Light-weight and robust timepiece component

Abstract

Component, in particular a timepiece component, characterized in that it comprises at least one porous core, comprising a first material or based on a first material, with a density of less than or equal to 80%, or even less than or equal to 60%, or even less than or equal to 50%, of the density of the first solid material, and in that it comprises a surface coating comprising at least one layer with a density greater than the density of the at least one porous core.

Description

[0001] Lightweight and robust watch component

[0002] The present invention relates to a watch component, in particular a watch component for display, or more generally any other component. It also relates to a timepiece, in particular a wristwatch, comprising at least one such watch component. It also relates to a method for manufacturing such a watch component.

[0003] A watch component, and more specifically a watch component for exterior use, must achieve numerous mechanical properties, sometimes contradictory. Among these sought-after properties, we can mention:

[0004] - Lightness, which makes wearing a timepiece comfortable;

[0005] - A very attractive appearance, free from defects, compatible with the aesthetic requirements of luxury watchmaking;

[0006] - Robustness, to withstand the external constraints undergone by a timepiece, so that the watch component retains the same appearance over time, and more generally all of its mechanical properties over time.

[0007] In practice, existing solutions represent compromises between these properties. Generally, watch components are thus produced massively from a material that can be both light and hard. These existing solutions, however, have limitations, and there is a need to identify new solutions that optimize the properties and / or appearance of watch components.

[0008] An object of the present invention is therefore to propose a solution for obtaining a watch component, in particular a watch component for display, which is light and robust, in an improved manner compared to the state of the art. To this end, the invention is based on a watch component for a timepiece comprising a shell comprising a three-dimensional shape delimiting a hollowed-out portion, characterized in that the shell has a porosity rate of less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%, in that the shell is not closed so that its hollowed-out portion is wholly or partly open in an orientation intended for positioning towards the inside of the timepiece, in that it comprises a reinforcing structure extending in all or part of the hollowed-out portion, this reinforcing structure forming a three-dimensional lattice or mesh network, the shell and the reinforcing structure forming a single-piece structure.

[0009] The invention is also based on a method for manufacturing a timepiece component for a timepiece, characterized in that it comprises a step of additive manufacturing of a shell comprising a three-dimensional shape delimiting a hollowed-out portion, the shell having a porosity rate less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%, the shell not being closed so that its hollowed-out portion is wholly or partly open in an orientation intended for positioning towards the inside of the timepiece, and of simultaneous additive manufacturing of a reinforcement structure extending in all or part of the hollowed-out portion, this reinforcement structure forming a lattice or trellis network, in particular a self-supporting network allowing its manufacture by addition of material without the need for sacrificial support elements.

[0010] The invention is more precisely defined by the claims.

[0011] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment given without limitation in relation to the attached figures among which: Figure 1 represents a perspective view of a case middle according to an embodiment of the invention.

[0012] Figure 2 represents a perspective view cut by a vertical plane of the case according to the embodiment of the invention.

[0013] Figure 3 represents a top view cut by a horizontal plane of the case according to the embodiment of the invention.

[0014] Figure 4 represents an enlarged perspective view of details of a reinforcement structure of the middle part according to the embodiment of the invention.

[0015] Figure 5 represents a sectional view passing through a vertical plane of a horn of the case according to the embodiment of the invention.

[0016] Figure 6 represents a side view of a case middle according to a variant of the embodiment of the invention.

[0017] Figure 7 represents a perspective view of a timepiece comprising a case middle according to one embodiment of the invention.

[0018] Figure 8 represents a sectional view through a vertical plane of the timepiece comprising a case middle and a bezel according to one embodiment of the invention.

[0019] Figure 9 represents a partial perspective view of a telescope according to one embodiment of the invention.

[0020] The invention relates to a watch component, in particular a casing component, in particular which can be positioned on the periphery of a timepiece or constitute the periphery of a timepiece, such as a case middle. Such a watch component thus comprises a first part oriented towards the inside of the timepiece, in particular towards the volume comprising the watch movement, and a second part oriented towards the outside, in particular intended to be visible from the outside of the timepiece. We will subsequently use the adjectives "inside" and "outside" as defined above, even for a watch component considered independently of a timepiece, in reference to its intended positioning within a timepiece.

[0021] On the other hand, we will conventionally use the adjective horizontal for any direction positioned in a horizontal plane, considering the definition of a horizontal plane by the plane of the back and / or the crystal of a timepiece, or even the plane tangent to the back and / or the crystal in the case where these elements are not perfectly flat. This horizontal plane thus corresponds to the plane of a timepiece. The adjective "vertical" will be used to designate a direction perpendicular to a horizontal plane. These two adjectives "horizontal" and "vertical" will also be used for a watch component considered outside of a timepiece, in reference to its predetermined positioning within a timepiece. The "height" of a component will be considered relative to the vertical direction.

[0022] In addition, the adjectives "lower" and "upper" will be used in reference to the vertical direction, the bottom of a timepiece being in the lower position of the piece, the crystal being in the upper position of said piece. These two adjectives "lower" and "upper" will also be used for a watch component considered outside of a timepiece, in reference to its predetermined positioning within a timepiece.

[0023] As a note, we will use the expression "based on a material" to designate the fact of comprising mainly said material, in particular at least 50% by weight of said material. In all cases, when a particular material is mentioned, it will be possible to use an alternative embodiment with a different material, based on said particular material, which will not be explicitly recalled. In addition, we will sometimes use the simplified expression "component" to designate a watchmaking component, or even abusively a nearly finalized rough draft of a watchmaking component. The invention will be particularly described in the context of a watchmaking component for exterior use, but it may be implemented for any other watchmaking component. The component may thus be in the form of a case middle, as will be described below, but may also be in the form of a link of a bracelet, or even a plate or a bridge of a watchmaking movement.

[0024] The concept of the invention consists in proposing a watch component whose structure or a rough outline of the structure mainly comprises a shell and a reinforcing structure forming a lattice network (or trellis network), in particular a network comprising an alternation of voids and partitions or reinforcements, in particular partitions or reinforcements which meet or intersect and / or are in contact with each other. In particular, the reinforcing structure may comprise a multitude of closely spaced partitions defining a generally porous structure by small interstices positioned between these partitions, these partitions being in contact with each other and extending throughout the volume of the hollowed-out portion, in particular coming into contact with at least three distinct zones of the inner surface of the shell in the same plane section and / or three zones in distinct planes considering the three-dimensional shape of the shell.In particular, partitions may come into contact with upper and lower surfaces of the shell, and with at least one intermediate surface between these upper and lower surfaces. The shell forms a non-porous surface, forming for example the outer surface of the watch component and delimiting a hollowed-out portion opening towards the interior. The reinforcement structure is housed in the hollowed-out portion of the shell. The reinforcement structure is thus porous and light, but with sufficient mechanical properties to allow the watch component to withstand the mechanical stresses which are exerted during its use. The shell provides the necessary strength, and at the same time makes it possible to achieve a high-quality aesthetic appearance. Figures 1 to 5 illustrate a watch component 1 according to an embodiment of the invention, which is a case middle.The case middle has a generally traditional annular shape, which defines a central volume 11, intended for housing a watch movement. The structure of the case middle is particularly visible in Figure 2. It comprises a shell 2 of three-dimensional shape forming in particular the outer peripheral contour of the case middle. It comprises a substantially vertical, slightly curved outer wall, extended inwards on its two ends, respectively lower and upper, by returns (or edges) in horizontal planes, forming the upper and lower surfaces of the case middle. Advantageously, these returns extend sufficiently inwards to form respectively an upper assembly surface 18, to receive a crystal 9, and a lower assembly surface 17, to receive a back 8. The shell thus has a generally U-shaped (or C-shaped) section.This shape delimits a hollowed-out portion 12 of the case, generally surrounded by the shell 2, and opening towards the interior, that is to say towards the central volume 11. The hollowed-out portion 12 generally has a substantially annular shape. According to an alternative embodiment, the shell could further comprise a rib extending from the vertical outer wall of the shell towards the interior of the hollowed-out portion, in particular at the level of the central part considering the height of this wall. As a further alternative, several ribs could be provided.

[0025] The shell 2 is preferably solid, monobloc, even in one piece, forming a continuous material without boundary. Alternatively, it may comprise the assembly of several distinct parts, assembled together by any mechanical and / or chemical means, such as gluing or welding. For example, the lower assembly surface 17 and / or the upper assembly surface 18 may belong to two distinct parts. Advantageously, the shell 2 may have a porosity rate of less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%. Thus, the shell 2 forms an external surface 19, in particular visible, capable of having an attractive appearance, advantageously a continuous appearance, devoid of porosities.

[0026] The case further comprises a reinforcing structure 10 positioned in the hollowed-out portion of the shell 2. This reinforcing structure is in contact with different walls of the shell 2. It thus forms support elements. The reinforcing structure 10 is designed in particular to withstand the mechanical stresses exerted on the shell 2, in particular the stresses during assembly of the timepiece and / or the stresses during wearing of the timepiece, in particular any shocks.

[0027] The shell 2 and the reinforcement structure 10 actually form a single-piece structure. Thus, there is no physical boundary, no physical discontinuity, between these two sub-elements, the shell and the reinforcement structure being abstractly differentiated by their different form and function. Moreover, the hollowed-out portion of the shell is an abstract consideration defined by abstracting from the reinforcement structure, whereas there is actually no hollowed-out portion in the finalized watch component since there is the presence of the reinforcement structure. The shell and the reinforcement structure cannot be physically separated into two distinct parts.The watch component generally comprises a non-porous shell at least partially surrounding a porous reinforcing structure forming the core of the watch component, i.e. occupying a central volume of the watch component, and opening at least onto the inner surface of the watch component, or alternatively also in certain areas on its outer surface. By "porous reinforcing structure", we mean a reinforcing structure comprising an alternation of voids and partitions. The pores are thus not necessarily microscopic, but can also be macroscopic with respect to the scale of the watch component. These pores advantageously remain sufficiently small so as not to form a hollow portion within the watch component. Even in the case of macroscopic pores, the reinforcing structure appears as a porous element comprising partitions which occupy the hollowed-out portion, advantageously without leaving a hollow portion visible.This porous reinforcement structure thus appears in the form of a lattice or mesh network comprising an alternation of voids and partitions or reinforcements, in particular partitions or reinforcements which intersect.

[0028] According to the embodiment, the reinforcement structure 10 comprises juxtaposed elements 13, advantageously arranged in a homogeneous and repeated organization, forming a three-dimensional lattice network. In the example illustrated, the reinforcement structure 10 comprises first elements 13a here having an ellipsoidal, ovoid, or almond-shaped section. In particular, the first elements 13a each comprise partitions 131a, 132a whose ends meet or intersect, advantageously at the upper and lower surfaces of the shell. The first elements 13a are force-recovery elements which structurally reinforce the caseband or the shell of the caseband in the event of stress, for example during traction of a bracelet strand connected to said caseband, or during the assembly of an element on said caseband, in particular during the driving of a bezel onto said caseband.The reinforcing structure 10 may further comprise second elements 13b acting as spacers, the partitions 131b, 132b, 133b of which intersect and thus form crosses or stars, advantageously arranged inside all or part of the first elements 13a, in which case each partition 131b, 132b, 133b may extend from an inner surface 130a of a first element 13a, these partitions 131b, 132b, 133b intersecting in a central zone 130b of said first element 13a. These elements 13b may in particular absorb impacts or forces that are punctual and / or very localized at the level of the shell of the caseband. Such a reinforcing structure 10 is particularly visible in FIG. 4.

[0029] Thus, according to an advantageous construction, the reinforcement structure 10 may comprise a succession of first elements 13a with the association of a first element 13a and a second element 13b. Such a construction will for example be favored at the flanks of the caseband or at any other surface likely to undergo an impact and / or to come into contact with a blunt element external to the caseband. Naturally, the reinforcement structure 10 may comprise a succession of first elements 13a each associated with a second element 13b. As a variant, it may comprise a succession of first elements 13a devoid of a second element 13b. Such a construction will for example be favored between two neighboring horns of the caseband. The reinforcement structure thus advantageously comprises a regular, non-random, three-dimensional structure, forming a repetitive network.

[0030] The reinforcement structure 10 is thus formed of elements 13, forming elementary parts, defining interstices. Advantageously, in addition to its mechanical function mentioned above, the reinforcement structure 10 therefore also defines interstices, and provides lightness to the watch component. According to an advantageous embodiment, these interstices are also shaped to promote the evacuation of the powder during an additive manufacturing step, which will be specified later. The elements 13a, one section of which has an ellipsoidal, ovoid, or almond-shaped section, further promote this evacuation. In the case of an ellipsoidal shape, the ellipse could have a minor axis of 1 mm and a major axis of 4 mm. Preferably, the partitions 131a and 132a protrude from the shell inwards, in the hollowed-out portion, by a length ha of the order of 2 mm.The partitions 131 b, 132 b, 133 b protrude in the same direction with a length hb of between 0.5 mm and 1 mm, less than ha, which further promotes the evacuation of the powder. More generally, hb <ha, en particulier 1 ,2.hb<ha, voire 2.hb<ha .

[0031] The hollowed-out portion 12 which opens towards the central volume 11 thus helps to evacuate the powder which comes from the interstices of the reinforcement structure 10.

[0032] The structure described above has been described for the annular part of the caseband. Advantageously, it is used throughout the entire volume of the caseband, including in the horns 14 intended for attaching bracelet strands. Thus, Figures 3 and 4 particularly make it possible to represent the structure of the caseband 1 at the horns 14. Advantageously, each horn 14 is therefore also formed of a shell 2 and a reinforcement structure 10 housed in a hollowed-out portion of the horn. This reinforcement structure comprises the repetition of gyroid-shaped elements 15 according to this embodiment. This shape is chosen in particular because of its high strength and its ease and speed of manufacture. These elements also form in particular a network of channels for evacuating the powder at the end of the additive manufacturing step. The reinforcement structure 10 also forms interstices within each horn 14 with dimensions between 0.3 mm et 3 mm.

[0033] More generally, the reinforcement structure may thus have a lattice or mesh network form extending across the majority, or even almost all of, or the entire volume (hollowed out portion) defined by the shell. It forms a skeleton composed of alternating voids and partitions forming a regular or irregular porous network, TPMS, alveolar, cellular, or giroid, Schwartz, or even sphere. The lattice network may in particular comprise partitions which intersect randomly or according to a well-defined periodicity. It may comprise the repetition of one or more juxtaposed elementary elements, in particular in contact with each other to form a continuous, porous structure. It advantageously forms an open porous structure, the pores or interstices communicating with each other.The reinforcement structure thus comprises a multitude of closely spaced partitions defining a generally porous structure by small interstices positioned between these partitions, these partitions being in contact with each other and extending throughout the volume of the hollowed-out portion, in particular coming into contact with at least the substantially vertical surface of the hull and each of the upper and lower surfaces of the hull. Each partition may for example comprise a thickness I (visible in Figure 4) of between 0.1 and 0.5 mm. The thickness I of a partition may depend on its length ha measured in the direction from the outside to the inside, and it advantageously respects I < ha / 5.The shell 2 and the reinforcement structure 10 are made of the same first material comprising at least one metal or metal alloy, in particular a precious alloy or a metal superalloy or a stainless steel or a titanium alloy, in particular comprising one or more elements from among Fe, Mg, Al, Ti, Au, Pd, Pt, Ni, Si, and / or Co. This first material may comprise at least one amorphous or partially amorphous alloy, in particular at least one amorphous or partially amorphous metal alloy. This first material may comprise at least one ceramic, in particular based on alumina or zirconia.

[0034] According to an alternative embodiment, the watch component may comprise several different materials, that is to say that the first aforementioned material is made up of several different materials. For example, the watch component may comprise different materials organized in layers, for example superimposed in the vertical and / or horizontal direction, or even in a diagonal direction, and certain layers may be formed of different materials.

[0035] Naturally, the invention is not limited to the specific geometry of the shell and the reinforcement structure as described above. This two-part architecture concept could be implemented only partially in the volume of the watch component, i.e. not necessarily in the entire volume, contrary to the previous description. In addition, the shell and its hollowed-out portion could have another geometry. For example, the emerging hollowed-out portion (in other words the reinforcement structure) could not extend over the entire inner surface of the watch component, for example not over the entire inner circumference 111 oriented towards the central volume 11 in the case of the case middle described. It advantageously extends over at least 80% of this inner surface or of this inner circumference 111, or even over at least 90%. In addition, the hollowed-out portion may extend over all or part of the watch component.It advantageously extends over at least 75% of the height h of the inner surface of the watch component or of the inner circumference 111 of the watch component, or even over at least 85% of this height h or of the inner circumference 111 of the watch component.

[0036] According to the embodiment, the case also comprises support elements 16, positioned in the hollowed-out portion 12 and projecting into the central volume 11. These support elements 16 act in particular as support structures for receiving and / or positioning and / or fixing a movement or a casing ring.

[0037] Figure 6 represents a variant of the embodiment, in which the caseband comprises positive reliefs 113 on at least a portion of its outer surface 19, i.e. protruding outwardly from the outer surface of the shell 2. Advantageously, these reliefs are visible on a finished timepiece, as represented by Figure 7. Advantageously, these positive reliefs 113 correspond at least partially to the geometries or contours of the elements 13, in particular to all or part of the partitions 131a, 132a, 131b, 132b, 133b, and / or the elements 15 within the horns 14. More generally, these positive reliefs 113 correspond at least partially to the geometries of the reinforcement structure 10. In other words, these positive reliefs form at least partially an extension of the lattice network of the reinforcement structure 10.These reliefs thus evoke the complexity of the lattice network, without compromising the watertightness of the central volume 11 once the back and the glass are assembled on the caseband, in particular by means of sealing gaskets.

[0038] More generally, these positive reliefs 113 can be formed independently of the reinforcing structure 10, and therefore do not necessarily correspond to the reinforcing structure.

[0039] Thus, a watch component may comprise a first lattice network 10 which may be considered as “internal”, as well as a second lattice network which may be considered as “external”, these two lattice networks being separated by a shell. These networks may be homogeneous or inhomogeneous and may in particular comprise porosity gradients.

[0040] According to another embodiment variant, all or part of the outer surface 19 of the shell 2 may be covered by at least one layer of coating. By combining this other variant with the previous variant, it is possible to use the positive reliefs 113 to delimit a network of cavities 110 at the level of the outer surface 19 of the watch component, which form receptacles for receiving such a coating. Preferably, these positive reliefs form projections of the order of 0.1 mm to 2 mm, measured from the outer surface 19 of the shell 2.

[0041] According to an advantageous embodiment, the at least one coating layer has a surface hardness greater than or equal to 500HV, or even greater than or equal to 600HV, or even greater than or equal to 900HV.

[0042] The at least one coating layer may be in a second material, which may be different from the first material. In particular, the first material may have a lower density than the second material.

[0043] For example, according to a first embodiment, the second material may comprise tungsten carbide WC particles, and cobalt-chromium CoCr particles which fulfill the function of binder.

[0044] Such a layer may, for example, have a thickness of around 100 pm to 500 pm. A surface coating with such a layer thus provides the desired robustness and hardness to the watch component, which may be made from a very light and / or ductile first material.

[0045] According to a second embodiment, the coating may have the function of forming a decorative layer. For this, the second material may be a metal or a metal alloy, for example made from at least one element of the Au, Ag, Pt, Pd type. The second material may, for example, form a layer which may, for example, have a thickness of between 500 nm and 20 pm.

[0046] An advantage of such an outer layer is that it allows for the formation of a dense and highly hard surface layer, which meets the high demands of luxury watchmaking. This decorative layer contributes to the overall robustness of the coating, in addition to any other hard layer, while forming an exposed and visible outer surface of the watch component, with an attractive appearance and high hardness.

[0047] According to a third embodiment, the second material may comprise an amorphous or partially amorphous metal. It may for example be a metallic glass or an amorphous or partially amorphous metal alloy comprising a metal base formed from at least one metal among the elements Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr. Such a coating layer may for example have a thickness of between 20 and 500 pm, or even between 70 and 350 pm.

[0048] Such a coating layer comprising a second metallic material that is at least partially amorphous provides advantageous properties to the watch component, including high resistance to corrosion and anti-allergenic properties, while having a high surface hardness, which may be greater than or equal to 500 HV.

[0049] According to a fourth embodiment, the second material may comprise at least one resilient material, to form a coating of which at least one layer is resilient. For this purpose, the resilient material may be a polymer, in particular an elastomer such as a thermoplastic elastomer (TPE) or a fluoroelastomer (FKM, FFKM or FEPM), or a natural rubber (NR) or synthetic rubber (SBR, HNBR, EPDM), or a vinyl methylsilicone (VMQ) or a fluorosilicone (FVMQ). Alternatively, the second material may be a thermosetting elastomer. Such a coating layer comprising a second resilient material has the particular advantage of providing very good impact resistance properties.

[0050] According to a fifth embodiment, the second material may be a composite. It may, for example, be a polymer-ceramic composite material, in particular a composite known in particular by its trade name HyCeram®.

[0051] Naturally, all these coating variants can be combined in the case where they are technically compatible. In particular, a first part of the outer surface 19 of the watch component can be coated with a first coating, while a second part of this outer surface 19 can be coated with a different second coating. Furthermore, the same coating can comprise several distinct layers, for example in different materials. For example, a coating can be formed of a first hard layer and a second layer that is both hard and decorative. A resilient layer can also be formed on the surface of the component, and be covered with a hard layer and / or a layer that is both hard and decorative. In this case, the second material is made of several different materials.

[0052] Advantageously, the at least one coating layer has a porosity rate of less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%. It may have a density greater than or equal to 90%, or even greater than or equal to 99% of the density of the second solid material.

[0053] Finally, the coating may have a thickness of between 500 nm and 500 pm, and may for example form a thin layer with a thickness of between 500 nm and 20 pm, or a thick layer with a thickness greater than 100 pm, or even between 100 pm and 500 pm, or even between 100 pm and 300 pm. According to yet another variant embodiment of the watch component, not shown, a third material may be distributed within the reinforcement structure 10. It may for example be a third resilient material, intended to dissipate shocks and thus best preserve the component. Such a watch component may or may not be coated. This third material may thus fill all or part of the interstices of the lattice network forming the reinforcement structure 10. We will hereinafter call it the filling material.

[0054] The second and third materials mentioned above may advantageously be different from the first material, to meet the different functions mentioned above. However, this is not imperative. In particular, the second material may be identical or belong to the same family as the first material. For example, a titanium case may be manufactured and then coated with a layer of titanium by thermal spraying.

[0055] As a note, the watch component represented by figures 1 to 5 therefore comprises the main structure of the invention, that is to say the shell and the reinforcement structure. It is not necessarily completely finalized, if we consider the variants with a coating or the filling of the reinforcement structure. For simplification, however, we also call such a watch component blank a watch component, the blank already comprising the main structure.

[0056] The invention is particularly suitable for any component, in particular any watch component, in particular any exterior component. This watch component can take various forms. Advantageously, all or part of the watch component 1 extends around a volume intended to receive a watch movement or another timepiece component or intended to equip a timepiece, and has, for example, an annular shape. It can, for example, be a case middle, a bezel, a bezel disc, or a flange. The invention has been described in detail in the case of the production of a case middle, but can therefore be applied to other watch components, for example a bezel, as shown in Figure 9.

[0057] Advantageously, it is possible to assemble different watch components according to the invention in order to propose in particular a light and robust watch case while presenting an attractive appearance, compatible with the aesthetic requirements of luxury watchmaking. For example, such a case could comprise a caseband according to the invention and a bezel and / or a flange according to the invention, as shown in Figures 6 and 7.

[0058] The invention also relates to a timepiece, in particular a wristwatch, which comprises at least one timepiece component as described above.

[0059] Advantageously, the hollowed-out portion 12 and / or the central volume 11 of the timepiece component is protected from the external environment once the components are assembled to form a timepiece. In the case of a case middle, the central volume 11 is watertight once the crystal and the back, as well as any means for actuating the timepiece (such as a crown and / or pushers or correctors), are assembled on the case middle. In the case of a flange, the latter may be assembled within the case middle, the latter being watertight once the crystal and the back are assembled on the case middle. In the case of a bezel disc or a bezel, the hollowed-out portion 12 may face an assembly and / or sealing gasket once the disc or the bezel is assembled on the case middle, such as the sealing gasket 22 shown in FIG. 8.Preferably, the reinforcement structure 10 is durable, that is to say that it retains its integrity during disassembly of the timepiece. In a particular use case, the reinforcement structure 10 may deform, or even fracture, during disassembly of the timepiece.

[0060] The invention also relates to a method for manufacturing a timepiece component for a timepiece, characterized in that it comprises a step of additive manufacturing of a shell 2 comprising a three-dimensional shape delimiting a hollowed-out portion 12, the shell 2 having a porosity rate less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%, the shell 2 not being closed so that its hollowed-out portion 12 is wholly or partly open in an orientation intended for positioning towards the inside of the timepiece. This additive manufacturing step simultaneously manufactures a reinforcing structure 10 extending in all or part of the hollowed-out portion 12, this reinforcing structure 10 forming a lattice network.

[0061] Preferably, this step is implemented by the powder or powder bed laser fusion technique (“Power Bed Fusion” in English), which has the advantage of producing a structure with great precision. Advantageously, the hollowed-out portion 12 facilitates this additive manufacturing step by allowing the evacuation of the powder. For this, it opens onto the interior surface of the watch component. In addition, preferably, its opening surface is large, extends over a significant proportion of the total interior surface of the watch component and / or over a significant height.For this, the hollowed-out portion 12 may extend over at least 80% of the interior surface of the hull, or even over at least 90% of the interior surface of the hull, and / or may extend over at least 75% of the height of the interior surface of the hull, or even over at least 85% of the height of the interior surface of the hull, and may open onto all or almost all of its interior surface.

[0062] Preferably, this lattice network has a shape such that it is self-supporting and allows this fabrication by addition of material without the need for a sacrificial support element. Alternatively, sacrificial support elements may be used.

[0063] Advanced design methods such as numerical simulation and topological optimization (assisted or not by an artificial intelligence model and / or by a machine learning model) can be advantageously used for the definition and dimensioning of the reinforcement structure 10. These methods make it possible to distribute the material only where it is necessary to fulfill the expected functions, in particular to withstand mechanical stresses, which makes it possible to considerably reduce the total mass of the component without compromising its mechanical strength. Thus, according to an advantageous embodiment variant, this reinforcement structure can also be designed to fulfill the additional functions of powder evacuation during manufacturing and self-supporting, as explained previously.To meet these requirements, the reinforcement structure may include the architecture described above, based on juxtaposed elements or, as a variant, may have another architecture.

[0064] Furthermore, the process of obtaining the component, by additive manufacturing, is particularly advantageous because it allows the quantity of material used to be minimized.

[0065] The manufacturing process may include one or more other optional steps, which may be combined and / or carried out in different orders, according to embodiment variants, including:

[0066] - a step of reworking the watch component, so as to obtain the desired surface conditions, in particular at the level of its external surface 19. This may for example be a mechanical reworking step or one using a laser, in particular a femtosecond laser, which makes it possible to obtain a polished surface, or one having a predefined roughness, in particular making it possible to promote the adhesion of a coating;

[0067] - a tribofinishing step which may, for example, include a mechanochemical step of tumbling or trovalization, which may or may not complement the previous step;

[0068] - a step of depositing at least one layer of a surface coating. The various techniques implemented or envisaged are described below. In such a case, the method may implement an additional optional step of reworking the coated watch component. This step may constitute a step of reworking the coating alone, or a step of reworking both the shell of the component and the coating. In the latter case, the watch component resulting from additive manufacturing comprises one or more excess thicknesses in different areas, which are then reworked in this reworking step to achieve a dimensioning of the component;

[0069] - a step of structuring and / or coloring at least one layer of a surface coating. The different techniques implemented or envisaged are described below;

[0070] - a step of filling the interstices formed by the reinforcement structure 10 with a filling material, in particular with a resilient material. In this case, the method may comprise an optional step of taking up the filling material overflowing from the reinforcement structure;

[0071] - at least one cleaning operation aimed at removing all manufacturing residue from both the external surface and the internal surface of the external wall of the case.

[0072] Advantageously, the watch component comprises at least one surface provided to allow the component to be gripped during the manufacturing and / or finishing steps. In the particular construction of the case middle described above, the upper assembly surface 18 of the glass or a surface prefiguring the upper assembly surface 18 of the glass can fulfill this function.

[0073] Concerning the step of depositing at least one layer of a surface coating, a first approach may consist of adding a hard layer, in particular to fulfill a protective function. In this case, the deposition may advantageously be carried out by thermal spraying, in particular at high temperature, which may be greater than or equal to 800°C. Such an embodiment variant, for example, implements the spraying at high temperature, for example at 900°C, of ​​ceramic and / or metal particles, such as for example tungsten carbide WC and cobalt-chromium CoCr particles (the cobalt-chromium CoCr acting, within the coating, as a binder between the WC particles), with WC particles possibly having an average diameter of 40 μm, or even a smaller average diameter. Alternatively, other binders could be considered, such as iron-chromium (Fe-Cr). Alternatively, the layer could be devoid of binders.Thermal projection could, for example, be of the plasma type (known by its acronym "VPS" for the English term "Vacuum Plasma Spraying"), which has many advantages, such as allowing adjustment of the chemistry of the material, and being able to project many different materials, such as ceramics, oxides, metals.

[0074] Alternatively, other spraying or deposition techniques are possible. In particular, anodizing, including electrolytic arc anodizing, can be used. Cold spray is also possible. In the latter case, a cold spray technique is carried out at a temperature below the melting point of the powder and / or below the phase transition temperature (for example, below 900°C), to form said high-hardness layer. This cold spray technique makes it possible to coat temperature-sensitive components and / or deposit powders while preserving their structure. The spraying technique will be adapted to the materials used. In all cases, the coating technique chosen has the advantage of allowing the deposition of a thick coating (from 100 μm to 500 μm).

[0075] Projection therefore makes it possible to obtain a thick layer of a coating, for example formed of tungsten carbide WC and cobalt-chromium CoCr or iron-chromium FeCr. Alternatively, other materials can be used, such as carbides, nitrides and / or oxides of metallic elements such as Ti, Al, Cr, Zr. Thus, projection makes it possible to obtain, for example, a thick layer formed among others of TiN or TiC or TiCN, of Cr2O3, AI2O3, or even of ZrO2. Advantageously, the oxide, carbide, or nitride particles are projected in combination with a binder, in the form of simultaneous projection of powders of different materials, which makes it possible to obtain a layer of a particularly qualitative surface coating. Alternatively, it is also possible to project particles devoid of binder, such as for example metallic particles such as particles of titanium or titanium alloys.Alternatively, a black cermet, such as AI2O3-Ti or AI2O3-Cr, can be used to obtain black, polishable surfaces with a hardness of around 500HV. More commonly, the coating can be a ceramic-metal composite. The properties of the coating material, such as toughness and hardness, can be varied by adjusting the relative ceramic and metal ratios. An advantage of this approach is that the spraying techniques are compatible with many materials.

[0076] The projected particles are moreover advantageously in a semi-pasty state, in the case of thermal projection, to spread out upon impact and form a regular and dense layer. By semi-pasty state is meant a semi-solid or semi-liquid state, as opposed to solid grains (or "cold grains") which would produce an irregular structure, in the case of the aforementioned "cold" projection, which is particularly suitable for materials sensitive to high temperatures. The coating layer obtained can thus be not very rough and compact, with low porosity.

[0077] Alternatively, the coating layer may have the main function of decorating the watch component. In this case, the deposition of the coating layer may, for example, be carried out by a physical vapor deposition (PVD), or chemical vapor deposition (CVD), or atomic layer deposition (ALD) process. It may, for example, be a layer of a metal or a metal alloy, for example of the Au, Ag, Pt, Pd type. This layer may, for example, have a thickness of between 500 nm and 20 pm.

[0078] Alternatively, it may be chosen to deposit an at least partially amorphous metal layer. In this case, the deposition may be carried out by overmolding. The at least partially amorphous metal material may be a metallic glass. In particular, the at least partially amorphous material may be an at least partially amorphous metal alloy comprising a metal base formed from at least one metal among the elements Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr. In particular, the at least partially amorphous metal alloy may be zirconium-based, or titanium-based, or nickel-based, or palladium-based, or platinum-based. According to an alternative embodiment, this deposition comprises a sub-step of forming or overmolding, in particular at high temperature, of the metal alloy in liquid or superplastic form, followed by rapid cooling to obtain the metal alloy in amorphous or essentially amorphous form.Another variation is the superplastic forming technique, which involves heating the metal alloy in amorphous form above its glass transition temperature and below its crystallization temperature, then deforming it under low stress in a mold or impression, then cooling it before crystallization. A zirconium-based alloy, such as Zr55Cu30AI10Ni5, or a Pd-based alloy, such as Pd40Cu30Ni10P20, are suitable alloys, as is any alloy that can be obtained in at least partially amorphous form and has a wide temperature range available for implementing the process (in particular a significant difference between the glass transition temperature Tg and the crystallization temperature Tx, for example the alloy Zr55Cu30AI10Ni5 for which Tg = 409°C and Tx = 494°C, i.e. Tx-Tg = 85°C).In practice, the watch component and the metal alloy in at least partially amorphous form are placed in a mold, then the alloy, which has become viscous, is deformed at the deformation temperature, then the mold and the component comprising the overmolded at least partially amorphous alloy are rapidly cooled, then the watch component is demolded. According to yet another variant, the technique of injecting amorphous metal alloys is used, in particular by injection molding. In this case, the watch component is placed in an injection mold which forms a cavity, the alloy is melted at a temperature above the melting temperature, the liquid alloy is injected into the cavity between the walls of the mold and the component, for example by means of an injection piston, then the component and its alloy are rapidly cooled to allow the latter to become amorphous or partially amorphous, then the component is demolded.The metal alloys suitable for this process variant are preferably chosen from alloys based on zirconium, copper, nickel, iron, palladium, titanium, cobalt or hafnium, such as for example alloys of composition Zr58Cu16Ni13AI10Nb3, Zr41Ti14Cu13Ni10Be22 or Pd43Cu27Ni10P20. Alternatively, any other process suitable for overmolding an amorphous or partially amorphous metal alloy onto a component may be implemented.

[0079] Finally, according to another variant, the coating comprises at least one resilient layer, the deposition of which can be carried out by overmolding. Such a technique is particularly well suited to depositing a polymer, in particular an elastomer such as a thermoplastic elastomer (TPE) or a fluoroelastomer (FKM, FFKM or FEPM), or a natural rubber (NR) or synthetic rubber (SBR, HNBR, EPDM), or a vinyl methylsilicone (VMQ) or a fluorosilicone (FVMQ). More generally, it can be a thermoplastic or thermoset polymer.

[0080] Furthermore, as described above, the method may also comprise a step of structuring and / or coloring at least one layer of a surface coating, this optional step therefore applying in the case of the presence of a coating. The coating may thus be structured and / or colored by laser, in particular by femtosecond laser, in particular in the case of a coating comprising a hard layer provided with or based on a ceramic-metal composite material, in particular based on tungsten carbide and cobalt-chromium, or based on tungsten carbide and iron-chromium. The structuring comprises the creation of reliefs, for example by means of satin finishing, spraying or sandblasting. Such structuring may be carried out downstream of an intermediate step consisting of grinding or polishing or micro-blasting the hard layer of the coating.

[0081] Finally, the at least one coating layer may, for example, have a textured, polished, sandblasted, or satin-finished surface finish. Regarding the optional step of filling the interstices formed by the reinforcement structure 10 with a filling material, this filling material may be resilient, in particular chosen from the resilient materials listed above. This step may include a step of infiltrating the lattice network with the filling material. For this, a step of injection molding a filling material, for example an elastomer, may be implemented, the watch component being previously positioned in a mold. The pressures and temperatures involved are adapted for maximum infiltration, with, for example, a pressure of between 50 and 200 bars and a temperature of between 100°C and 250°C, which also allows crosslinking in the case of an elastomer.Alternatively, any material compatible with a liquid or pasty phase infiltration step can be used, such as an at least partially amorphous metal alloy. For this good implementation, the reinforcing structure forms an open porous structure, that is to say that the interstices that it defines are connected to each other, so as to allow the circulation of the filling material throughout the volume. The reinforcing structure thus comprises, for example, channels. The injection (or more generally the infiltration) of the filling material is advantageously carried out via the inner surface of the reinforcing structure. The infiltration is thus carried out at its emerging surface. Advantageously, the reinforcing structure comprises a non-homogeneous porosity, in particular which varies from the inside to the outside. The porosity can in particular increase from the inner face to the outer face of the reinforcing structure.This embodiment can be achieved by a gradient in the pore size, which increases from the inside to the outside. Such an embodiment can thus promote the good flow of the filling material, from the inside to the outside, ensuring that it advantageously reaches the outer surface of the reinforcement structure, in particular the shell. According to an alternative embodiment, the outer surface of the shell does not cover the entire reinforcement structure, the porous outer surface of which thus becomes visible at the outer surface of the watch component. In the case of the implementation of the filling step with a filling material, the latter therefore reaches the outer surface of the reinforcement structure, until it fills the pores at this outer surface, and becomes visible from the outside of the watch component at this surface, due to the absence of a shell.This process thus creates an aesthetic effect on the outer surface of the watch component with variations between visible surfaces of the watch component constituted by the outer surface of the shell and visible surfaces constituted by the filling material and / or the reinforcing structure. To amplify this effect, materials with very different appearances may be chosen, such as different colors, to particularly differentiate the two materials of the reinforcing structure and its filling material, respectively, on the outer surface of the watch component. Naturally, the terminations of the outer surface of the shell and those of the filling material may also differ. In such an embodiment, the material may for example be an elastomer, in particular an elastomer whose Shore A hardness is greater than 40 in order to allow good resistance to wear.

[0082] Naturally, it is possible to combine the different implementation variants described above.

[0083] Ultimately, the invention therefore makes it possible to combine two major objectives for a component, in particular a watch component for exterior use, which were not previously achieved. It makes it possible to obtain both a lightweight component and a mechanically robust component, while being aesthetically attractive.

Claims

CLAIMS 1. A timepiece component for a timepiece comprising a shell (2) comprising a three-dimensional shape delimiting a hollowed-out portion (12), characterized in that the shell (2) has a porosity rate of less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%, in that the shell (2) is not closed so that its hollowed-out portion (12) is wholly or partly open in an orientation intended for positioning towards the inside of the timepiece, in that it comprises a reinforcing structure (10) extending in all or part of the hollowed-out portion (12), this reinforcing structure (10) forming a lattice or trellis network, the shell (2) and the reinforcing structure (10) forming a single-piece structure.

2. Watch component according to the preceding claim, characterized in that the hollowed-out portion (12) extends over at least 80% of the inner surface of the shell (2), or even over at least 90% of the inner surface of the shell (2), and / or extends over at least 80% of the inner periphery (111) of the shell (2), or even over at least 90% of the inner periphery (111) of the shell (2), and / or extends over at least 75% of the height h of the inner surface of the shell (2), or even over at least 85% of the height h of the inner surface of the shell (2).

3. Watch component for a timepiece according to one of the preceding claims, characterized in that the reinforcement structure (10) has a skeleton shape formed by a regular or irregular porous network, in particular of the lattice, TPMS, alveolar, cellular, or giroid type, and / or in that the reinforcement structure (10) comprises juxtaposed elements, in particular in contact with each other to form a continuous structure, comprising elements having an ellipsoid shape, ovoid, or almond-shaped, possibly filled with spacers, notably star-shaped.

4. A timepiece component for a timepiece according to one of the preceding claims, characterized in that the reinforcing structure (10) comprises a multitude of partitions defining a generally porous structure comprising interstices positioned between these partitions, these partitions being in contact with each other and extending in the volume of the hollowed-out portion (12) by coming into contact with at least three distinct zones of the inner surface of the shell (2) in the same flat section, in particular in contact with upper and lower surfaces of the shell (2) and with at least one intermediate surface between these upper and lower surfaces, and / or by coming into contact with at least three zones in distinct planes considering the three-dimensional shape of the shell.

5. Watch component for a timepiece according to one of the preceding claims, characterized in that the reinforcement structure (10) comprises the repetition of first elements (13a) having an ellipsoidal, ovoid, or almond-shaped section, formed by partitions (131a, 132a) whose upper and lower ends meet or intersect, in particular at the upper and lower surfaces of the shell (2), and optionally second elements (13b) acting as spacers according to a cross or star structure arranged in all or part of said first elements (13a).

6. Watch component for a timepiece according to one of the preceding claims, characterized in that the shell (2) and the reinforcement structure (10) are made of a first material comprising at least one metal or a metal alloy, in particular a precious alloy or a metal superalloy or a stainless steel or a titanium alloy, in particular comprising one or more elements from Fe, Mg, Al, Ti, Au, Pd, Pt, Ni, Si, and / or Co, and / or in that the shell (2) and the reinforcing structure (10) comprise at least one amorphous or partially amorphous alloy, in particular at least one amorphous or partially amorphous metal alloy, and / or in that the shell (2) and the reinforcing structure (10) comprise at least one ceramic, in particular based on alumina or zirconia.

7. Watch component for a timepiece according to one of the preceding claims, characterized in that it comprises at least one coating layer arranged on all or part of the outer surface (19) of the shell (2).

8. Watch component for a timepiece according to the preceding claim, characterized in that the shell (2) and the reinforcement structure (10) are made of a first material, the at least one layer of the surface coating comprising a second material different from the first material, in particular the first material having a lower density than that of the second material.

9. A timepiece component for a timepiece according to claim 7 or 8, characterized in that the at least one coating layer has a surface hardness greater than or equal to 500HV, or even greater than or equal to 600HV, or even greater than or equal to 900HV, and / or in that the at least one coating layer is in a second material and has a porosity rate less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01% and / or a density greater than or equal to 90%, or even greater than or equal to 99% of the density of the second solid material, and / or in that the at least one coating layer is covered by a thin decorative layer, in particular having a thickness of between 500 nm and 20 μm, and / or in that the at least one coating layer has a textured, polished, sandblasted or satin surface finish, and / or in that at least a coating layer has a thickness between 20 pm and 500 pm, or even between 70 pm and 350 pm.

10. A timepiece component for a timepiece according to one of claims 7 to 9, characterized in that the at least one coating layer comprises a second material based on ceramic, or which is an oxide, or which is a metal or a metal alloy, or which is a combination of a ceramic and a metal alloy, in particular based on tungsten carbide and cobalt-chromium, or based on tungsten carbide and iron-chromium, and / or in that the at least one coating layer comprises an amorphous or partially amorphous metallic material, in particular a metallic glass or an amorphous metallic alloy, in particular comprising a metallic base formed from at least one metal among the elements Ni, Cu, Pd, Pt, Fe, Co, Ti, Nb, Zr, and / or in that the at least one coating layer comprises a resilient material, such as a polymer, in particular an elastomer such as a thermoplastic elastomer (TPE) or thermosetting elastomer or a fluoroelastomer (FKM, FFKM or FEPM),or a natural rubber (NR) or synthetic rubber (SBR, HNBR, EPDM), or a vinyl methylsilicone (VMQ) or a fluorosilicone (FVMQ), and / or in that the at least one coating layer comprises a polymer-ceramic composite material., 11. Watch component for a timepiece according to one of the preceding claims, characterized in that it comprises a filling material arranged in all or part of the interstices of the reinforcement structure (10), in particular a resilient material.

12. Watch component for a timepiece according to one of the preceding claims, characterized in that it comprises protruding shapes on the outer surface (19) of the shell (2) corresponding to the shape of the reinforcement structure (10), in particular protrusions of the order of 0.1 mm to 2 mm, these projections optionally defining cavities forming surfaces for receiving at least one layer of coating.

13. Watch component for a timepiece according to one of the preceding claims, characterized in that it comprises support elements (16) arranged in the hollow portion (12) of the shell (2).

14. Watch component for a timepiece according to one of the preceding claims, characterized in that it is a case middle, a bezel disc, or a flange, having a shape defining a central space intended to include a movement or a glass or a dial of the timepiece, in particular an annular shape, the hollowed-out portion opening onto the central space.

15. Watch component for a timepiece according to the preceding claim, characterized in that the hollowed-out portion (12) of the shell (2) has a groove shape, in particular an annular groove shape.

16. Watch component for a timepiece according to one of the preceding claims, characterized in that it is a case middle having horns (14) for fixing at least one bracelet strand and in that the hollowed-out portion (12) and the reinforcement structure (10) extend into the horns (14).

17. Method for manufacturing a watch component for a timepiece, characterized in that it comprises a step of additive manufacturing of a shell (2) comprising a three-dimensional shape delimiting a hollowed-out portion (12), the shell (2) having a porosity rate less than or equal to 0.5%, or even less than or equal to 0.1%, or even less than or equal to 0.05%, or even less than or equal to 0.01%, the shell (2) not being closed so that its hollowed-out portion (12) is wholly or partly open in an orientation intended for positioning towards the inside of the timepiece, and simultaneous additive manufacturing of a reinforcement structure (10) extending in all or part of the hollowed-out portion (12), this reinforcement structure forming a lattice or trellis network, in particular a self-supporting network allowing its manufacture by addition of material without the need for sacrificial support elements.

18. Method for manufacturing a watch component for a timepiece according to the preceding claim, characterized in that it comprises a step of depositing at least one coating layer on all or part of the outer surface (19) of the shell (2), and in that it comprises a step of reworking the at least one coating layer and / or the shell (2), in particular protruding shapes on the outer surface (19) of the shell (2).

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