Manufacturing method for watch bearings

Abstract

A method for manufacturing a tenon bearing (1) for pivoting a watch part (2), in particular a tenon stone, comprising: Drilling (E1) of a hole (10a) in the blank (1a) of the bearing (1) along the axis (A1) about which the watch part (2) is intended to rotate, the hole (10a) forming the start (13a) of the first rotation section (13) of the bearing (1), Laser engraving (E2) into the blank (1a), in particular using a femtosecond laser, of a second clearance area (14) of the bearing (1) adjacent to the beginning (13a) of the first pivoting area (13), the second clearance area (14) of the bearing (1) opening onto the first face (11a) of the blank (1a) of the bearing (1), and then The method comprises the steps of removing material by abrasion (E3), in particular by olive cutting, in the first swivel area (13) of the bearing (1) and in the boundary area (14a) between the start (13a) of the first swivel area (13) of the bearing (1) and the second clearance area (14) of the bearing (1), for forming a first swivel area (13) and a second clearance area (14) of the bearing (1) that are adjacent and connected to each other by a chamfered connection.

Description

[Technical field]

[0001] The present invention relates to a method for the manufacture of a tenon bearing for the pivoting of a watch part, in particular the manufacture of a tenon stone. The invention also relates to a tenon bearing obtained by said method, to an assembly including such a bearing and to a movement including such a bearing or such an assembly. The invention finally relates to a watch, in particular a miniature watch, including such a movement or such an assembly or such a bearing. [Background technology]

[0002] The regularity of the rotation of the shafts, especially of the balance shaft type in the shock device, is a major factor in the chronometric performance of a watch. Indeed, any variations over time, such as the wear of the tenons or their degradation due to shocks, cause alterations in the behavior of the oscillator that can induce fluctuations in the operation of the watch.

[0003] There are several shapes of perforated stones (also known as bearings) available on the market, sold by stone suppliers, which are identified in particular by the following phrases: flat stone with olive or cylindrical hole, supporting stone with olive or cylindrical hole, semi-flat stone with olive or cylindrical hole, flat stone with olive or cylindrical hole and two recesses, dome-shaped stone with olive or cylindrical hole.

[0004] These stones are assembled into an integral frame and shock-resistant structure.

[0005] The stones comprise a hole, which may or may not be cut in an olive shape, allowing the pivoting of the tenon on the shaft relative to the tenon surface. Of particular relevance to stones assembled in an integral sill or impact device, the hole usually comprises a recess on a first face of the stone, on the lead-in side of the tenon, intended to facilitate the insertion of the tenon. These stones therefore comprise a first, usually flat, face containing the recess, and a flat or dome-shaped face opposite the recess. In prior art stones, the distinction between the recess and the pivoting area or surface is easily made, the two parts being usually separated by an unserrated edge. Said unserrated edge can prove problematic during the tenon insertion stage, since the tenon abuts against the edge and this contact can leave a mark.

[0006] As disclosed in Patent Document 1 or Patent Document 2, it is known to obtain ceramic sintered stones using a pressing technique.

[0007] From DE 10 200 03 133 A1 a bearing geometry is known which comprises a substantially spherical opening forming a first functional element and having a cross section with a maximum diameter substantially 4.5 times larger than the minimum diameter of the bore, and a substantially conical opening forming a second functional element and having a cross section with a maximum diameter substantially twice the minimum diameter of the bore. The olive shape at the level of the bore is intended to minimize contact with the tenon and to simplify any lubrication.

[0008] From the patent DE 10 200 03 133 A1 a perforated stone shape is known, which comprises a functional element forming the fastening cone of the perforated stone. The shape of said functional element addresses the need for easy mounting of tenon blind holes, especially in shock-resistant devices. Nevertheless, this type of sintered stone is opaque, unlike ruby ​​stones, which have transparency.

[0009] It is clear that existing methods for manufacturing tenon bearings are not optimized and / or do not allow the production of all shapes and / or all materials that may be envisaged for this type of bearing. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] European Patent Application Publication No. 2778801 [Patent Document 2] European Patent Application Publication No. 3483665 Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention is to provide a solution which makes it possible to optimize the production of tenon bearings and to remedy the drawbacks of the prior art. [Means for solving the problem]

[0012] The invention therefore relates to a method for manufacturing a tenon bearing for pivoting a timepiece component, in particular a tenon stone, comprising: Drilling a hole in the bearing blank along the axis about which the watch part is intended to rotate, said hole forming the start of a first rotation section of said bearing, then laser engraving of the blank, in particular with a femtosecond laser, of a second clearance area of ​​the bearing adjacent to the start of the first pivoting area and opening onto a first face of the bearing blank, after which removal of material by abrasion, in particular by olive cutting, at the beginning of the first pivoting section of the bearing and at the boundary section between the beginning of the first pivoting section of the bearing and the second clearance section of the bearing, for the formation of a first pivoting section and a second clearance section of the bearing which are adjacent and connected to each other by a chamfered connection; The method is based on the method comprising the steps of:

[0013] The step of drilling a hole may include a sub-step including obtaining a blank disposed between a first plane and an opposing second plane, and then a sub-step including drilling a through hole in a direction perpendicular to the first plane.

[0014] The step including laser engraving the second gap area of ​​the bearing may include a plurality of successive sub-steps, each sub-step including engraving the bearing blank in at least one plane distinct from the engraving of the preceding sub-step.

[0015] The distinct planes of the various successive sub-steps may be mutually parallel planes substantially parallel to the first surface of the blank and may overlap each other extending between the first surface of the blank and an intermediate plane located within the thickness of the bearing blank.

[0016] Each sub-step of the step including laser engraving may include performing engraving in a new separate plane circumscribing a circular contour centered on the axis of the hole, the diameter of which decreases between the top surface and the mid-plane, such that the step including laser engraving creates a second gap area formed by engraving overlapping circular plates in separate planes, and the engraving diameter at the mid-plane may be substantially equal to the diameter of the hole.

[0017] The distance between two consecutive ones of the distinct planes may be less than or equal to 2 μm, or less than or equal to 1 μm.

[0018] The step of laser engraving the second clearance area of ​​the bearing comprises: the second clearance area forms a continuous, endless extension or expansion from the first pivot area of ​​the bearing to the first surface of the bearing; The second gap area has a substantially frustoconical shape, in the form of a truncated cone, of a straight or curved surface, in particular with a radius of curvature going to infinity in the vicinity of the first surface, The maximum diameter of the second clearance region is greater than four times, or greater than seven times, the minimum diameter of the first turning region; The maximum cross-sectional area of ​​the second gap region is greater than 10 times, 25 times, 30 times, or 50 times the minimum cross-sectional area of ​​the first turning region; a first volume limited by the first swivel area and two planes perpendicular to the axis and passing through the ends of the first swivel area relative to the axis is less than 0.4 times, 0.35 times, 0.3 times, or 0.25 times the second volume limited by the second clearance area and two planes perpendicular to the axis and passing through the ends of the second clearance area relative to the axis; and / or a first volume limited by the first swivel area and two planes perpendicular to the axis and passing through the ends of the first swivel area relative to the axis is greater than 0.1 times, 0.15 times, or 0.2 times the second volume limited by the second clearance area and two planes perpendicular to the axis and passing through the ends of the second clearance area relative to the axis. A curve at an intersection of a plane passing through the axis and perpendicular to the surface and the second gap area is convex. Engraving of the surface having some or all of the features of may be performed.

[0019] The step involving removal of material using abrasion may use a diamond thread.

[0020] The steps including drilling holes in the bearing blank may utilize a broaching tool or a laser.

[0021] The step of drilling a hole in a bearing blank may include an enlargement sub-step including providing the hole with a diameter substantially equal to the minimum diameter of the first pivot area of ​​the bearing.

[0022] A method of manufacturing a bearing may include the step of turning the outer diameter of the bearing.

[0023] The manufacturing method of a bearing may include a buffing or polishing step to reduce said roughness especially in said second clearance area of ​​said bearing.

[0024] The method of manufacturing a bearing may include a step including rolling a second surface of the blank opposite the first surface to form a dome-shaped second surface of the bearing and optionally to form a third clearance area in an enlarged portion of the bore of the blank at the level of the second surface.

[0025] The method for manufacturing a bearing may comprise a step of texturing, in particular with a femtosecond laser, part or all of the second gap area and / or part or all of the third gap area, so that the first pivot area has a roughness different to that of the second gap area and / or so that the first pivot area has an oleophilic surface and the second gap area has, in all or part, an oleophobic surface.

[0026] The blank may be made of a ceramic such as synthetic ruby ​​or polycrystalline corundum, or zirconia, especially yttria-zirconia, or monocrystalline alumina, or an alumina-zirconia bond.

[0027] The invention also relates to a tenon bearing for the pivoting of a timepiece, in particular of a tenon stone, said bearing comprising a hole aligned with the axis for the pivoting of said timepiece, and comprising at least a first pivoting section of the timepiece part; a second clearance region extending from the first face of the bearing to the first pivot region; having The first surface is adapted to be oriented perpendicular or substantially perpendicular to the axis and towards the watch part, and the first pivot area and the second gap area are connected to each other with a chamfered connection (rounded connection).

[0028] The maximum diameter of the second clearance region may be more than four or seven times the minimum diameter of the turning region.

[0029] The maximum cross-sectional area of ​​the second clearance region may be greater than 10 times, or 25 times, or 30 times, or 50 times greater than the minimum cross-sectional area of ​​the first turn region.

[0030] A first volume limited by the first pivot area and two planes perpendicular to the axis and passing through the end of the first pivot area relative to the axis may be less than 0.4, 0.35, 0.3 or 0.25 times the second volume limited by the second clearance area and two planes perpendicular to the axis and passing through the end of the second clearance area relative to the axis, and / or a first volume limited by the first pivot area and two planes perpendicular to the axis and passing through the end of the first pivot area relative to the axis may be greater than 0.1, 0.15 or 0.2 times the second volume limited by the second clearance area and two planes perpendicular to the axis and passing through the end of the second clearance area relative to the axis.

[0031] The second interstitial region may have a frustoconical or generally frustoconical shape.

[0032] The second gap area may be such that a curve at an intersection of the second gap area with a plane passing through the axis is convex.

[0033] The first pivot section may be cut into an olive shape.

[0034] The first pivot region may have a different roughness than the second interstitial region, and / or the first pivot region may have an oleophilic surface and the second interstitial region may have, in whole or in part, an oleophobic surface.

[0035] The invention also relates to an assembly including a bearing as described above, in particular a base or a plate or a bearing or an anti-shock device.

[0036] The invention also relates to a clock movement including a bearing as described above.

[0037] The invention also relates to a timepiece, in particular a miniature timepiece, in particular a wristwatch, comprising a bearing as described above.

[0038] The invention is more particularly defined by the claims.

[0039] The objects, features and advantages of the present invention will be explained in detail in the following non-limiting description of certain specific embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic diagram of a first embodiment of a timepiece including an embodiment of a bearing according to the invention. [Diagram 2] FIG. 2 is a schematic diagram of a first watch embodiment, further comprising watch parts pivoted in bearings. [Diagram 3] FIG. 3 illustrates steps of a method for manufacturing a tenon bearing according to one embodiment of the present invention. [Figure 4] FIG. 4 illustrates steps of a method for manufacturing a tenon bearing according to one embodiment of the present invention. [Diagram 5] FIG. 5 illustrates steps of a method for manufacturing a tenon bearing according to one embodiment of the present invention. [Figure 6] FIG. 6 illustrates steps of a method for manufacturing a tenon bearing according to one embodiment of the present invention. [Figure 7] FIG. 7 illustrates steps of a method for manufacturing a tenon bearing according to one embodiment of the present invention. [Figure 8] FIG. 8 illustrates generally a flow chart of a method, according to an embodiment of the present invention, for manufacturing a tenon bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] An embodiment of a timepiece 300 according to the invention will now be described with reference to figures 1 and 2. Timepiece 300 is a small timepiece, for example a wristwatch.

[0042] The watch includes a watch movement 200. The watch movement 200 is, for example, a mechanical movement, in particular an automatic movement. Alternatively, the movement may be an electronic movement.

[0043] The clock movement 200 comprises an assembly 100, which includes a tenon bearing 1, in the following simply called bearing 1. The bearing makes it possible to guide a clock part 2 in rotation or pivoting. To this end, the bearing allows the reception and guiding of a tenon of the clock part relative to the axis A1. The part preferably includes at least the shaft itself, which includes the tenon.

[0044] In the case of bearings having a hole and a mating recess or cone, the hole may be defined as that part of the stone against which the tenon abuts as it pivots in normal operation, so that the diameter of the hole corresponds substantially to the diameter of the tenon, ignoring tolerances and clearances.

[0045] For example, the timepiece part is the balance assembly of an oscillator of the balance wheel-hairspring type. "Balance assembly" means an assembly consisting of a balance wheel and a shaft, the balance wheel being mounted on the shaft and fixed thereto, in particular by hammering.

[0046] For example, the assembly 100 may include a watch shock-proof device. This type of shock-proof device may include a case, a bearing 1, a jewel, and a spring. In this case, the bearing is a tenon or mortise-stone type bearing. Alternatively, the assembly 100 may include a bridge, such as a plate, or a balance bridge, into which the bearing 1 is fixed by hammering.

[0047] The bearing 1 comprises a bore 10 aligned with the axis A1 for the pivoting of the watch part 2 relative to the axis A1, which is thus the pivot axis of the watch part 2.

[0048] The bearing 1, and in particular the bore 10, has at least - a first pivot area or face 13 of the watch part 2, a second clearance area or surface 14 extending from the first face 11 of the bearing to the first pivot area 13; will be established.

[0049] The first face 11 is perpendicular or substantially perpendicular to the axis A1 and is intended to be oriented towards the watch part 2.

[0050] The first pivot region 13 and the second gap region 14 are connected to each other without an end or by a chamfered connection.

[0051] The bearing is preferably a stone or gemstone. The stone is preferably made of synthetic ruby, i.e. polycrystalline corundum. Alternatively, the stone may be made of other ceramics such as zirconia, especially yttria-zirconia, or monocrystalline alumina, or an alumina-zirconia bond.

[0052] The bearing preferably includes a third clearance area or surface 15 that extends from the second face 12 to the first pivot area 13 of the bearing.

[0053] The second surface 12 of the bearing is the opposite surface to the first surface 11. The first and second surfaces are parallel or substantially parallel. Each is perpendicular or substantially perpendicular to the axis A1. In the illustrated embodiment, the first surface is planar and the second surface is dome-shaped (protruding). Alternatively, the first surface may be dome-shaped. Alternatively, the second surface may be planar.

[0054] The second clearance area is the area in which the watch part 2, and in particular the tenon of the watch part 2, engages in the bearing.

[0055] The third clearance area 15 is an area opposite the second clearance area with respect to the first pivot area and is an area through which the watch part 2, in particular the tenon of the watch part 2, can protrude when placed in the bearing.

[0056] The bearing preferably has a shape of rotation about the axis A1. In particular, the bore has a shape of rotation about the axis A1. Alternatively, only the first pivot area of ​​the bore may have a shape of rotation about the axis A1. As a further alternative, only the first pivot area and the second clearance area of ​​the bore may have a shape of rotation about the axis A1, or only the first pivot area and the third clearance area of ​​the bore may have a shape of rotation about the axis A1.

[0057] The first turning section 13 is advantageously cut in the shape of an olive.

[0058] As mentioned above, there is no visually perceptible demarcation, such as an edge or a vertex, between the first pivot zone 13 and the second clearance zone 14. In fact, the bearing walls or surfaces defining these zones are connected to each other by a chamfered connection or are connected to each other without forming an edge. For this reason, the direction of a plane tangent to the surface of the hole evolves without discontinuities or abrupt changes in direction when the plane is moved within the hole onto the first pivot zone or onto the second clearance zone. In particular, the direction of a plane tangent to the surface of the hole evolves without discontinuities or abrupt changes in direction when the plane is moved within the hole from any point of the first pivot zone to any point of the second clearance zone. In other words, the curve of intersection of a plane passing through the axis A1 and perpendicular to the bearing surface (11) defining the walls of the first pivot zone and the second clearance zone does not feature any corner points at the intersection between the first pivot zone and the second clearance zone or does not feature any corner points throughout their extent. At the intersection of the first turning area and the second gap area, the minimum radius of curvature of the surface or wall of the hole 10, or the minimum radius of curvature of the chamfered connection, is preferably greater than 0.05 mm. The minimum radius of curvature of the surface of the first turning area is more preferably greater than 0.05 mm.

[0059] A portion of the chamfered connection forms part of the first pivot area and another portion of the chamfered connection forms part of the second gap area.

[0060] The boundary between the first pivot area and the second clearance area is, for example, such that the diameter of the hole (measured perpendicular to the axis A1) is greater than or equal to the minimum diameter d of the first pivot area or hole 10 (measured perpendicular to the axis A1). t1.1 times the minimum cross-sectional area (measured perpendicular to axis A1) of the first pivot area or hole 10. Said boundary is referenced 16 in FIG. 1. As a further alternative, the boundary between the first pivot area and the second clearance area is defined as the location where the diameter of the hole is equal to 140% of the nominal diameter of the tenon mid-height (with the shaft including the tenon at rest). Here, "tenon" means the portion of the shaft rotation provided solely for pivoting the shaft in the bearing.

[0061] The second gap area has a widened shape. The second gap area forms a widening or extension from the first pivot area to the first face 11. The second gap area 14 preferably has a frustoconical or substantially frustoconical shape. The second gap area preferably comprises a curved surface with a radius of curvature that tends to infinity. In a complementary manner, the second gap area may also have a cross section with a frustoconical or substantially frustoconical shape. Alternatively, the second gap area may have a cross section with a frustoconical or substantially frustoconical shape. The shape of the second gap area makes it possible to maximize the distance of the watch part from the bearing outside the first pivot area and to simplify the return of the tenon when it comes off the first pivot area in case of a shock to the wearer.

[0062] The curve of the intersection of a plane passing through axis A1 and perpendicular to face 11 of the bearing defining the wall of the second clearance area is preferably convex, where "convex" means that a straight line segment joining any two points of the curve lies within the material forming the bearing.

[0063] The maximum diameter d of the second gap area 14 (measured perpendicular to the axis A1) e is preferably the minimum diameter d of the first turning area 13 or of the hole 10 (measured perpendicular to the axis A1) t More than four times or more than seven times.

[0064] The maximum cross-sectional area of ​​the second gap region 14 (measured perpendicular to axis A1) is more preferably greater than 10 or 25 or 30 or 50 times the minimum cross-sectional area (measured perpendicular to axis A1) of the first swirl region 13 or hole 10.

[0065] The first volume defined by the first pivoting area 13 and the two planes P2, P3 perpendicular to the axis A1 and passing through the ends of the first pivoting area 13 relative to the axis A1 is advantageously smaller than 0.4 or 0.35 or 0.3 or 0.25 times the second volume defined by the second clearance area 14 and the two planes P1, P2 perpendicular to the axis A1 and passing through the ends of the second clearance area relative to the axis A1. The first volume defined by the first pivoting area 13 and the two planes P2, P3 perpendicular to the axis A1 and passing through the ends of the first pivoting area 13 relative to the axis A1 is greater than 0.1 or 0.15 or 0.2 times the second volume defined by the second clearance area 14 and the two planes P1, P2 perpendicular to the axis A1 and passing through the ends of the second clearance area relative to the axis A1.

[0066] More advantageously, the second volume constitutes at least 65%, or at least 70%, or at least 80% of a third volume bounded by the surface of the hole and two planes P1, P4 perpendicular to the axis A1 and passing through the ends of the hole relative to the axis A1.

[0067] The first turning zone 13 may advantageously have a different roughness than the second interstitial zone 14. More specifically, the first turning zone may have an oleophilic surface, while the second interstitial zone may have an oleophobic surface over its entirety or in part. These roughnesses or structures may be obtained by surface texturing or treatment, preferably surface texturing with a femtosecond laser. These roughnesses or textures may be obtained directly during the machining of the various zones or in a subsequent complementary final processing step.

[0068] In one embodiment, the diameter d t is 0.076 mm, and the diameter d e The minimum diameter d of the first turning area or hole 10 is 0.555 mm. tThe location including the axis A1 may or may not constitute the center of the turning area 13. t More specifically, the plane P5 passing through a location including the planes P2 and P3 may or may not be equidistant from the planes P2 and P3.

[0069] If any, the third interstitial region 15 may have an flared shape. The third interstitial region may form a flared or extension from the first pivot region to the second face 12. The third interstitial region 15 preferably has a frustoconical or substantially frustoconical shape.

[0070] There need not be any visually perceptible demarcation, for example an edge or a vertex, between the first pivot zone 13 and the third clearance zone 15. In fact, the bearing surfaces defining these zones may advantageously be connected to one another with a chamfered connection or may be connected to one another without forming an edge. Thus, the direction of a plane tangent to the surface of the hole evolves without discontinuities or abrupt changes of direction when the plane is moved within the hole onto the first pivot zone or onto the third clearance zone. In particular, the direction of a plane tangent to the surface of the hole evolves without discontinuities or abrupt changes of direction when the plane is moved within the hole from any point of the first pivot zone to any point of the third clearance zone. In other words, the curve of intersection of a plane passing through the axis A1 and perpendicular to the face 11 of the bearing 1 defining the walls of the first pivot zone and the third clearance zone does not feature any corner points at the intersection between the first pivot zone and the third clearance zone or does not feature any corner points in all of their extents. The minimum radius of curvature of the surface of the hole 10 at the intersection of the first turning area and the third clearance area, or the minimum radius of curvature of the chamfered connection, is preferably greater than 0.05 mm.

[0071] A portion of the chamfered connection forms part of the first pivot region and another portion of the chamfered connection forms part of the third gap region.

[0072] The boundary between the first pivot area and the third clearance area is, for example, such that the diameter of the hole (measured perpendicular to the axis A1) is greater than or equal to the minimum diameter d of the first pivot area or hole 10 (measured perpendicular to the axis A1).t Alternatively, the boundary between the first swirl zone and the third clearance zone is arbitrarily defined as, for example, the location where the cross-sectional area of ​​the hole (measured perpendicular to axis A1) is equal to 1.04 times the smallest cross-sectional area (measured perpendicular to axis A1) of the first swirl zone or hole 10. Said boundary is referenced 17 in FIG.

[0073] The tenon bearing 1 described above with reference to figures 1 and 2 has a particular shape, as mentioned above, which minimizes the risk of deterioration of the tenon during its insertion into the bearing. This type of bearing is advantageously made of synthetic ruby, as it has transparency and allows for an easy insertion of the tenon.

[0074] The present invention is based on a method for manufacturing tenon bearings, which is particularly suitable for manufacturing the above-mentioned bearings. Figure 8 shows a schematic flow chart of the steps of this type of manufacturing method according to an embodiment of the present invention. Of course, the same method remains suitable for the manufacture of any other tenon bearing and continues to provide high performances.

[0075] The method comprises a first step consisting of drilling E1 a hole 10a in the blank 1a of the bearing 1 along the axis A1 about which the watch part 2 is intended to rotate. This step is illustrated in Figure 3. This hole 10a allows the formation of the start 13a of the first pivoting section 13 mentioned above.

[0076] For this purpose, the method advantageously comprises a preparation substep, which comprises obtaining a bearing blank 1a. Said blank 1a advantageously takes the form of synthetic ruby ​​or polycrystalline corundum. Alternatively, the blank may take the form of other ceramics, such as zirconia, in particular yttria-zirconia, or monocrystalline alumina, or an alumina-zirconia combination. Furthermore, said blank 1a is advantageously arranged between a first plane 11a and a second plane 12a opposite and parallel to the first plane 11a. These two faces 11a, 12a of the blank 1a form the blanks of the faces 11, 12 of the future bearing 1. Both are located in planes P1, P2, respectively. The method then comprises a substep E11, which comprises drilling a hole 10a. Said hole 10a is advantageously a through hole. It is oriented perpendicular to said two faces 11a, 12a. It is centred on the axis A1. The holes advantageously have a cylindrical shape. The drilling may be achieved mechanically, by means of a broaching tool, or by means of a laser beam, in particular a femtosecond laser beam.

[0077] The first step is to determine the minimum diameter d of the first turning area 13 of any other future bearing 1 under manufacture. t Alternatively, the diameter d t may be obtained exclusively using the first sub-step described above.

[0078] The first step may further optionally include the outer diameter d ext This includes the lathe machining sub-step E13.

[0079] The method then comprises a second step consisting of laser engraving E2 of the blank 1a, in particular by means of a femtosecond laser, of the second clearance area 14 of the bearing 1, as shown in Fig. 4. Said engraving is carried out at the height of the hole 10a drilled in the preceding step. The second clearance area 14 to be formed is adjacent to the start 13a of the first pivot area 13. Furthermore, the second clearance area opens at the height of the first face 11a of the blank 1a of the bearing 1.

[0080] The laser used in the second step is preferably a femtosecond laser, which generates ultrashort pulses at a wavelength adapted to not affect the structure of the blank 1a material in such a way that it does not thermally affect the machining material. The laser beam 400 may be an infrared laser beam, in particular an infrared laser beam with a wavelength between 800 nm and 1100 nm, in particular a wavelength of 1030 nm ± 5 nm, or a green laser beam, in particular a green laser beam with a wavelength between 500 nm and 540 nm, in particular a wavelength of 515 nm ± 2.55 nm, or an ultraviolet laser beam, in particular an ultraviolet laser beam with a wavelength below 400 nm, in particular a wavelength of 343 nm ± 25 nm, or a blue laser beam, in particular a blue laser beam with a wavelength between 400 nm and 480 nm. Further, the laser beam may have an energy of 0.001 mJ to 2 mJ, or 0.004 mJ to 0.1 mJ, or 0.004 to 0.05 mJ. The laser beam may have a diameter of 5 μm to 100 μm, preferably 10 μm to 60 μm, or 15 μm to 30 μm. Between The diameter of the axial length of the axial groove may be 1.0 mm.

[0081] According to this embodiment, the step involving the laser engraving E2 of the second clearance area 14 of the bearing 1 comprises a number of successive sub-steps involving the engraving of the bearing 1 blank 1a in a number of distinct planes P. In other words, each sub-step may employ the engraving of a new plane distinct from the previously engraved plane, which may optionally undergo a complementary engraving, without thus excluding the engraving of several planes in the same sub-step. The above-mentioned distinct planes P are advantageously planes parallel to one another. The distance between two successive planes of the above-mentioned distinct planes P is preferably equal to or less than 2 μm, or even equal to or less than 1 μm. Both are advantageously substantially parallel to the first surface 11a of the blank 1a, overlap each other and extend in the first plane P1 between the first surface 11a of the blank and an intermediate plane P5 located within the thickness of the bearing 1 blank 1a. For this reason, the laser engraving step is also advantageously carried out at a starting point 13a, at the height of the future first turning area 13, between the intermediate plane P5 and the above-mentioned plane P2 forming the boundary between the first turning area 13 and the second gap area 14. Thus, a portion 14a is formed, which is located at the height of the boundary area between the first turning area 13 and the second gap area 14. The step naturally also forms the second gap area 14 itself, between the two planes P1, P2.

[0082] Each sub-step of the second step including laser engraving E2 advantageously employs an engraving inscribed in a circular contour centered on the axis A1 of the hole 10a, the diameter of which may decrease between the upper face 11a (or plane P1) and the intermediate plane P5, the engraving diameter at the intermediate plane P5 being substantially equal to the diameter of the hole 10a.

[0083] More specifically, the second step comprising laser engraving E2 may comprise n sub-steps E2i, where 1≦i≦n, of the passage of the laser beam 400 in n planes P, parallel or substantially parallel to the planes P1 and P5 and located between the planes P1 and P5. The laser beam passes through the n planes P, more specifically at the height of each of the planes P located between the planes P1 and P5, centered on the axis A1 and having a diameter d iIt passes through n surfaces, each circumscribed by a circle. These sub-steps may be specified in the following manner. - The first sub-step E21 may consist of passing the laser beam 400 at a substantial height of the plane P1. More specifically, the first sub-step E21 may consist of passing the laser beam 400 along a predetermined trajectory over a surface circumscribed by a circle having an axis A1 with a diameter d1 = d e of the axis A1. - After the first sub-step E21 and until reaching the plane P5, n - 2 sub-steps are performed in which the laser beam is moved along a predetermined trajectory within n - 2 surfaces, each arranged at a height of a plane P that is an increasingly large distance from the plane P1 based on a movement parallel or substantially parallel to the axis A1, where 1 < i ≤ n. In each plane P, the sub-step E2i may consist of passing the laser beam 400 along a predetermined trajectory over a surface circumscribed by a circle having an axis A1 with a diameter d i where d t ≤ d i ≤ d e is satisfied. - In the final sub-step E2n, the laser beam 400 is moved along a predetermined trajectory at the height of the plane P5. More specifically, the final sub-step E2n may consist of passing the laser beam 400 along a predetermined trajectory over a surface circumscribed by a circle having an axis A1 with a diameter d n = d t of the axis A1.

[0084] Note that the engraving in each plane has a small thickness, which is why the engraving is regarded as surface engraving. Nevertheless, this thickness is sufficient to form an engraving capacity by superimposing all the engravings on the various surfaces described above.

[0085] In the embodiment described above, each sub-step of the second step including laser engraving E2 advantageously performs an engraving inscribed in a circular contour centered on the axis A1 of the hole 10a and whose diameter decreases between the upper face 11a (or plane P1) and the intermediate plane P5, the engraving diameter on the plane P1 being equal to or smaller than the diameter d e and the engraving diameter on the intermediate surface P5 may be equal to the diameter d t may be substantially equal to

[0086] Alternatively, each sub-step of the second step comprising laser engraving E2 may advantageously carry out an engraving in a new plane P inscribed in a circular contour centred on the axis A1 of the hole 10a. Such a sub-step may simultaneously carry out a complementary engraving of an already engraved plane. Thus, in each sub-step, an already engraved plane may be engraved again on a surface of an enlarged radius inscribed in a circular contour centred on the axis A1. Thus, the engraving diameter of each already engraved plane P increases with each sub-step. By way of example, the engraving in plane P1 increases with each sub-step and finally reaches the value d in the first sub-step. t From the value d at the last substep e may change to.

[0087] As a further alternative, each sub-step of the second step including laser engraving E2 is advantageously centered on the axis A1 of the hole 10a, the diameter of which has a value d t and d e In this case, the laser can engrave multiple planes P in sub-steps as described above.

[0088] As mentioned above, the distance between the planes P is adapted to obtain a maximum continuous finished surface in the height of the walls of the second interstitial area 14 .

[0089] Finally, the step involving laser engraving E2 of the second clearance area 14 of the bearing 1 performs an engraving of a surface having some or all of the following characteristics: - the second clearance area 14 forms a continuous, endless extension or expansion from the first pivot area 13 of the bearing 1 (or from the start 13a of said first pivot area) to the first face 11a of the bearing 1; - the second interstitial area 14 has a substantially frustoconical shape, in the form of a truncated cone, of straight or curved surfaces, in particular with a radius of curvature going to infinity in the vicinity of the first face 11a; - the maximum diameter d of the second gap area 14 e is the minimum diameter d of the first turning area 13 t greater than four times or greater than seven times; - the maximum cross-sectional area of ​​the second clearance area 14 is greater than 10 times, 25 times, 30 times or 50 times the minimum cross-sectional area of ​​the first turning area 13; - the first volume limited by the first pivoting area 13 (between the two planes (P2, P3) perpendicular to the axis A1) is less than 0.4 or 0.35 or 0.3 or 0.25 times the second volume limited by the second clearance area 14 (between the two planes (P1, P2) perpendicular to the axis A1), and / or the first volume limited by the first pivoting area 13 (between the two planes (P2, P3) perpendicular to the axis A1) is greater than 0.1 or 0.15 or 0.2 times the second volume limited by the second clearance area 14 (between the two planes (P1, P2) perpendicular to the axis A1); the curve of the intersection of the second gap area 14 with a plane passing through the axis A1 and perpendicular to the face 11a or 11 is convex.

[0090] The method then comprises a third step, which comprises removing material by means of an abrasion E3 at the height of the start 13a of the first pivoting area 13 of the bearing 1 and at the height of a boundary area 14a between the start 13a of the first pivoting area 13 of the bearing 1 and the second clearance area 14 of the bearing 1, in order to form the first pivoting area 13 and the second clearance area 14 of the bearing 1 in an adjacent manner, connected to each other by a chamfered connection. The third step of removing material by means of an abrasion E3 may be an olive cutting step, as shown in Figures 5 and 6.

[0091] More specifically, the third step may consist in passing a diamond thread 500 through the hole 10a and moving the bearing blank 1a relative to it, thereby giving the starting point 13a the final shape of the first turning section 13 and modifying its cylindrical nature. This shape is sometimes referred to as an "olive" shape. At the end of the second step, the first turning section 13 is free of any ends. The minimum diameter d t is measured considering a circle in the intermediate plane P5 having a diameter tangent to the connecting wall of the nearest first turning area 13.

[0092] In a complementary manner, the diamond thread 500 also acts at least on the starting point 13a or on the boundary portion 14a of the second gap region 14 adjacent to the first turning region 13. Thus, the first and second regions 13, 14 are connected to each other without an end and / or with a chamfered connection. These first and second regions 13, 14 thus form a continuous wall or a continuous surface, due to the synergistic effect of two techniques, the first being laser engraving and the second being material removal by abrasion.

[0093] The diamond thread 500 also acts on the junction of the bore 10a and the second face 12a of the blank 1a. The transition area between this second face 12a and the first pivot area 13 forms the above-mentioned third clearance area 15. The first and third areas 13, 15 are thus connected to each other without any edges and / or by a chamfered connection thanks to said third step. The third clearance area 15 is located in the blank 1a in the widening of the bore 10a and opens out at the level of the second face 12a of the bearing 1 blank 1a.

[0094] Subsequently, the method optionally comprises a fourth finishing step E4, by buffing or polishing, in order to obtain the finished bearing 1. Such a step may consist of buffing the bearing 1 blank 1a with diamond paste. This step may comprise various sub-steps aimed at minimizing the roughness of the walls and faces 11a, 12a of the bearing blank 1a, in particular of the second clearance area 14. Sub-steps may in particular be provided to give the second face 12 of the bearing a domed appearance. Figure 7 illustrates the tenon bearing 1 finally obtained after carrying out this fourth finishing step E4, in particular the above-mentioned sub-steps. It is noted here that the bearing 1 comprises a hole 10, bounded by the surfaces of the various areas 13, 14, 15 formed by the method of the invention from the initial hole 10a of the blank, thus forming itself the blank for the future hole 10.

[0095] In an alternative embodiment of the method, a fourth finishing step E4 may be inserted between the second step E2 and the third step E3, where what is most important is that the third step E3 is accomplished downstream of the second step E2.

[0096] An optional step E5 of texturing all or part of the interstitial areas 14 and / or all or part of the interstitial areas 15 may also be provided. This step is preferably performed using a femtosecond laser. This step may be accomplished upstream or downstream of the finishing step E4. Of course, the method described above is particularly suitable for forming tenons, as shown in Figures 1 and 2, but is equally suitable for the manufacture of any other type of watch bearing.

Claims

1. A method for manufacturing a tenon bearing (1) for pivoting a watch part (2), comprising the steps of: Drilling (E1) of a hole (10a) in the blank (1a) of the bearing (1) along the axis (A1) about which the watch part (2) is intended to rotate, said hole (10a) forming the start (13a) of a first pivoting section (13) of said bearing (1), then Laser engraving (E2) of a second clearance area (14) of the bearing (1) adjacent to the start (13a) of the first pivoting area (13) into the blank (1a), the second clearance area (14) of the bearing (1) opening onto the first face (11a) of the blank (1a) of the bearing (1), thereafter removal of material by abrasion (E3) at the start (13a) of the first swivel region (13) of the bearing (1) and at the boundary region (14a) between the start (13a) of the first swivel region (13) of the bearing (1) and the second clearance region (14) of the bearing (1) for the formation of a first swivel region (13) and a second clearance region (14) of the bearing (1) which are adjacent and connected to each other by a chamfered connection; A method comprising the steps of:

2. said step involving the drilling (E1) of the holes (10a) comprises a sub-step involving obtaining a blank (1a) arranged between a first plane (11a) and an opposite second plane (12a), and then drilling a through hole (10a) in a direction perpendicular to said first plane (11a); A method for manufacturing a tenon bearing (1) according to claim 1.

3. the step involving laser engraving (E2) of the second clearance area (14) of the bearing (1) comprises a plurality of successive sub-steps, each sub-step involving engraving the bearing (1) blank (1 a) in at least one plane distinct from the laser engraving of the preceding sub-step, A method for manufacturing a tenon bearing (1) according to claim 1 or 2.

4. the separate planes of the successive sub-steps are mutually parallel planes, substantially parallel to the first face (11a) of the blank (1a), and overlap each other, extending between the first face (11a) of the blank and a mid-plane (P5) located within the thickness of the bearing (1) blank (1a); A method for manufacturing a tenon bearing (1) according to claim 3.

5. Each sub-step of the step involving laser engraving (E2) performs an engraving circumscribing a circular contour centered on the axis (A1) of the hole (10a) in a new separate plane, the diameter of which decreases between the first face (11a) and the intermediate plane (P5), such that the step involving laser engraving (E2) generates a second gap area (14) formed by engraving superimposed circular plates of separate planes, the diameter of the engraving in the intermediate plane (P5) being substantially equal to the diameter of the hole (10a), A method for manufacturing a tenon bearing (1) according to claim 4.

6. The distance between two consecutive planes of the separate planes is 2 μm or less, or 1 μm or less; A method for manufacturing a tenon bearing (1) according to any one of claims 3 to 5.

7. The step comprising laser engraving (E2) of the second clearance area (14) of the bearing (1) comprises: the second clearance area (14) forms a continuous, endless extension or expansion from the first pivot area (13) of the bearing (1) to the first surface (11) of the bearing (1); The second interstitial area (14) has a substantially frustoconical shape, in the form of a truncated cone, of straight or curved surfaces. the maximum diameter (de) of the second clearance region (14) is greater than four times, or greater than seven times, the minimum diameter (dt) of the first turning region (13); The maximum cross-sectional area of ​​the second clearance region (14) is greater than 10 times, 25 times, 30 times, or 50 times the minimum cross-sectional area of ​​the first turning region (13); a first volume limited by the first swirl zone (13) and the two planes (P2, P3) perpendicular to the axis (A1) is less than 0.4 times, 0.35 times, 0.3 times, or 0.25 times the second volume limited by the second clearance zone (14) and the two planes (P1, P2) perpendicular to the axis (A1); and / or a first volume limited by the first swirl zone (13) and the two planes (P2, P3) perpendicular to the axis (A1) is greater than 0.1 times, 0.15 times, or 0.2 times the second volume limited by the second clearance zone (14) and the two planes (P1, P2) perpendicular to the axis (A1); the curve of the intersection of the second gap area (14) with a plane passing through the axis (A1) and perpendicular to the first surface (11) is convex; 3. Carry out engraving of a surface having some or all of the characteristics of A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 6.

8. The step involving removal of material by abrasion (E3) uses a diamond thread; A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 7.

9. said step comprising drilling (E1) of a hole (10a) in the bearing (1) blank (1a) using a broaching tool or a laser; A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 8.

10. said step comprising (E1) drilling (10a) a hole (10a) in a bearing (1) blank (1a) comprises an enlarging sub-step (E12) comprising providing said hole (10a) with a diameter substantially equal to the minimum diameter (dt) of said first turning area (13) of said bearing (1); A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 9.

11. The step of turning (E13) the outer diameter (dext) of the bearing (1), A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 10.

12. Including a buffing or polishing step (E4), A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 11.

13. rounding said second surface (12a) of said blank (1a) opposite said first surface (11a) to form a dome-shaped second surface (12) of said bearing (1) and optionally to form a third clearance area (15) in the widening of said hole (10a) of said blank (1a) at the level of said second surface (12), A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 12.

14. a step (E5) of texturing part or all of said second interstitial zone (14) and / or part or all of said third interstitial zone (15) so that said first interstitial zone (13) has a roughness different from the roughness of said second interstitial zone (14) and / or so that said first interstitial zone (13) has an oleophilic surface and said second interstitial zone (14) has, in whole or in part, an oleophobic surface, A method for manufacturing a tenon bearing (1) according to claim 13.

15. The blank (1a) is made of ceramic, such as synthetic ruby ​​or polycrystalline corundum, or zirconia, or monocrystalline alumina, or alumina-zirconia bond. A method for manufacturing a tenon bearing (1) according to any one of claims 1 to 14.

Images