In this process, several identical wheels are formed simultaneously on the same silicon wafer.

FIG. 1b illustrates a second timepiece component 20, distinct from the first timepiece component, which is a ceramic axle according to the example embodiment, intended for assembly in the hub of the wheel of FIG. 1a, to allow the rotating arrangement of the wheel within a watch movement. According to this embodiment, the second timepiece component 20 is therefore intended for mounting through the receiving opening 11 (the connection hole) of the first timepiece component 10. To this end, in this embodiment, the second watchmaking component 20 shows a cross section, that is to say perpendicular to its axis of rotation, which is circular. As a variant, this section could have another shape, for example, ellipsoidal, ovoid, polygonal, etc. The two ends 21 of the shaft are intended for mounting within a watch movement allowing the shaft to rotate with less friction. The watch axis can be made of ceramic using a bar and a laser cutting process followed by tribofinishing, which makes it possible to obtain precise geometry and a controlled surface finish. The peripheral surface of the second timepiece component 20 comprises a second connection surface 22, intended for attachment to the first connection surface 12 of the first timepiece component 10 to form the timepiece assembly of the two timepiece components, as will be detailed. Thus, the second timepiece component 20 has a connecting surface 22 of the male type, intended to cooperate with a connection surface 12 of the female type of the first timepiece component 10. FIG. 2a represents an intermediate phase of the second step of the assembly method, in which several second timepiece components 20 are moved closer to a support 40 pierced with blind holes 41 . This support 40 is an intermediate element, used by the manufacturing process on a temporary basis. It is not part of the watch assembly. It comes in any material resistant to the silicon oxidation temperature. Advantageously, it is also made of a material with a coefficient of thermal expansion similar to that of the second timepiece component 20.

Each second timepiece component 20 is inserted into a respective blind hole 41 of the support 40, the diameter of which corresponds to that of the second timepiece component 20, so that the latter is held in a stable and precise manner by the support 40 in the position illustrated by Figure 2b.

FIG. 3 represents a third step of the timepiece assembly method according to the embodiment of the invention, in which a first timepiece component 10 is assembled on each second timepiece component 20. For this, the reception opening 11 (the connection hole) of the first timepiece component 10 is positioned opposite the upper end 21 of the second timepiece component 20, then the first timepiece component 10 is slid downwards along the second timepiece component 20, until to come to rest on the upper surface 42 of the support 40.

FIG. 4a illustrates in an enlarged manner the configuration obtained at the end of the third step, which forms an intermediate assembly configuration of the two timepiece components. The two timepiece components 10, 20 are positioned in their final relative position relative to each other, but are not yet secured together. Indeed, their respective connecting surfaces 12, 22 are facing each other, but separated by a small distance d, as shown in FIG. 4b, which represents a clearance between the two components. At this stage, the two timepiece components therefore do not come into contact with each other. This clearance allows easy relative positioning of the two watch components, while guaranteeing minimal mobility between the two watchmaking components in this non-unitary temporary assembly positioning. Advantageously, the distance d is less than or equal to 4 miti, or even less than or equal to 2 miti. Also advantageously, the distance d is greater than or equal to 1 miti, or even greater than or equal to 1.5 miti. The depth of the blind holes 41 of the support 40 is therefore chosen so that the second connecting surface 22 of the second timepiece component is located just above the upper surface 42 of the support, so as to be able to be located opposite of the first connecting surface 12 of the first timepiece component 10 after the positioning of the latter.

As a side note, as illustrated by FIGS. 2 and 3, the same support 40 advantageously allows the simultaneous manufacture of several timepiece assemblies. This can be particularly advantageous if the first timepiece components 10 are produced by microfabrication from a wafer, in particular a silicon wafer, and these components are still attached to the wafer, for example by fasteners, which makes it possible to produce the assemblies simultaneously for all or part of the components attached to the wafer. Naturally, the invention is not limited to such an embodiment, and also covers an embodiment in which a single watch assembly would be produced.

Next, the watchmaking assembly process implements a fourth step of securing the two watchmaking components. For this, the assembly obtained at the end of the third step is subjected to a heat treatment such that it generates growth of a layer of silicon oxide on the surface of the first timepiece component 10 which is made of silicon. For this, the assembly is advantageously placed in an oxidation furnace, and brought to a temperature of approximately 1100° C., or more generally to any temperature sufficient to generate oxidation of the silicon. Thus, advantageously, this temperature is between 800 and 1200° C., preferably in an oxidizing atmosphere (steam for example). In addition, the treatment time is chosen so as to achieve a sufficient oxidation thickness for the satisfactory attachment of the two timepiece components. Indeed, during the oxidation of the silicon, a layer of oxidized silicon forms on the surface of the first timepiece component, which increases its overall volume, including at the level of its bonding surface, which totally or partially surrounds the second component. watchmaker. Thus, by continuing the operation over a sufficient period, the distance d separating the two respective connecting surfaces between the two timepiece components is filled by the silicon oxide, until sufficient tightness is reached between the two timepiece components at the level direct contact between their two respective connecting surfaces. This phenomenon is illustrated by FIG. 5, the first curve 51 of which illustrates the evolution of the diameter of the receiving opening 11, which in this case is presented as a connecting hole of circular section, over time during this operation. 'oxidation. It appears that this diameter decreases significantly. According to the example represented, this diameter has decreased by 2 μm in 10 hours of treatment, to become equal to the diameter of the second timepiece component 20 at the level of its connecting surface 22, this diameter remaining constant and represented by the second curve 52.

The evolution of the thickness of the silicon oxide layer as a function of time obeys the following law:

Log(e _ox ) = A Log ² (t) + B Log(t ) + C

Where t is the heat treatment time, e ₀ x represents the thickness of the oxidation layer, and A, B, C are constants.

It can thus be seen in FIG. 5 that a treatment lasting 40 hours makes it possible to achieve a reduction in the diameter of the reception opening 11 of 4 μm.

As a side note, the ceramic withstands the silicon oxidation temperature, and is not affected, either in terms of its dimensions or in terms of its properties, by the heat treatment implemented. In addition, the support 40 is made of a material which also supports this heat treatment, to ensure the support of the assembly in a constant manner throughout the heat treatment. The growth of the layer of oxidized silicon at the level of the bonding surface 12 therefore makes it possible to achieve direct tightening between the two respective bonding surfaces 12, 22, which is continued until sufficient joining is achieved, compatible with the constraints which will be undergone by the watch assembly in a watch movement, thus ensuring the maintenance of the two watch components in a durable manner during the operation of the watch assembly. As a side note, in this embodiment, the two connecting surfaces therefore come into contact with each other, at the level of a joining surface, which is cylindrical in shape in this embodiment.

The geometry of the parts will advantageously be chosen to allow sufficient play before the heat treatment, allowing in all cases their assembly with less play, while achieving satisfactory joining in an acceptable time by the heat treatment. For this, an oxidized silicon bonding surface of the watch assembly will advantageously be chosen after heat treatment comprising a layer of oxidized silicon with an average thickness greater than or equal to 1 miti, or even greater than or equal to 1.5 μm and/or less than or equal to 4 pm. Alternatively, the geometry of the parts will be chosen so that there is no contact between the first and second components before the oxidation heat treatment, while achieving satisfactory joining in an acceptable time by the heat treatment of oxidation. In this case, the use of a support 40 is advantageous, as illustrated by figures 2 and 3.

As a side note, it is noteworthy that the wall delimiting the receiving opening 11 (the connection hole) of the first timepiece component 10 is connected to the peripheral functional part of said first timepiece component 10 by a rigid connection in the embodiment described. More specifically, the hub of the wheel is connected by four rigid arms to the functional peripheral part according to the example produced. In other words, the wall of the receiving opening 11 is immobile relative to this functional part. We will call it a link this connection between the receiving opening and the functional part is rigid, and more generally of a timepiece component of the rigid type such a timepiece component. Naturally, this rigid connection can be formed by any other number of rigid arms than the four aforementioned arms, and by any other connecting structure not necessarily in the form of arms.

Such a rigid connection has a significant advantage during the implementation of the watch assembly method of the invention, particularly during the final phase of tightening between them the two connecting surfaces by growth of a layer of oxidized silicon. Indeed, during this growth, a force is exerted on the connecting surfaces in contact: if the wall of the receiving opening (connecting hole) is mounted to move relative to the rest of the first watch component, in particular relative to the part functional, the force exerted during the growth of oxide would be likely to move this wall of the receiving opening (of the connection hole), and thus to be absorbed by this movement, to the detriment of the tightening sought at the level of the surfaces in contact. For this reason, a watch component of the rigid type, within the meaning of the preceding definition, is particularly suitable for the watch assembly according to the invention.

FIG. 6 represents by way of example part of a watch movement comprising several watch assemblies of the rigid type, in the sense described above. This part of the watch movement more precisely forms a regulator device 1, comprising in particular an escapement wheel 2 pivoted about an axis A2, and a blocker 3 comprising a first blocker mobile 3a pivoted about a third axis A3a and a second mobile blocker 3b pivoted around a fourth axis A3b, all three arranged in the same plane P and made of silicon, and assembled to their respective ceramic axes by the watchmaking assembly method according to the invention.

Other watch movement parts can benefit from the watch assembly according to the invention, such as for example: - According to Figures 15 and 16, a balance plate 60 with a plate pin 65, as encountered in Swiss lever escapements. In this embodiment, the balance plate 60, mainly made of silicon, comprises an opening 62 for receiving the plate pin 65. The contour of the receiving opening is closed and its geometry is complementary to that of the plate 65. The plate peg 65, preferably made of monocrystalline or polycrystalline alumina, is introduced with reduced clearance into the balance plate 60, perpendicular to its first face, until the engagement end of the peg plate 65 is flush with the second face of the balance plate 60, parallel to the first face. The two timepiece components being positioned relative to each other, they are then assembled by the timepiece assembly method according to the invention.

- According to figures 17 and 18, a balance plate 70 with an impulse finger 75, like those that can be encountered in other types of escapement than the Swiss lever escapement. In this embodiment, the balance plate 70, the two faces of which delimiting its height are parallel and mostly made of silicon, has an opening 72 for receiving the impulse finger 75. The profile of the receiving opening 72 is open , emerging on the periphery of the balance plate 70. The impulse finger 75, preferably made of monocrystalline or polycrystalline alumina, is engaged with reduced play in the balance plate 70, parallel to the faces of the balance plate 70. When the protruding length of the impulse finger 75 is adjusted, the two timepiece components are assembled by the assembly method according to the invention.

- According to Figures 19 and 20, the conformation comprising a receiving opening 82 with an open outline, such as the opening 72 described above, also lends itself, for example, to the assembly of a jumper beak 85 with a jumper 80, such as those used in date mechanisms for example. FIGS. 21 and 22 illustrate another assembly solution between a first component comprising a female part and a second component comprising a male part, making it possible to confer a seat on the male part projecting over the periphery of the female part. According to this embodiment, the assembly involves, in the first timepiece component 90, a reception opening 92 whose profile is open and does not pass through the thickness of the first timepiece component 90. The depth of the reception opening 92 is limited to a portion, which can reach 40% of the total thickness of the first timepiece component 90, in order to provide a seat 93 for the second timepiece component 95. In this conformation, the reception opening is blind, closed off along the thickness of the first component, so that the second timepiece component 95 does not pass through the first timepiece component 90 right through.

Quite surprisingly, the applicant's studies have shown that the mechanical strength of the assembly increases by splitting the connecting surface 12 intended for guiding the second timepiece component, by inserting at least one groove 110, as illustrated by the figures 17, 18, 19, 20, 23, 24, 25 and 26. The at least one groove 110 is provided for various purposes, such as facilitating both the pre-assembly of watch components, by reducing the contact surface, and the access of oxygen to the bonding surface 12 during the oxidation heat treatment, or even, in particular in the case of a receiving opening whose outline is open, to allow the preservation of the pre-positioning of the watch components after oxidation, avoiding any displacement of the male part induced by the growth of the layer of silicon oxide. The at least one spline 110 can have any kind of geometries, including those making it possible to obtain a succession of convex lobes inside the connection opening, as illustrated by FIG. 25. The at least one spline 110 could also be arranged on the connecting surface 22, as shown in Figure 26. As mentioned above, the section of the receiving opening can be open or closed, blind or through, and have a circular or U-shaped geometry, or another shape, for example ellipsoidal, ovoid, polygonal, etc.

As described above, the invention is particularly suitable for the manufacture of a watch assembly comprising a ceramic axis. In addition, it is particularly suitable for assembling this ceramic axle with a first silicon watch component, in particular a silicon wheel. Indeed, silicon is now increasingly used to manufacture watch components thanks to its very advantageous properties. However, it has the disadvantage of being fragile, in particular brittle, which makes it very difficult to assemble it with another component. The invention is thus particularly advantageous for forming a watch assembly between a first silicon watch component and a second ceramic watch component.

Naturally, as a variant embodiment, the second watch component, in particular a watch pin, could be made of a material other than ceramic, for example of another material that is very hard and resistant to the aforementioned oxidation temperature. Thus, the embodiment described previously, even though specifically adapted to ceramics, could as a variant also be used for a timepiece component presented in a material other than ceramic.

For example, the second component could be made of metal, in particular a metal alloy resistant to the oxidation temperature. This metal can be, without limitation, Ti, Zr, Nb, Mo, Ta, W and their respective alloys.

According to another example, the first and second components could be made of silicon Si. This configuration has the advantages of reducing the oxidation time (the dimensions of the opening for receiving the first component decreasing and that of the body of the second component then increasing simultaneously) and/or to allow working with larger initial clearances.

On the other hand, as explained above, the invention is particularly suitable for producing a watch assembly of two watch components of the rigid type. However, it may still be advantageous to use timepiece components of the flexible type, the expression “flexible type” being opposed to the expression “rigid type”. A second embodiment of the invention is therefore based on a timepiece assembly comprising at least one timepiece component of the flexible type, particularly with elastically movable parts. In particular, the first timepiece component could comprise a wall of the receiving opening (connection hole) connected by an elastically movable connection with the functional part. Such a solution according to the second embodiment would be less advantageous for the realization of the assembly as such, that is to say for the function of fixing between them the two watch components, but would bring an additional advantage of facilitating the temporary assembly in the temporary assembly configuration of FIG. 3 of the two timepiece components. Indeed, thanks to a slight elastic mobility of one or more walls of the receiving opening (of the connection hole) relative to a functional part of the first timepiece component, it is possible to move this wall during the temporary assembly of the two timepiece components, which makes it possible to reduce the play separating their respective connecting surfaces, and therefore to reduce the heat treatment time necessary to achieve their joining.

Such an embodiment based on at least one timepiece component of the flexible type then represents a compromise. This flexibility (very low) will be chosen so as to allow the temporary arrangement of the two timepiece components while limiting the possible displacement of the connecting surfaces to achieve sufficient joining by the growth of the oxidized silicon layer. To this end, FIG. 7 illustrates an alternative embodiment of the regulator device of FIG. 6, comprising the same horological components, which thus retain the same references to facilitate reading, but whose geometry of the wheels is modified to introduce greater flexibility. , by an elastic connection connecting the walls of the connection hole of the wheels, in which a ceramic axle is secured by a timepiece assembly according to the invention, with their respective peripheral functional parts. More precisely, in a privileged manner, said wheels each comprise a central reception opening (said connection hole), delimited by elastic arms. The dimensioning of the elastic arms is defined so as to provide an adequate holding torque for each of the wheels on each of their respective axes.

Naturally, the invention is not limited to the embodiments described above.

To this end, according to a first variant of the first or of the second embodiment, the second timepiece component 20 comprises a bearing surface 23. In the case of an axis, this bearing surface 23 can be formed by a larger diameter portion of the 'axis. FIG. 8 illustrates for this purpose the third step of the method of manufacturing a timepiece assembly according to this embodiment variant. By comparing this embodiment with the corresponding figure 3 of the first embodiment described above, it appears that the main difference comes from the fact that a first timepiece component rests on the bearing surface 23 of a second timepiece component, and no longer on the surface 42 of the support 40. The support 40 still holds at least a second timepiece component, but the depth of its blind holes 41 is reduced, since the connecting surfaces of the two respective timepiece components are positioned spaced apart above the upper surface 42 of the support 40. Naturally, as a variant, any other geometry of the second timepiece component forming a surface for receiving a first timepiece component fulfilling the bearing function could be implemented. The presence of such a bearing can facilitate assembly operations, but is not advantageous for the manufacture of the component, because it involves additional machining operations as well as a larger footprint. As a further remark, the first timepiece component retains the same shape as in the embodiments described above. Its connecting surface remains as simple as possible, cylindrical. For example, preferably, no counterbore is added at its surface resting on the bearing surface 23.

FIG. 9 represents a second embodiment variant of the first or of the second embodiment, in which the temporary assembly of the third step of the horological assembly method is implemented without support, for example directly on a silicon wafer 5 comprising at least one blank of the first timepiece component 10, not completely detached from the wafer 5. In this second variant embodiment, the second timepiece component or components also have a surface 23 which comes to rest on the upper surface 6 of the wafer 5, the latter thus also fulfilling a support function in this configuration. As a side note, during the implementation of this second variant embodiment, the assembly formed in this configuration illustrated by FIG. 9 and resulting from the third step of the method is then oxidized in the fourth step of the method. The wafer 5 as a whole is thus oxidized, its blanks of first timepiece components 10 intended to be detached thus being oxidized in this way before a subsequent step of detachment of each first timepiece component 10, already assembled with its respective second timepiece component 20 . The oxidation of the wafer as a whole is not limited to this mode, but can be carried out in any configuration, in particular the configuration illustrated in FIGS. 3 and/or 4. As in the previous variant, the first timepiece component retains the same shape as in the embodiments described above. Its connecting surface remains as simple as possible, cylindrical. For example, preferably, no counterbore is added at its surface resting on bearing surface 23. As a side note, even if there is also a growth of oxidized silicon at bearing surface 23 forming a contact surface between the two watchmaking components, there is no connection function at the level of this contact surface. Thus, the surface for securing the two components remains the cylindrical surface identical to that of the variants described above.

FIG. 10 illustrates a third embodiment variant, which is likewise compatible with the first and second embodiments of the invention and their various variants. This third embodiment variant differs from all the variants described above in that it uses a third intermediate silicon component, separate from the two watch components to be assembled, whose function is to participate in the watch assembly of said two watch components to be assembled. . This third intermediate component comprises a third connecting zone, comprising on the one hand a third internal connecting surface, intended to come into contact with the second connecting surface of the second timepiece component 20, and on the one hand a third connecting surface exterior, intended to come into contact with the first bonding surface of the first timepiece component 10. During the fourth oxidation step of the assembly process, the third bonding zone of the third intermediate component will oxidize, causing the growth two layers of oxidized silicon, respectively inner and outer, which will respectively come into contact with the first bonding surface of the first timepiece component and with the second bonding surface of the second timepiece component, until the desired joining of the three components. In this third variant embodiment, the two connection surfaces 12, 22 of respectively the two timepiece components 10, 20 are in indirect contact, connected by a continuity of material via the connection zone of the third intermediate component, whereas they are in direct contact in the embodiments described above. According to the example illustrated, the third intermediate component 30 is in the form of a sleeve, arranged around the second timepiece component at its connecting surface on the one hand, and inside the receiving opening (Connection hole) of the first timepiece component, vis-à-vis the first connection surface on the other hand. This third intermediate component is assembled in the intermediate assembly configuration with a clearance vis-à-vis each of the two timepiece components to be assembled. This game features the same dimensions as the clearance mentioned above between the two watch components. In this variant embodiment, the surface for joining the two timepiece components is double, at the level of the exterior and interior surfaces respectively. These two joining surfaces are cylindrical in shape in this case, but could have an open contour, or take shapes, for example ellipsoidal, ovoid, polygonal, etc. and/or be provided with grooves. As a side note, even though there is also a growth of oxidized silicon at the bearing surface 23 forming a contact surface between the two timepiece components, there is no securing function at this contact surface. Thus, the joining surfaces of the two components remain cylindrical, as in the variants described above.

This third embodiment variant is, for example, suitable when neither of the two timepiece components is made of silicon. They can thus for example both be totally or mainly made of ceramic. Alternatively, one of them is mostly ceramic, the other being in another material. According to another example, it can be adapted if the respective connecting surfaces of the two timepiece components to be assembled do not have directly compatible dimensions, the receiving opening (the connecting hole) having for example a diameter that is too large relative to the second watchmaking component to achieve direct assembly between the two watchmaking components.

FIGS. 11 to 14 respectively illustrate a fourth and a fifth alternative embodiment, in which the second timepiece component 20 comprises a variable transverse or radial section 25, that is to say a section whose surface is variable 25, preferably of continuous way. In addition, it is located in the immediate vicinity of the connecting surface 22, as will be specified below. FIGS. 11 to 13 illustrate a fourth variant embodiment, which is similar to the first variant embodiment of FIG. 8, in which the bearing surface 23 is replaced by a variable radial section 25, continuously between a border at the level of the second connecting surface 22 and a larger section. As represented by FIGS. 12 and 13, this variable radial section 25 is presented as a portion of evolving radial section, evolving continuously from a surface of minimum radial section Se1, at the level of the border with the second connecting surface 22 , up to a maximum radial cross-sectional area Se2. In this embodiment, the second timepiece component thus globally comprises a first cylindrical part, with a section surface Se1, and a second cylindrical part, with a larger section surface Se2, these two cylindrical parts being linked together by the portion of variable radial section 25 which is intercalated. Preferably, this aforementioned section variation is linear. As a variant, it could have any other shape. The second connecting surface 22 is located on the first cylindrical part, in the immediate vicinity of the variable radial section 25.

The first timepiece component 10 remains unchanged, comprises a reception opening 11 (a connecting hole). According to the embodiments, this reception opening 11 has a constant section.

FIG. 12 particularly illustrates the advantage of such a construction during the implementation of the third step of the method. During the temporary assembly of the first timepiece component 10 with the second timepiece component 20, the receiving opening 11 (connecting hole) is slid with reduced clearance along the second timepiece component 20, according to a clearance in the ranges of values specified previously with reference to FIG. 4b, until its inlet end comes to rest against the portion of variable radial section 25 of the second timepiece component 20, to reach the intermediate assembly configuration, not secured, such as represented by FIG. 12. The contact thus formed between the two timepiece components is therefore of the linear type. As a side note, the variation in section of the variable radial section portion 25 is such that the maximum section Se2 is greater than the section of the reception opening 11. On the contrary, the minimum section Se1 is such that the reception opening 11 can cooperate with less clearance with this minimum section of the second timepiece component 20, the clearance being that mentioned between the two connecting surfaces 12, 22, as described in the previous variants.

In this intermediate assembly configuration, the assembly is advantageously positioned in a support 40, as in the first variant represented by FIG. 8. This support 40 in particular holds the second watch component(s) 20 in a vertical orientation, so as to keep the line of contact between the two timepiece components in a substantially horizontal plane, perpendicular to the axis of the second timepiece component 20, under the effect of gravity. According to the fourth variant embodiment, the line contact between the two components is of circular shape, but could take on any sort of geometries, or an open outline, and/or have grooves, forming a discontinuous line contact.

FIG. 13 represents the assembly obtained after the implementation of the fourth step, which involves joining together the two timepiece components by a thermal oxidation treatment of the silicon, as described previously. At the end of this fourth step, a silicon oxide layer 15 of uniform thickness e ₀ x is formed on the surface of the silicon component, here the first timepiece component 10. As explained previously, the formation of this layer of silicon oxide is accompanied by an increase in volume, which moves the first bonding surface 12 of the first timepiece component 10 until it comes into contact with the second bonding surface 22 of the second timepiece component 20, so as to induce the connection of the two watch components. As a side note, the uniformity of the thickness of the layer of silicon oxide 15 is also at the origin of a rounding of the edges of the first timepiece component 10 in silicon, schematized by circular arcs in FIG. 13 . According to this variant embodiment, as the layer of silicon oxide develops on the surface of the first timepiece component 10, the section of the reception opening 11 (the connecting hole) decreases, which involves the movement of the first timepiece component 10 relative to the second timepiece component 20. In fact, the linear contact zone rises progressively (in FIG. 12, more generally moves along the axis of the second timepiece component), depending on the reduction of his section. The variable radial section portion 25 of the second timepiece component 20 therefore forms a guide ramp for the relative movement of the first timepiece component during the fourth step, that of oxidation, of the process. This phenomenon continues until the first timepiece component 10, more mainly its line of contact with the second timepiece component 20, reaches the boundary between the variable radial section portion 25 and the second connecting surface 22. At this level , the growth of the layer of silicon oxide no longer causes the displacement of the first timepiece component 10 but finalizes the securing of their two respective connection surfaces 12, 22, according to the final configuration of FIG. 13.

As a side note, the relative movement of the two timepiece components 10, 20 according to this fourth embodiment promotes movement in two directions, an axial direction, as described above, but also a radial direction, which allows the relative recentering of the two components. watchmakers 10, 20 if there has been a possible shift in the intermediate configuration.

Finally, this conformation of the second timepiece component 20 advantageously makes it possible on the one hand to form a means for pre-positioning the first timepiece component 10 and on the other hand to avoid an abrupt variation in section of the second timepiece component 10, harmful in terms of mechanical resistance, in particular if the material used is not very resistant to shocks and/or if the sections involved are small. It also appears that this embodiment is very favorable to obtaining a uniform silicon oxide layer 15, as well as to precise relative positioning of the two timepiece components after heat treatment. These aforementioned advantages are particularly observed with respect to a configuration which uses a bearing surface of the second timepiece component, for example according to FIGS. 8 and 9, and even more so with a configuration combining such a bearing surface with a counterbore which would be arranged at the level of the opening reception 1 1 of the first timepiece component 10. This variant embodiment thus optimizes the reinforcement of the robustness of the method of shrinking by oxidation. An advantage of this variant embodiment involving a line contact before heat treatment stems in particular from the fact of the uniformity of the layer of silicon oxide obtained, as mentioned above, which can be explained by the fact that at With the exception of the contact line, all of the surfaces of the silicon timepiece component remain exposed in the same way to the oxidizing atmosphere prevailing during the heat treatment.

According to one embodiment, the variable radial section portion 25 of the second timepiece component 20 can be produced by a turning operation, in particular if this second timepiece component is entirely or partly made of ceramic, as mentioned above. In addition, this variable radial section 25 may have a linear variation, in which case it has a frustoconical shape. According to one embodiment, it may have an opening angle "a" of the frustoconical portion, which represents a compromise between a small value, which favors the mechanical resistance of the watch component by the absence of sudden variation of its radial section , and therefore the absence of a concentration of stresses in this zone, and a higher value, which favors the relative positioning of the two watchmaking components, due to less sensitivity to manufacturing tolerances, since dimensional deviations of the reception opening 11 of the first timepiece component 10 or of the variable radial section portion 25 of the second timepiece component 20 are compensated by small axial displacements. Advantageously, the angle "a" can be between 10 and 80 degrees, or even between 30 and 60 degrees. The choice of an angle "a" equal to or close to 45 degrees represents for example a good compromise. FIG. 14 represents a fifth embodiment variant, which is similar to the second variant of FIG. 9, in which the bearing surface has been replaced by a variable radial section portion 25, similar to that of the fourth variant described above. . The operation obtained during the oxidation step is similar to that described for the previous variant, and the advantages obtained are likewise very similar.

The invention is not limited to the embodiments described. For example, certain embodiment variants described previously could be combined together to form other embodiment variants.

The invention also relates to a watch assembly as such resulting from the watch assembly process described above. This timepiece assembly therefore comprises a first timepiece component assembled with a second distinct timepiece component, the first timepiece component comprising at least one functional part and a reception opening (connection hole) distinct from said functional part, the wall delimiting said reception opening forming a first connection surface, the second timepiece component comprising a second connection surface and being assembled integrally with the first timepiece component by the direct or indirect contact of the respective first and second connection surfaces of said first and second timepiece components.

We will call indirect contact between said two connecting surfaces a configuration in which one or more other layers of materials, distinct from said two watch components, are interposed between said two connecting surfaces, forming a continuity of material between said two connecting surfaces, which allows the joining of the two watch components.

In all cases, at least one of the first and second bonding surfaces or of a third interior and/or exterior bonding surface of a third optional intermediate component is made of silicon oxidized by heat treatment so that the first and second timepiece components are joined together by growth of a layer of oxidized silicon.

It therefore appears that the surface of oxidized silicon is sufficient by its growth to come into engagement on a corresponding connecting surface, to form sufficient clamping at the level of the connecting surfaces to secure the two timepiece components together. As previously explained, the two watch components are first positioned in an intermediate assembly configuration, before the growth of a layer of oxidized silicon by heat treatment which secures the two watch components in their final position corresponding to their intermediate configuration. 'assembly. Such a watch assembly is therefore different from a watch assembly which could include a component in oxidized silicon, but bonded to another component by a traditional means such as bonding or driving in and not through the intermediary of oxidized silicon. In the latter case, the oxidized silicon would necessarily be deteriorated in a detectable manner, by the presence of defects, by a mechanical connection made subsequently to the oxidation, at the level of the connection between the two components, which would entail the risk of chipping. or cracks in the oxidized silicon layer, in addition to its deformation. On the contrary, with the implementation of the invention, the layer of oxidized silicon remains free of defects at the level of the bonding surface of the watch components, more precisely at the level of their joining surface. On the other hand, with the implementation of the invention, the addition of any other means of fixing the two watch components is not necessary, unlike a traditional solution, even if the invention is not not incompatible with the optional use of a second separate complementary fastening means.

The horological components described above are of the wheel type, such as an escape wheel, or of the pinion type, such as an escape pinion, or can be a balance spiral spring, on the one hand, and a clock axis on the other. go. Naturally, the invention applies more generally to any first “female” type watch component assembled with any second “male” type watch component.

On the other hand, as described above, the invention is particularly suitable for at least one of the watch components made of ceramic, or predominantly made of ceramic. This timepiece component can be the first and/or the second timepiece component. This timepiece component can be the “female” type timepiece component and/or the second “male” type timepiece component.

As a side note, said at least one bonding surface in silicon oxidized by heat treatment or more generally the bonding surface of the female-type timepiece component may completely surround the second male-type timepiece component, or over at least 70% of its periphery, or over at least 40% of its periphery, considering at least one of its sections in a transverse plane, that is to say substantially perpendicular to its axis or to its direction of longitudinal extension.

On the other hand, the mechanical connection between the two components is made over the entire height of the connection surface delimiting the opening for receiving the first watch component. The growth of oxidized silicon is therefore carried out between the two bonding surfaces, that is to say in the transverse direction, as defined above, which is also a radial direction in the case where the second component is present as the shape of an axis. The resulting joining surface between the two watch components extends perpendicular to this transverse or radial growth of oxidized silicon, at the level of the surface of the receiving opening of the female-type component.

Still considering a cross-section (radial) at the connection between the two watch components, the reception opening (connection hole) of the first watch component may have a first circular section and the connecting surface of the second watch component may present a second circular section, the diameter of the first circular section being strictly greater than or equal to the diameter of the second circular section before said oxidation by heat treatment. As a variant, one of the first or second connecting surfaces may have a first circular section, the other having a non-circular section, in particular ovoid or elliptical or polygonal, to allow self-centering of the assembly of said two timepiece components during their positioning in the intermediate assembly configuration. As a further variant, said two first and second sections of respectively the first and second connecting surfaces may have a section of the same non-circular shape, in particular ovoid or elliptical or polygonal. As a further variant, the first and/or second connecting surfaces may have a section of non-continuous shape, and/or constant or not over the height of the reception opening. It emerges that the joining surface or surfaces of the two watch components are preferably cylindrical, even ovoid or elliptical or polygonal, or inscribed in a cylindrical shape when a joining surface is not continuous, even ovoid or elliptical. or polygonal.

The reception opening 11 (connection hole) of the first timepiece component 10 can be a through opening or a blind opening.

The connection surface 12 of the first timepiece component 10, complementary to the connection surface 22 of the second timepiece component 20, can advantageously be divided by the insertion of grooves 110 provided in particular to facilitate the access of oxygen to the surface of link 12 during the oxidation heat treatment.

As a variant, the development of the alternation of guide portions and splines can be made on the connecting surface 22 of the second timepiece component 20, as illustrated by FIG. 26. The bonding surface of a timepiece component from among the first timepiece component and the second timepiece component which is not made of oxidized silicon, but for example of ceramic, can comprise a structuring to make it rougher, or can comprise knurling or splines or keying and/or flat.

The bonding surface of a predominantly ceramic watch component can be treated to make it chemically compatible with silicon oxide.

The second timepiece component may include a support bearing.

As a variant, the second component may have a portion of variable section, in particular which increases continuously from a border with its second connecting surface, this portion of section which increases continuously being thus positioned outside the opening of reception of the first timepiece component, in close proximity to one end of said reception opening. This portion of variable section has been described in more detail in the variant embodiments with reference to FIGS. 11 to 14.

Said oxidized silicon bonding surface may comprise an average thickness greater than or equal to 1 miti, or even greater than or equal to 1.5 μm. It may comprise an average thickness less than or equal to 4 μm. The invention also relates to a watch movement which comprises one or more watch assemblies as described above.

The invention also relates to a timepiece, which comprises at least one timepiece assembly as described previously or such a timepiece movement.

Claims

Timepiece assembly comprising a first timepiece component (10) assembled with a second separate timepiece component (20), the first timepiece component (10) comprising a reception opening (11) or connecting hole, the wall delimiting the said reception opening (11 ) or said connection hole forming a first connection surface (12), the second timepiece component (20) comprising a second connection surface (22) and being assembled integrally with the first timepiece component by direct or indirect contact of the first and second connection surfaces (12, 22) respectively of said first and second timepiece components (10, 20) at the level of a connection surface, characterized in that at least one of the first and second connection surfaces (12, 22 ), or a third bonding surface of an optional third intermediate component (30), is made of silicon oxidized by heat treatment so that the first and second timepiece components are solidar ized between them by growth of a layer of oxidized silicon.

Timepiece assembly according to the preceding claim, characterized in that the reception opening (11) of the first timepiece component (10) has a constant section over the whole of its first connecting surface (12).

Timepiece assembly according to one of the preceding claims, characterized in that the second timepiece component has a portion of variable radial section (25) which increases continuously from a border with its second connecting surface (22), this portion of variable radial section (25) thus being positioned outside the receiving opening (11), in close proximity to one end of said receiving opening (11).

4. Watch assembly according to one of the preceding claims, characterized in that at least one of said first and second watch components (10, 20) is predominantly ceramic. 5. Timepiece assembly according to one of the preceding claims, characterized in that the surface(s) for joining said first and second timepiece components (10, 20) is or are cylindrical in shape, even ovoid or elliptical or polygonal, or inscribed ( s) in a cylindrical, even ovoid or elliptical or polygonal shape.

6. Timepiece assembly according to one of the preceding claims, characterized in that at least one of said first and second timepiece components (10, 20) is mainly made of silicon and in that the first connecting surface (12) of the first component watchmaker (10) and the second bonding surface (22) of the second watchmaker component (20) are in direct contact, the bonding surface of said component mainly made of silicon being made of silicon oxidized by heat treatment.

7. Timepiece assembly according to one of claims 1 or 2, characterized in that it comprises a third intermediate component (30) mainly made of silicon, of the sleeve type, comprising a connection zone forming a third external connection surface and a third internal bonding surface in silicon oxidized by heat treatment, the third internal bonding surface being in direct contact with the second bonding surface (22) of the second timepiece component (20) and the third external bonding surface being in direct contact with the first connecting surface (12) of the first timepiece component (10).

8. Timepiece assembly according to one of the preceding claims, characterized in that the first timepiece component (10) comprises at least one functional part, distinct from the reception opening (11), and in that the wall delimiting the receiving opening (11) of the first timepiece component (10) is connected to said functional part of said first timepiece component (10) by a rigid connection so as to remain substantially immobile relative to this functional part, or in that the wall delimiting the opening for receiving the first timepiece component is connected to the functional part by a flexible connection, in particular mobile elastically.

9. Timepiece assembly according to one of the preceding claims, characterized in that the joining surface of said first and second timepiece components (10, 20) completely surrounds, or over at least 70% of its periphery, or over at least 40% from its periphery, the second timepiece component (20).

10. Watch assembly according to one of the preceding claims, characterized in that said first and second watch components (10, 20) have geometries such that their assembly takes place with less play before the oxidation of at least one of the surfaces. bonding silicon by heat treatment.

11. Timepiece assembly according to the preceding claim, characterized in that said reception opening (11) of the first timepiece component (10) has a first circular section, in that said connecting surface (22) of the second timepiece component (20) has a second circular section, the diameter of the first circular section being strictly greater than the diameter of the second circular section before said oxidation by heat treatment, or in that one of the first or second connecting surfaces has a circular section, the the other having a non-circular section, in particular ovoid or elliptical or polygonal, to allow self-centering of the assembly of said two components, or in that said two first and second sections of respectively the first and second connecting surfaces (12, 22 ) have a section of the same non-circular shape, in particular ovoid or elliptical or polygonal.

12. Timepiece assembly according to one of the preceding claims, characterized in that the reception opening (11) of the first timepiece component (10) is through or blind.

13. Timepiece assembly according to one of the preceding claims, characterized in that it comprises at least one connecting surface (12, 22) of a timepiece component from among the first timepiece component (10) and the second timepiece component (20 ) which comprises a structuring to make it rougher, or comprises knurling or splines or keying and/or a flat, and/or in that the second timepiece component (20) comprises a bearing surface (23).

14. Watch assembly according to one of the preceding claims, characterized in that said oxidized silicon bonding surface comprises an oxide layer with an average thickness greater than or equal to 1 miti, or even greater than or equal to 1.5 μm and/or less than or equal to 4 pm.

15. Timepiece assembly according to one of the preceding claims, characterized in that the second timepiece component (20) is an axis, which allows the rotational mounting of the timepiece assembly within a timepiece movement.

16. Timepiece assembly according to one of the preceding claims, characterized in that the first timepiece component (10) is a wheel, such as an escapement wheel, or a pinion, such as an escapement pinion, or a spiral spring of pendulum.

17. Timepiece movement, characterized in that it comprises at least one timepiece assembly according to one of the preceding claims.

18. Timepiece, characterized in that it comprises at least one timepiece assembly according to one of claims 1 to 16 or a timepiece movement according to the preceding claim.

19. A method of manufacturing a watch assembly comprising a first watch component (10) and a second separate watch component (20), characterized in that it comprises the following steps: o Assemble in an intermediate configuration with less clearance said two timepiece components (10, 20), so that the second timepiece component (20) is positioned in a receiving opening (11) or connection hole of the first timepiece component (10), a first connection surface (12) of the first timepiece component (10) being positioned opposite a second connecting surface (22) of the second timepiece component (20), optionally via a third interior and exterior connection surface of a third intermediate component (30) of the sleeve type, at least one of the first and second bonding surfaces (12, 22) or an optional third inner and outer bonding surface being made of silicon; o Carry out a heat treatment of the watch assembly in its intermediate configuration, so as to obtain the growth of an oxidized silicon layer of the at least one silicon bonding surface, until obtaining a predefined joining of the two components watchmakers (10, 20).

20. A method of manufacturing a timepiece assembly according to the preceding claim, characterized in that the intermediate configuration is such that a radial clearance between said two timepiece components (10, 20) is less than or equal to 2 miti, or even less than or equal to 1.5 miti, and/or in that: the second timepiece component (20) is inserted and held in the opening (41) of a support (40) resistant to the temperature of the heat treatment so as to hold it; Where • several second timepiece components (20) are assembled to several blanks of first timepiece components (10) respectively bonded together temporarily on a wafer (5) used in their manufacture.

21. A method of manufacturing a timepiece assembly according to claim 19 or 20, characterized in that in the intermediate configuration, one end of the reception opening (11) of the first timepiece component (10) is in line support, continuous or discontinuous, on a portion of variable radial section of the second timepiece component (10).

22. A method of manufacturing a watch assembly according to one of claims 19 to 21, characterized in that the heat treatment is carried out at a temperature between 800 and 1200°C.