Method and system for cleaning watch stones

Abstract

A method for manufacturing a watch part (1), in particular a tenon (1), including a hole (5), comprising the steps of: machining the hole (5) by abrasion using abrasive particles (21), in particular diamond particles, which are free with respect to a machining support (20) and roll between the surface (6) of the hole to be machined and the machining support (20) housed in the hole, and / or using abrasive particles that can be detached from the machining support, then cleaning the watch part (1) and the machining support (20) while the machining support is housed in the hole, and then removing the machining support from the hole.

Description

[Technical Field]

[0001] The present invention relates to a tenon stone for a clock movement. The invention also relates to a method for manufacturing the tenon stone and a machine for grinding the tenon stone. The invention also relates to a method for determining the surface roughness of the mortise hole of the tenon stone. The invention also relates to a clock part comprising the tenon stone. The invention also relates to a clock movement comprising the tenon stone or the clock part. Finally, the invention relates to a clock comprising the clock movement or the tenon stone or the clock part.

[0002] The present invention also generally relates to a method for manufacturing a part that includes a hole. - the watch parts in question, - watch movements containing such watch parts; and - a watch, including such a watch movement or such a watch part; Regarding. [Background technology]

[0003] The watch jewel is a key element for the good functioning of a watch movement: almost all rotary motion is carried out by an arbour that pivots in a bearing made of a drilled ruby ​​element, also called a functional stone or tenon.

[0004] To manufacture tenons, it is known practice to form boules of material, particularly boules of synthetic ruby, and more particularly boules of single crystal synthetic ruby, into plates of a predetermined thickness by sawing or wire cutting or laser cutting. These plates are then cut to form stone blanks (preparations), which are then given a cylindrical outline by, for example, a lathe operation.

[0005] The stone is then drilled, for example by laser or spindle, to obtain the rough mortise. The stone is then subjected to an enlarging step, which makes it possible to achieve the final diameter and desired surface finish of the mortise. A subsequent turning step makes it possible to give the stone its nominal outer diameter. An optional grooving operation makes it possible to form recesses on one or both sides of the stone to serve as lubrication reservoirs. Finally, grinding brings the stone's thickness to the final dimensions and the desired surface finish. A possible final finish makes it possible to obtain the desired outer surface finish. This grinding does not change the surface finish of the mortise.

[0006] The enlargement step is important because it determines not only the dimensions of the mortise but also the surface finish. For this purpose, the stones are attached to a wire and secured together, allowing them to both be rotated around the axis of the mortise and processed as a batch. The wire is typically conical, with a diameter gradually increasing to the desired final diameter. By adding abrasive and moving the wire back and forth, the hole is gradually enlarged until it reaches its final dimensions. The rotational speed of the stone is significantly slower than the translational speed of the wire, and machining is primarily accomplished by the back and forth movement of the wire. Therefore, any residual machining marks are necessarily oriented along the axis of the mortise or tenon, although the inclination of the marks relative to the axis of the mortise or tenon will be several degrees, depending on the rotational speed and movement of the wire relative to the stone. The equipment and principles used in the enlargement method do not allow for different orientations of the residual machining marks to be obtained.

[0007] For some tenon stones, it is desirable to obtain olive-cut holes, i.e., non-cylindrical holes with a convex, rounded profile that reduces the diameter of the hole toward its center. Such olive-cut holes reduce the surface area over which the mortise can rub against the tenon, making lubrication easier. To obtain olive-cut holes, the stone is remounted on the wire and then subjected to the specific olive-cut method described below. Stones with straight or cylindrical holes are not olive-cut and are not subjected to any other method except for the enlargement described above.

[0008] Non-Patent Document 1 discloses the main steps of the method for producing various stones and various types of stones. The olive cutting method is illustrated in Figure 4 of the document. The operation is carried out mechanically by tilting the stone on a spirally grooved roller using a wire of precise diameter and coated with a diamond suspension. The stone is driven along the roller through the groove, and the wire wears the end of the tenon. By carefully selecting the parameters, it is possible to reverse the direction of tilting the stone in the middle of the roller, thereby obtaining an olive cut that is as uniform and symmetrical as possible.

[0009] US Patent Nos. 5,999,949 and 5,999,952 disclose machines for producing stones using wires coated with a mixture of oil and diamond powder, by means of an axial back and forth movement, either for reaming / enlarging or for olive cutting by tilting the stone.

[0010] Patent document 3 highlights the effect of the olive cut of the stone, which makes it possible to reduce friction.

[0011] Patent document 4 discloses a method for manufacturing stones that allows obtaining a very low surface roughness, followed by the treatment of the friction area to obtain a topography / roughness suitable for retaining lubricants by intentionally manufacturing small holes, grooves, roughness or undulations. These asperities have the order of magnitude of the size of some of the particles of the lubricant used, i.e., according to the applicant, a fraction of a micrometer. However, the document does not cite any values ​​or quantitative factors, nor does it mention a specific method for obtaining the surface finish in question.

[0012] US Patent No. 5,649,999 discloses a sintered stone in which holes are formed by a laser and then finished by lapping, brushing and / or polishing to correct localized roughness, but does not disclose further details.

[0013] Patent Documents 6 and 7 also relate to various aspects of methods for producing polycrystalline stones by pressing. These stones have the particular feature of containing enlarged holes, the minimum diameter of which can be less than 0.11 mm. The purpose of the method in this case is to provide an alternative to methods using lasers, which, according to the applicant, do not directly produce a high-quality surface finish. While producing stones by pressing allows for a good surface finish, drilling stones using a femtosecond laser only produces an insufficient surface finish. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Swiss Patent Application Publication No. 121766 [Patent Document 2] Swiss Patent Application Publication No. 336311 [Patent Document 3] Swiss Patent Application Publication No. 706268 [Patent Document 4] Swiss Patent Application Publication No. 393194 [Patent Document 5] European Patent Application Publication No. 2778801 [Patent Document 6] European Patent Application Publication No. 3835881 [Patent Document 7] European Patent Application Publication No. 3835882 [Patent Document 8] International Publication No. 2021 / 032552 [Non-patent literature]

[0015] [Non-Patent Document 1] "The Watch Stone," Pierhor SA, Societe Suisse de Chronometrie (Swiss Chronometry Society) Bulletin No. 69, June 2012 Summary of the Invention [Problem to be solved by the invention]

[0016] The object of the present invention is to provide a tenon that functions well and makes it possible to improve upon known tenons of the prior art. In particular, the present invention proposes a tenon with improved turning characteristics, in particular with improved roughness characteristics, and a method relating to said tenon. [Means for solving the problem]

[0017] According to a first aspect, the invention is defined by the following propositions:

[0018] 1. A tenon (1) for a timepiece movement (100), said tenon (1) comprising a mortise (5) having a first axis (A1) and capable of pivoting on or around a timepiece part (98), such as a timepiece stem, said mortise comprising a surface (6) bearing primary abrasive-machining streaks (61), in particular primary abrasive streaks, oriented radially and substantially perpendicular to said first axis (A1); Mortise stone (1).

[0019] 2. The main machining marks (61) have a helix angle of less than 1°, or less than 0.5°; Mortise stone (1) as described in Proposal 1.

[0020] 3. The main machining marks (61) are parallel or substantially parallel to a plane perpendicular to the first axis (A1) and / or form an angle with the plane perpendicular to the first axis (A1) of less than 1° or less than 0.5°; Mortise stone (1) as described in proposal 1 or 2.

[0021] 4. The primary machining marks (61) have an orientation dispersion of plus or minus θ about the average orientation, where θ>0.2°, and in particular θ is about 0.5°; A tenon stone (1) according to any one of proposals 1 to 3.

[0022] 5. The roughness Ra of the surface, in particular the roughness Ra of the surface (6) measured parallel to the first axis (A1) or perpendicular to the main scratches (61), is less than 20 nm, or less than 10 nm, or less than 5 nm; A tenon stone (1) according to any one of proposals 1 to 4.

[0023] 6. The diameter of the mortise hole (5) is less than 2.5 mm, or less than 2 mm, or less than 1.6 mm, or less than 0.6 mm, or less than 0.3 mm; A tenon stone (1) according to any one of proposals 1 to 5.

[0024] 7. The contour of the surface (6) of the mortise (5) through a plane passing through the first axis (A1) is linear or cylindrical; A tenon stone (1) according to any one of proposals 1 to 6.

[0025] 8. The profile of the surface (6) of the mortise (5) through a plane passing through the first axis (A1) is convex when viewed from the first axis (A1), with a deviation of less than 1 μm, or less than 0.5 μm, or less than 0.25 μm; A tenon stone (1) according to any one of proposals 1 to 6.

[0026] 9. The tenon (1) is made of technical ceramic, in particular ruby. A tenon stone (1) according to any one of proposals 1 to 8.

[0027] 10. The mortise stone (1) comprises a rolling surface (7), in particular a rolling surface (7) of a first axis (A1), intended to roll on a watch part; A tenon stone (1) according to any one of proposals 1 to 9.

[0028] 11. The shape and / or positioning of the main scratches is not controlled; A tenon stone (1) according to any one of proposals 1 to 10.

[0029] 12. The surface (6) - strictly greater than 0, in particular greater than 1%, and - less than 10%, especially less than 3%, Shows isotropy, A tenon stone (1) according to any one of proposals 1 to 11.

[0030] 13. A watch part (98), in particular a wheel (98), in particular a second wheel, comprising at least one tenon stone according to any one of suggestions 1 to 12, in particular at least two tenon stones according to any one of suggestions 1 to 12.

[0031] 14. A clock movement (100) comprising at least one tenon stone according to any one of suggestions 1 to 12, in particular at least two tenon stones according to any one of suggestions 1 to 12, and / or a clock part (100) according to suggestion 13.

[0032] 15. The at least one jewel pivots a watch part, and the watch part - balance wheel, or - Ankle set, or - Escape wheel, That is, A clock movement (100) as described in Proposal 14.

[0033] 16. The at least one stone is: - Sun's back car, or - Third wheel, or - Seconds wheel, Such as the final gear, which rotates the clock parts, A clock movement (100) as described in Proposal 14.

[0034] 17. The at least one jewel is a wheel in the automatic winding drive train, which rotates the watch component. A clock movement (100) as described in Proposal 14.

[0035] 18. - At least one tenon stone (1) according to any one of proposals 1 to 12, and / or - watch parts (98) as described in Proposal 13, and / or - a clock movement (100) according to any one of proposals 14 to 17, Clocks (200), including watches, especially wristwatches.

[0036] According to a second aspect, the invention is defined by the following propositions:

[0037] 19. A method for manufacturing a mortise (1) for a timepiece movement (100), said mortise (1) comprising a mortise (5) having a first axis (A1), in particular a linear or cylindrical mortise having a first axis (A1), capable of pivoting around a timepiece part (98), such as a watch stem, said method comprising: (i) using free abrasive particles (21), in particular diamond particles, which roll between the surface (6) of the mortise (5) to be ground and a grinding support (20), such as a wire (20); and / or (ii) the tenon stone (1) is driven in a rotational movement about the first axis (A1) relative to a grinding support (20) which is pulled back towards the surface (6) of the tenon stone (5) to be ground; Including the first step of polishing, Manufacturing method.

[0038] 20. During the first step of grinding, the tenon stone (1) is held in position against the grinding support (20) by contact with its peripheral surface (7); The manufacturing method described in Prop. 19.

[0039] 21. The first axis (A1) is parallel or substantially parallel to the surface of the abrasive support (20), and / or the first axis (A1) is parallel or substantially parallel to the second axis (A3) of the abrasive support (20), the abrasive support consisting in particular of a wire (20); The manufacturing method described in Proposal 19 or 20.

[0040] 22. During the first step of grinding, the tenon (1) is driven relative to the grinding support (20) by contact with its peripheral surface (7); The manufacturing method described in any one of proposals 19 to 21.

[0041] 23. During the first step of grinding, the tenon (1) is driven in a linear spiral or rotational movement about the first axis (A1) relative to the grinding support (20); The manufacturing method according to any one of proposals 19 to 22.

[0042] 24. The angle between the first axis (A1) and the second axis (A3) of the grinding support is less than 0.5°; The manufacturing method according to any one of proposals 19 to 23.

[0043] 25. The free abrasive particles (21) are contained in a suspension, in particular an aqueous or oil-based suspension, which coats the abrasive support; A manufacturing method according to any one of proposals 19 to 24.

[0044] 26. During the first step of grinding, a gap between the grinding support (20) and the tenon (5) is formed, between 5 μm and 20 μm, typically 10 μm. A manufacturing method according to any one of proposals 19 to 25.

[0045] 27. The method comprises, after the first step of grinding, a second step of machining recesses (3) in one or two faces (2, 4) of the tenon (1), said faces (2, 4) extending perpendicular or substantially perpendicular to the first axis (A1); A manufacturing method according to any one of proposals 19 to 26.

[0046] 28. The method comprises, after the first step of grinding, a third step of grinding at least one face (2, 4) of the tenon (1), preferably two faces, said faces (2, 4) extending perpendicular or substantially perpendicular to the first axis (A1); A manufacturing method according to any one of proposals 19 to 27.

[0047] 29. The velocity of the tenon (1) relative to the grinding support (20) in the radial direction perpendicular to the first axis (A1) at the point of contact with the grinding support (20) is in the range between 1 m / s and 10 m / s, or between 1 m / s and 20 m / s; A manufacturing method according to any one of proposals 19 to 28.

[0048] 30. A machine (30) for grinding a mortise (5) of a tenon (1) of a watch movement (100), the tenon (1) having a mortise oriented along a first axis (A1), the machine comprising a drum (31) driven in rotation about a second axis (A2) and having a slot (32) forming a spiral that drives the tenon around the drum (31) and holds the position of the tenon so that, at the point of contact between the tenon and the slot, the first axis (A1) is perpendicular to the plane of contact of the spiral. polishing machine.

[0049] 31. A grinding support (20) having a second axis (A3), the second axis (A3) of the abrasive support and / or the first axis (A1) of the mortise is perpendicular to the tangent of the spiral of the slot, and / or the second axis (A3) of the abrasive support and / or the first axis (A1) of the mortise is perpendicular to the contact plane of the spiral of the slot at the point of contact between the mortise stone and the slot (32); Abrasive machines as described in Prop. 30.

[0050] 32. The spiral around the drum (31) has a helix angle of less than 0.1° or less than 0.05°. Abrasive machines as described in proposals 30 or 31.

[0051] 33. The machine comprises a wire-shaped grinding support (20) intended to hold the mortise stone at the bottom of the slot (32) and to grind the mortise hole (5) by abrasion; A grinding machine according to any one of proposals 30 to 32.

[0052] 34. The machine includes an element (35) for setting the orientation of the grinding support (20) relative to the second axis (A2); A grinding machine according to any one of proposals 30 to 33.

[0053] 35. The machine includes a clamp (33) for dispensing the tenon stones (1), the clamp being arranged to feed the tenon stones to the drum (31) by providing them one at a time to the drum; A grinding machine according to any one of proposals 30 to 34.

[0054] 36. The diameter of the drum (31) is greater than 10 cm, and / or the contour of the slot is U-shaped or rectangular, in particular without a chamfer at the bottom of the slot, in order to facilitate the proper holding of the tenon stone in its vertical position relative to the drum (31). A grinding machine according to any one of proposals 30 to 35.

[0055] 37. A supply element (38) for depositing a suspension containing free abrasive particles (21) onto the abrasive support (20); A grinding machine according to any one of proposals 30 to 36.

[0056] According to a third aspect, the invention is defined by the following propositions:

[0057] 38. A method for manufacturing a watch part (1), in particular a mortise stone (1), including a hole (5), comprising: a step of machining the hole (5) by abrasion using abrasive particles (21), in particular diamond particles, which are free with respect to a machining support (20) and roll between the surface (6) of the hole to be machined and the machining support (20) housed in the hole, and / or using abrasive particles which are detachable from the machining support, then a step of cleaning the watch part (1) and the machining support (20) while the machining support is housed in the hole, then removing the machined support from the hole; Including, Manufacturing method.

[0058] 39. The cleaning step involves the use of a cleaning solution, in particular an aqueous or alcoholic or oily solution; Manufacturing methods described in Prop. 38.

[0059] 40. The cleaning step comprises immersing the watch part (1) and the machined support (20) in the cleaning solution; Manufacturing methods described in Prop. 39.

[0060] 41. The immersion step includes applying ultrasound waves to the cleaning solution. The manufacturing method described in Proposition 40.

[0061] 42. The cleaning step comprises spraying a cleaning solution onto the watch part (1) and the machined support (20); A manufacturing method according to any one of proposals 38 to 41.

[0062] 43. The cleaning step includes spraying with gas or steam; A manufacturing method according to any one of proposals 38 to 42.

[0063] 44. The cleaning step is carried out on a machining machine, in particular on a grinding machine, on which the step of machining the hole by abrasion was carried out. A manufacturing method according to any one of proposals 38 to 43.

[0064] 45. The washing step comprises: The watch component (1), The machined support (20) and is removed from a machining machine on which the step of machining the hole was performed by wear, A manufacturing method according to any one of proposals 38 to 43.

[0065] 46. ​​The cleaning step is carried out in a housing (80), the assembly consisting of the watch part (1) and the machined support (20) passing completely through the housing; A manufacturing method according to any one of proposals 38 to 45.

[0066] 47. The method according to any one of proposals 38 to 46, comprising hardware means (80, 81, 82, 83) for carrying out said step of cleaning the watch part (1) while the machined support is housed in the hole of the watch part (1), in particular: a housing (80), for example formed by two parts (81, 82) movable relative to one another as a whole, and / or having a passage for said machined support; Nozzles 83 and / or channels for spraying the cleaning solution; Including, Cleaning systems (84).

[0067] 48. A cleaning system (84) according to proposal 47, comprising hardware means (20, 31, 34, 35, 36, 37, 38, 39, 40, 84) for carrying out the method according to any one of proposals 38 to 46; Machining systems (30).

[0068] 49. Obtained by carrying out the method described in any one of proposals 38 to 46, Clock parts (1), especially mortise stones (1).

[0069] 50. Including the watch parts (1) described in Proposal 49, Clock movement (100).

[0070] 51. A watch component according to proposal 49 and / or a watch movement (100) according to proposal 50, Clock (200).

[0071] According to a fourth aspect, the invention is defined by the following propositions:

[0072] 52. A method for determining the roughness of the surface (6) of a mortise hole (5) of a mortise stone (1) of a watch movement (100), comprising: a first step of preparing the tenon (1), comprising removing a first part of the tenon (1), including (i) a portion of the surface (6) of the tenon (5), (ii) a portion of the outer surface (7) of the tenon (1), and (iii) a portion of the volume between the surface (6) and the outer surface (7) of the mortise hole, to obtain a second part of the tenon (1), thereafter a second step of measuring the surface (6) of the mortise hole (5) located in the second part of the mortise stone (1); Including, Specific method.

[0073] 53. The removal of the first part of the tenon is carried out through a plane passing through the axis (A1) of the mortise (5) or through a plane parallel to the axis (A1) of the mortise (5), and / or the first preparation step does not alter the surface (6) of the mortise (5) located in the second part of the tenon (1), but allows access to said surface; Identification methods described in Prop. 52.

[0074] 54. The removal is carried out by abrasion. Identification methods described in Propositions 52 or 53.

[0075] 55. Before the removal, a sub-step of assembling a plurality of tenons (1) is carried out; Identification methods described in Prop. 54.

[0076] 56. The substep of assembling one or more tenons (1) to the support is carried out before said removal. The identification method described in any one of Proposals 52 to 55.

[0077] 57. The substep of assembly includes mounting a tenon onto a wire; Identification methods described in Propositions 55 or 56.

[0078] 58. A substep of coating the tenon (1) or tenons (1) is carried out before the removal; The identification method described in any one of Proposals 52 to 57.

[0079] 59. The removal is carried out by fragmentation. Identification methods described in Propositions 52 or 53.

[0080] 60. The substep of creating a notch in the tenon (1) on one face (2, 4) of the tenon (1) is carried out before the fragmentation; Identification methods described in Prop. 59.

[0081] 61. The fragmentation is carried out by impacting one part of the tenon (1), the other part of the tenon being held by a support, the parts being separated by the notches; Identification methods described in Proposition 60.

[0082] 62. The removal is carried out by sawing or wire cutting; Identification methods described in Propositions 52 or 53.

[0083] 63. The second step of the measurement is carried out using laser scanning confocal microscopy. The method set forth in any one of proposals 52 through 62.

[0084] 64. The second step of the measurement comprises determining a direction perpendicular to the main machining marks (61) on the surface (6) of the mortise (5) of the mortise block (1); The method set forth in any one of proposals 52 through 63.

[0085] 65. The second step of the measurement is a linear measurement along the direction perpendicular to the main machining marks (61) on the surface (6) of the mortise (5) of the mortise stone (1). Methods as described in Proposition 64.

[0086] All features of the various aspects may be combined with each other except where logically or technically incompatible.

[0087] The accompanying drawings show, by way of example, embodiments of the tenon stone, grinding machine and associated method according to the invention. [Brief explanation of the drawings]

[0088] [Figure 1] FIG. 1 is a perspective view of a longitudinal section of one embodiment of a tenon stone according to the present invention. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of a number of tenons according to the present invention during polishing. [Figure 3] FIG. 3 is a schematic side view of one embodiment of a polishing machine according to the present invention. [Figure 4] FIG. 4 is a schematic top view of an embodiment of a polishing machine according to the present invention. [Figure 5] FIG. 5 is a schematic diagram illustrating a first embodiment of a timepiece according to the present invention. [Figure 6] FIG. 6 is a schematic diagram illustrating a second embodiment of a timepiece according to the present invention. [Figure 7]FIG. 7 is a schematic side view of one embodiment of a cleaning system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0089] Studies conducted by the applicant have demonstrated that the surface finish of the tenon area is extremely important to ensure the reliability of a watch movement, and in particular to ensure reliable rotation of the stem within the tenon. The applicant has observed that it is still possible to improve the wear resistance of the tenon by, among other things, removing or delaying the appearance of sticky black deposits that can cause performance degradation.

[0090] The developments made by the Applicant have made it possible to obtain a good surface finish in stone mortises, especially for stones with straight or cylindrical holes, i.e., holes without conical, frustoconical or olive-cut surfaces. These developments relate to a method for measuring roughness, a method for preparing stones for roughness measurement, a machine (or device) and method for obtaining an optimized surface finish by polishing, a method for cleaning stones after polishing, and stones with an optimized surface finish. In particular, the solution provided by the present invention makes it possible to obtain a roughness Ra of mortises of less than 10 nm, with the preferred orientation of the residual polishing marks in a radial direction perpendicular to the axis of the mortise. The marks are machining marks, especially polishing marks, whose shape and position on the surface of the mortise are largely uncontrolled and highly random. According to the present invention, the following was implemented: The depth of the scratches is roughly controlled by choosing an abrasive capable of producing nanometer depths, for example resulting in a roughness Ra of less than 20 nm, and - the orientation of the scratches is roughly controlled by a dispersion of orientations of plus or minus θ around the average orientation, where θ>0.2°, in particular where θ is about 0.5°; That is the thing.

[0091] As mentioned above, watch jewels are a key element in the reliability of a watch movement. The challenge is to obtain a suitable surface finish with optimal repeatability across all jewels within a single production batch and from one batch to the next. This is all the more necessary since inspecting the surface finish of mortise holes is extremely difficult and destructive.

[0092] Many pivoting movements of a watch movement are ensured and realized by jewels with a straight or cylindrical bore. This is the case, for example, with the pivoting movements of the minute wheel, third wheel, seconds wheel or calendar wheel. Generally, pivoting movements carried out by stems provided with small diameter pivots (spring-balance oscillator, pallet, anchor wheel) are provided by olive-cut jewels (i.e., jewels whose mortise holes have an olive cut), while stems with a larger diameter (for example, greater than 0.15 mm) are pivoted in straight jewels (i.e., jewels with a straight bore).

[0093] The applicant also emphasizes that a "cottoning" operation, carried out by moving a cotton thread carrying a suspension of diamond particles back and forth, makes it possible to obtain a better surface finish. However, this process is very difficult to implement for diameters smaller than 0.3 mm and is not applicable to the serial production of certain critical pivot bearings of final gears. For diameters smaller than 0.6 mm, this process can only be applied manually, and it has been proven that such manual polishing does not have the robustness of an industrial process and does not completely eliminate the wear phenomenon.

[0094] Furthermore, roughness measurements show that stones obtained by the standard magnification process have a high roughness, with the orientation of the residual grinding marks being axial (i.e. parallel to the axis of the tenon: this is reasonable considering the back and forth movement imparted to the stone relative to the wire during the process). The manual process described above allows for an improvement in roughness, but does not allow for the axial orientation of the marks to be changed. In order to eliminate the phenomenon of abrasion, the inventors emphasize that not only must the lowest possible roughness be obtained, but also that the orientation of the residual grinding marks must be in a perpendicular radial direction (relative to the axis of the tenon), in order to minimize the influence of the wear of the tenon on the tines that it is intended to undergo.

[0095] One embodiment of a tenon 1 of a timepiece movement 100 is shown in Figure 1. The tenon 1 has a cylindrical overall shape with an axis A1 and includes a mortise hole 5 along the axis A1. The mortise hole 5 includes a surface 6, in particular a cylindrical or substantially cylindrical surface 6, intended to pivot a timepiece part, such as a watch stem, or capable of pivoting around the timepiece part. Furthermore, the tenon 1 includes: an upper surface 2 and a lower surface 4, preferably both extending perpendicular to the axis A1; - a cylindrical outer surface 7 of the axis A1; Limited by.

[0096] The tenon may also have a recess 3 formed on the upper surface 2 and / or a recess formed on the lower surface 4. Thus, the tenon can have no recesses, a recess on one of the surfaces, a recess on each of the surfaces, or one curved surface or two curved surfaces.

[0097] Advantageously, the diameter of the mortise 5 is less than 2.5 mm, or less than 2 mm, or less than 1.6 mm, or less than 0.6 mm, or less than 0.3 mm.

[0098] The surface 6 has a main grinding streak 61 .

[0099] The tenon 1 is preferably made of technical ceramics, in particular corundum, spinel or zirconia, or of SiC or silica, or possibly of other natural or synthetic stones such as diamond. The tenon 1 may also be made of polycrystalline or monocrystalline corundum, for example ruby, in particular Cr-doped alumina, for example synthetic Cr-doped alumina, or even monocrystalline Cr-doped alumina. The tenon 1 may also be made of a combination of alumina and zirconia.

[0100] According to the invention, the method for manufacturing the tenon 1 of the watch movement 100 makes it possible to obtain a surface finish in the mortise 5 of the stone, in particular on the surface 6, with the lowest possible roughness and an orientation of the roughness, i.e. the orientation of the main scratches, in the direction of the relative movement between the stone and the watch part, in particular the arbour, that the tenon is intended to undergo. Said orientation is therefore radial, perpendicular to the axis A1. It is emphasized that said orientation makes it possible in particular to minimise the effects of abrasion and therefore wear at the contact points between the tenon and the watch part, in particular the arbour.

[0101] In one embodiment of the method for manufacturing a tenon, the procedure is preferably as described above, i.e. the following steps are carried out: - forming the material into plates, - cutting the plate into blanks, - Turning, - Drilling a rough turning hole, - Expanding in some cases, - Possibly one or more groove machining and grinding operations.

[0102] However, in addition to or as an alternative to the widening step, a specific polishing step of the tenon, described in more detail below, is carried out, which makes it possible to achieve the surface finish objectives mentioned above.

[0103] The polishing is a three-body polishing operation, as illustrated in FIG. 2. The polishing is carried out with a free abrasive 21 (in particular diamond grains of a given diameter in an aqueous or oil-based suspension) that rolls between the tenon and a suitably shaped polishing support 20, in particular a wire. The wire may be a metal wire, in particular a metal wire of a fixed diameter. The three-body polishing makes it possible to obtain a finer surface finish and a lower roughness compared to two-body polishing, in which the abrasive is fixed to the polishing support and rubs against the surface. In order to obtain the desired orientation of the residual polishing marks 61, i.e. to avoid an orientation along the axis A1, - avoiding back and forth grinding movements along the axis A1 of the mortise, as conventionally performed in standard and conventional processes for obtaining a straight hole; - conversely, by choosing a rotational movement of the tenon around the grinding support 20, i.e. around the axis A1, It is necessary to do so.

[0104] Furthermore, to obtain a uniform surface finish across the entire height of the hole and a hole that remains straight and / or cylindrical (as opposed to an olive cut hole), the tenon stone must be maintained straight relative to the abrasive support, i.e., with its axis A1 parallel to the surface of the abrasive support 20, so the stone must be prevented from tilting and / or the axis of the stone hole must not have a non-zero angle relative to the abrasive support.

[0105] To simultaneously meet these various requirements, as shown in Figure 2, the stone 1 is mounted on a grinding support 20, which is uniformly coated or filled with abrasive material 21. A force applied to the grinding support 20 presses the stone against a roller or drum 31, which acts as a contact surface and a means for rotating the stone. During the grinding step, the tenon stone 1 is thus driven against the grinding support 20 by (rolling) contact of its outer circumferential surface 7. To ensure proper driving and high-speed rotational movement and to prevent the stone from tilting, grooves 32 (or slots 32) are formed on the roller, the width, depth, shape and pitch of the grooves being judiciously selected.

[0106] The groove width is selected to provide good stone guidance by preventing the stone from tilting and is essentially determined by the stone's thickness, taking into account the specific gap. Typically, the groove width La is at least 50 μm greater than the stone's nominal thickness e, e.g., 80 to 100 μm greater. The groove depth p must allow for good stone guidance and good positioning of the wire on the roller, with a specific gap j1 between the wire and the roller's outer surface, typically at least 200 μm, and particularly between 200 and 400 μm. For example, for a stone with a diameter of 1.2 mm and a 0.2 mm hole, the groove depth p may be 0.12 mm. The groove profile preferably has a rectangular shape (having a U-shaped or rectangular profile in a longitudinal plane passing through the axis A2), particularly without rounded edges or a chamfered groove bottom, to make it easier to properly hold the stone in its vertical position relative to the roller 31.

[0107] The groove pitch may be zero, i.e., each stone may be placed in an individual groove perfectly perpendicular to the axis of the roller. However, manufacturing grooves that are spiral, i.e., have a non-zero pitch, is more advantageous in industrial terms, since it allows the stones to be gradually advanced along the roller as it rotates. The groove pitch may be at least equal to the groove width La, typically 1.5 times the groove width La, e.g., 0.6 mm for a 0.4 mm groove width. The pitch also determines the total distance the stone covers the roller. It is advantageous to select the smallest possible pitch to maximize the distance and time over which processing or polishing is performed. The diameter of the polishing support is selected according to the diameter of the stone hole, particularly to maintain good stiction resistance and limit the tendency of the stone to tilt, while leaving a gap j2 between the stone and the polishing support 20. Typically, the gap j2 ranges between 5 μm and 20 μm, e.g., 10 μm.

[0108] The axis of the grinding support must be oriented very precisely with respect to the groove. In particular, the axis of the grinding support must be perpendicular (or as close as possible to perpendicular) to the orientation of the groove. This requires that the angle of the helix of the slot be precisely offset. The required setting accuracy for this is <0.1°. For this reason, the grinding machines or equipment used to carry out such grinding have a specific structure with means that allow this specific setting. This means inclining the axis A2 of the roller with respect to the axis A3 of the grinding support, which axis A3 is parallel to the axis A1 of the mortise during grinding.

[0109] As shown in FIG. 4, the offset angle, designated α, can be determined with precision. α=atan(pa / (π×dr)), where dr is the diameter of the roller and pa is the pitch of the slot 32. The offset angle α corresponds to the angle of the helix of the slot 32. In other words, the axis A3 of the abrasive support and the axis A1 of the mortise must be perpendicular to the tangent of the helix of the slot 32. Alternatively, the axis A3 of the abrasive support and the axis A1 of the mortise must be perpendicular to the contact plane of the helix of the slot 32 at the point of contact between the mortise and the slot 32. This makes it possible to obtain a straight or cylindrical hole with a uniform roughness along the hole and with main machining striations of a substantially perpendicular radial orientation (relative to the axis A1).

[0110] As an example, for a roller diameter of 250 mm and a slot pitch of 0.6 mm, the offset angle is 0.044°. More generally, the helix preferably has a helix angle of less than 0.1°, or even less than 0.05°. This requires considerable setting accuracy. In practice, a first setting is performed based on the theoretical value, followed by a precision setting (on the order of hundredths of a degree) to remove any traces of the olive cut from the resulting stone (i.e., to keep the hole as cylindrical as possible, i.e., to minimize the difference in diameter between the center and the edge of the hole).

[0111] For a proper implementation of the method according to the invention, it is important that the axis A1 of the hole 5 in the tenon 1 is parallel to the axis A3 of the grinding support and / or that the angle between the axis A1 of the hole in the tenon and the axis A3 of the grinding support is as small as possible, in particular less than 0.5°. This requires great precision when setting the offset angle between the axis A3 of the grinding support and the axis A2 of the drum 31.

[0112] At first glance, the above-described method appears similar to the olive cut method, since the grinding method according to the invention is carried out with a roller machined with spiral grooves against stones mounted on a grinding support, allowing each stone to advance during grinding. However, there are a number of significant differences between the two. The purpose of olive cutting is to locally machine the hole, especially its emerging edge, to obtain a rounded contour (the purpose of olive cutting is to minimize the contact surface area between the stud and the mortise). This makes olive cutting a machining method that differs from grinding. The amount of material removed during olive cutting is significant, and the minimum diameter of the hole typically increases by several micrometers during olive cutting. In the case of olive cutting, the difference between the minimum diameter of the hole before and after olive cutting is typically 2 μm, and is even greater at the edge of the hole (the edge is determined along the axial direction of the stone). Therefore, olive cutting allows the minimum diameter of the hole to be closer to its nominal dimension. In contrast, in the case of the grinding method according to the invention, the diameter of the mortise is at its nominal value before the grinding step carried out during the stone manufacturing process. It is estimated that the difference in diameter between (i) the surface finish before carrying out the grinding method and (ii) the surface finish after carrying out the method is less than 0.1 μm. In other words, the purpose of the polishing method of the present invention is to remove as much material as possible, thereby reducing the peak-to-valley height of the scratches formed during the drilling and / or enlarging operations, thereby reducing the roughness, smoothing out any irregularities, and orienting the roughness in a direction that is beneficial for the movement of the part pivoting and guided by the mortise. - The angle between the abrasive support and the orientation of the groove is accentuated rather than cancelled out when the olive cut is made, typically around 5° to 10° or even 30°, which allows the stone to be tilted relative to the axis of the abrasive support to soften the edge corners at the end of the hole and create a rounded profile inside the hole. Precise control of the angle is not critical in the olive cut. For this reason, in the olive cut method, the axis of the hole in the tenon is not parallel to the axis of the grinding support, but has a significant inclination, for example at an angle of about 5° to 10°. - In addition, in the olive cut method, the intersection of the roller cylinder with the vertical plane containing the abrasive support forms an ellipse, i.e. the stone "rises" on the first half of the roller and "descends" on the second half of the roller, the slope switching at the apex, thus making it possible to obtain a uniform and symmetrical profile. - In the olive cut method, the grooves are preferentially V-shaped instead of U-shaped or rectangular, as this makes it easier to tilt and bevel the stone. - With regard to the order of steps, the olive cut is performed after the recess has been machined, in order to obtain an olive cut centered directly relative to the emergent end of the hole and because it is easier to tilt the stone in the groove for holes of shorter length. In the polishing method according to the invention, on the contrary, it is easier to keep the stone straight in the groove for holes of greater length. For this reason, the polishing step of the hole is preferentially performed before any machining of the recess and before any polishing of the upper and lower surfaces. For this reason, the groove machining and polishing steps are preferably reversed in the polishing method according to the invention compared to the olive cut method.

[0113] As a result of the above, the manufacturing method of the tenon stone 1 of the watch movement 100 is as follows: (i) free abrasive particles 21 are used, which roll between the surface 6 of the mortise 5 to be ground and the grinding support 20; and / or (ii) the tenon stone 1 is driven in a rotational movement about the axis A1 relative to the abrasive support 20, which is pulled back towards the surface 6 of the mortise 5 to be polished, said pulling back allowing the effect of contact, direct or indirect (via abrasive particles) between the abrasive support 20 and the surface 6; This includes the first step of polishing.

[0114] If we ignore the velocity of the forward movement of the stone in translation along axis A1 relative to the grinding support, the movement of the stone relative to the grinding support can be considered as a rotational movement about axis A1.

[0115] As mentioned above, during the first step of grinding, the tenon stone 1 is held in position relative to the grinding support 20 by contact between the peripheral surface 7 of the tenon stone 1 and the bottom of the slot 32. By preference, the surface 7 extends parallel or substantially parallel to the first axis A1.

[0116] Preferably, as a result of the above solution, during the first step of grinding, the grinding support is a wire whose axis A3 is substantially parallel to the axis A1, and the angle between the axis of the grinding support A3 and the axis A1 of the hole in the stone is less than 0.5°.

[0117] Furthermore, as a result of the above solution, during the first step of polishing, the tenon stone 1 is driven in a straight spiral or rotational movement about the axis A1 relative to the grinding support 20, and / or - a helical movement with a helix angle of less than 0.5° is generated, and / or - the angle between the axis A1 and the axis of the abrasive support A3 is less than 0.5°, and / or The angle between axis A1 (or axis A3) and axis A2 is equal to the angle of the helix of slot 32.

[0118] An embodiment of a grinding machine for carrying out the grinding method according to the invention is described below with reference to Figures 3 and 4. Optionally, the grinding machine makes it possible to carry out the grinding method industrially on large batches of stones (thousands, even tens of thousands of stones) in a reproducible and repeatable manner. Optionally, the machine makes it possible to grind several stones simultaneously.

[0119] The main elements of one embodiment of the polishing machine are illustrated schematically in Figures 3 and 4. The polishing machine mainly comprises: - rollers 31 or drums 31, - a polishing support 20, and - Frame 39, Includes. The polishing machine also an actuator 40, including a motor, for rotating the roller relative to the frame 39 about the axis A2; a module 38 for supplying or depositing abrasives onto the grinding support 20, making it possible to supply abrasives to the contact points between the grinding support 20 and the holes 5 in the stone; - a distribution module 37, which transfers the stones successively onto the rollers; a module 36 for setting the tension F of the abrasive support 20, and a module 35, which sets the angle α between the axes A2 and A3, and a module 34 for adjusting the position of the abrasive support relative to the roller in order to maintain a constant distance between the abrasive support and the roller over the entire length of the roller; Includes.

[0120] The tension setting module 36 makes it possible to maintain the abrasive support at the correct tension to ensure that the contact force exerted by the stone on the roller is constant. The tension setting module 36 can be simply and effectively realized by adjustable weights fixed to the ends of the abrasive support and exerting a correct tension on the abrasive support.

[0121] It is also advantageous for the various stones to be treated to be distributed over the rollers at equal spatial distances to ensure a constant and equal force on each stone, and for this purpose the distribution module 37 may comprise, for example, clamps 33 to ensure such an even distribution.

[0122] For example, the roller dimensions are: - an outer diameter greater than 10 cm or approximately 25 cm, and - Length: about 28cm, These dimensions must be adjusted and / or optimized depending on the characteristics of the stone.

[0123] The module 35 that sets the angle α between the axes A2 and A3 is - the axis of the grinding support and therefore the axis of the hole in the stone, and - the orientation of the groove in which the stone to be treated is placed; This allows for very fine angle setting to ensure perpendicularity between the In a variant, the setting module 35 makes it possible to ensure perpendicularity between the axis A3 of the polishing support and the tangent of the slot spiral by setting the angle α. In another variant, the setting module 35 makes it possible to ensure perpendicularity between the axis A3 of the polishing support and the contact plane of the slot spiral by setting the angle α at the contact point between the tenon and the slot 32. In particular, the setting module 35 comprises a plate supporting the roller 31 and the actuator 40, which is settable relative to the frame 39 supporting the polishing support 20. The setting module 35 also comprises a rolling coupling that allows adjustment of the angle α with an accuracy of about 1 / 100°, or even <1 / 100°. The adjustment is performed, for example, by a mechanical sliding system that is part of the setting module 35.

[0124] The angle α is initially set to a theoretical value, particularly the theoretical value of the helix angle, after which the setting stone is manufactured. The angle is then adjusted if the manufactured mortise hole in the stone is not cylindrical, and / or if diameter variations are detected along the manufactured mortise hole, and / or if deviations (e.g., deviations greater than 0.5 μm) are detected along the manufactured mortise stone, and / or if significant portions of the mortise hole surface are not corrected (ground) by the method. The objective is to remove areas and traces of drilling or enlargement operations along the entire length of the mortise hole. When the axis A1 of the hole in the stone is parallel to the grinding support, the entire hole surface 6, from the lower surface 4 to the upper surface 2 of the stone, is ground uniformly or substantially uniformly.

[0125] When adjusting the abrasive support relative to the roller, it is important that the abrasive support contacts the hole in the stone. The position of the abrasive support, particularly the angle of its axis relative to the surface of the roller, does not need to be precisely set, provided that the abrasive support is guided by the stone and maintained in position by the tension applied to the abrasive support. The depth of the groove does not need to be too great to maintain the abrasive support away from the roller, but it must be sufficient to ensure proper guidance of the stone and to prevent vibration. What is important is that the force exerted by the abrasive support, which also allows for uniform abrasion, maintains the stone in proper contact with the bottom of the hole.

[0126] For example, the roller speed ranges between 800 and 1500 rpm, typically 1200 rpm. With a roller diameter of approximately 25 cm and a stone diameter of typically 1 mm, the result is a very high rotational speed of the stone, approximately 300,000 rpm or 5,000 rps (assuming the stone does not slide on the roller). The rotational speed is therefore much faster than the speed at which the stone advances on the abrasive support. For example, with a hole diameter of 0.2 mm, the velocity at the contact point between the abrasive support and the hole is 3.15 m / s in the radial direction perpendicular to the axis A1, while it is 9.2 mm / s in the axial direction relative to the axis A1—more than 300 times faster. The angle of the abrasive scratches relative to a plane perpendicular to the axis A1 is, in this case, approximately 0.2°, and is therefore negligible.

[0127] The velocity of the tenon 1 relative to the grinding support 20 in a radial direction perpendicular to the axis A1 at the point of contact with the grinding support 20 may be in the range between 1 m / s and 20 m / s, in particular between 1 m / s and 10 m / s.

[0128] Another advantageous factor in the reproducibility of the polishing method of the present invention is the consistent spacing between stones, which prevents them from colliding with each other during processing and ensures good separation of the stones on the roller. This ensures equal contact forces from stone to stone and along the roller. One solution to ensure good distribution is to use precise gripping means, particularly clamps, in the distribution module 37, which remove exactly one stone at a time, at consistent intervals, and then release the stone onto the polishing support and roller in the same manner. The polishing support advances at a very slow speed along axis A1 relative to the roller to advance the stone to the distribution module. The advancement speed is typically approximately the thickness of the stone per distribution period. If the module is set to distribute a stone onto the roller every 6 seconds and the stone thickness is 0.315 mm, the resulting forward movement speed of the polishing support is typically about 0.2 m / hour. The forward movement speed is not related to the structure of the tenon obtained by the manufacturing method. Said movement is only necessary to obtain advancement of the tenon outside the roller 31 in the described embodiment of the manufacturing method.

[0129] A reliable distribution module that ensures correct forward movement of the abrasive support and correct distribution of the stones is an advantageous element so that each stone has the desired surface finish in the mortise. Since verifying the surface finish is destructive and difficult or impossible to perform periodically on stones or stone samples during the stone manufacturing process, the implementation of the method must be robust and reproducible.

[0130] Needless to say, it is also possible to add cameras, display monitors, measuring means and results, parameter tracking means, man-machine interfaces, etc. to ensure the correct execution of the method (e.g. to check the height of the polishing support, the position of the clamps, and / or the correct distribution of stones on the roller).

[0131] When the polishing method is performed on a new stone shape, a setup and optimization step must be performed. Generally, there are interactions and influences that must be optimized between the roller speed, the polishing support tension (and therefore the applied force), the hole diameter, and the abrasive size.

[0132] More generally, a grinding machine 30 for grinding the mortise holes 5 of the mortise stones 1 of a timepiece movement 100 according to the invention comprises a drum 31 driven in rotation about an axis A2 and having a slot 32 forming a spiral around the drum 31, the slot 32 being - driving the tenon, - holding the tenon in position so that the axis A1 is perpendicular to the contact plane of the helix at the point of contact between the tenon and the slot, Do both.

[0133] The polishing method described above, in one embodiment, allows for the polishing scratches or striations on the mortise surface to be oriented radially at right angles to the axis A1 of the mortise 5. This orientation is highly desirable, since it matches the orientation of the movement of the parts guided in the stone, particularly the tenon, relative to the stone, and thus prevents a "file" effect that causes rapid wear of the tenon. On the other hand, the polishing method described above, in one embodiment, allows for the repetitive obtaining of low roughness values ​​of less than 5 nm under optimized conditions. Because the scratch orientation is radially at right angles to the axis A1, measuring the roughness at right angles is not appropriate, and the values ​​given are measured axially.

[0134] The above-described method is also applicable to tenons produced by other methods or method steps, such as stones produced by pressing and / or stones with recesses formed by laser processing and / or stones with other elements such as the interstitial areas described in patent application WO 2007 / 024900. The above-described method is also applicable to other watch parts containing holes, in particular cylindrical holes, such as tubes, for example ceramic or metal tubes, or to watch parts such as pinions.

[0135] More generally than described above, the method for manufacturing the watch part 1 may comprise the step of grinding or machining the hole 5 by abrasion with abrasive particles 21 which are free with respect to the machining support 20 and roll between the surface 6 of the hole to be machined and the machining support 20 housed in the hole, and / or by using abrasive particles which can detach from the machining support, the part being driven in a rotational movement about the axis of the hole relative to the grinding or machining support.

[0136] As a result of carrying out the above-described method and / or using the above-described machine, it is possible to manufacture a mortise stone 1 for a timepiece movement 100, which comprises a mortise 5, in particular a cylindrical mortise, having a first axis A1 and allowing the timepiece part to pivot or be pivoted around it. The mortise part comprises a surface 6 having primary abrasive-machining striations 61, in particular primary grinding striations, oriented radially and substantially perpendicular to the first axis A1.

[0137] The orientation of the scratches, that is the orientation of their length or their largest dimension, may be determined by inspecting the image and by using the surface texture identification means described above. The machining method described above does not control the number, shape or location of the machining scratches, but the method results in a preferred orientation that is substantially perpendicular to the axis A1 of the hole.

[0138] The primary machining and / or grinding streaks 61 advantageously have an average helix angle of less than 1° or less than 0.5°, or more generally - a plane of contact with every main scratch at every point of the main scratch; - a plane perpendicular to the axis A1; are parallel or form an angle between them of less than 1° or less than 0.5°.

[0139] In other words, the main machining and / or grinding marks 61 are preferably parallel or substantially parallel to a plane perpendicular to the axis A1, or in further words, the main machining and / or grinding marks 61 (or their tangents) form an angle of less than 1° or less than 0.5° with respect to a plane perpendicular to the axis A1.

[0140] Advantageously, the roughness Ra of the surface 6, in particular the roughness Ra of the surface 6 measured parallel to the first axis A1 or perpendicular to the main scratches 61, is less than 20 nm or less than 10 nm.

[0141] As a result of carrying out the above-described method and / or using the above-described machine, the profile of the surface 6 of the mortise 5 through a plane passing through the axis A1 is: - Straight line, or - convex as viewed from axis A1, with a deviation of less than 1 μm or less than 0.25 μm; may be.

[0142] According to the first use, as shown in FIG. 5, the tenon stone 1 is - Driven into the frame 99 of the clock movement 100, and - The mortise hole 5 receives a part 98 such as a clock stem. It is intended that Watch parts, among others, - balance wheel, or - Ankle set, or - Escape wheel, or - the final gear, such as the second wheel, minute wheel, third wheel or seconds wheel, or - Gears of the automatic winding drive train, may be.

[0143] According to the second use, as shown in FIG. 6, the tenon stone 1 is - Clock parts such as clock stems are inserted into 98, - in the mortise hole 5, to receive the tenon of the frame 99 of the watch movement 100 or other watch part; It is intended that the timepiece part 98 or other timepiece part may be a wheel of a final gear, such as a center wheel or a minute wheel or a third wheel or a seconds wheel, among others.

[0144] In the first and second uses, the two tenons may be used to guide the watch part relative to the frame 99 or relative to other watch parts, if desired.

[0145] According to a third use, the tenon 1 is intended to receive in the mortise hole 5 the post of a watch part 98, such as a lever. In this use, the tenon is used as a runner and its outer surface 7 is intended to roll on another watch part. In this case, the outer surface 7 is - Rolling in the grooves of the drum while the stone is being produced, and - Rolling on watch parts after manufacturing and while they are in use; It is contemplated that the outer surface 7 may not be cylindrical. For example, the outer surface 7 may be generally frusto-conical. Furthermore, the outer surface 7 may have a complex profile, such as a convex profile, a concave profile, or a cam profile, in a plane perpendicular to the axis A1.

[0146] More generally, the invention also relates to a watch part, such as a tube, for example a ceramic or metal tube, comprising a hole, in particular a cylindrical hole, or a watch part, such as a pinion, the mortise comprising a surface having primary abrasive-machining striations, in particular primary grinding striations, oriented radially, substantially perpendicular to the axis of the hole.

[0147] The present invention also relates to a watch movement 100 comprising at least one of the above-mentioned tenon stones, in particular at least two of the above-mentioned tenon stones, and / or comprising a watch part 98 comprising the above-mentioned tenon stone 1, and / or comprising the above-mentioned part.

[0148] The present invention also provides - at least one of the tenons mentioned above, and / or - the above-mentioned watch parts, and / or - the above-mentioned watch movement 100, The present invention relates to a timepiece 200, particularly a wristwatch, including a timepiece 200.

[0149] Measuring the finish on the inner surface 6 of the mortise 5 presents a two-fold challenge. - succeed in accessing surface 6, the finish of which needs to be measured, which is very difficult to achieve due to the shape of the hole, and then - Measure its roughness.

[0150] In the following, it will be explained how to prepare the stone in a first step so that the finish of the friction surface 6 can be measured in a second step.

[0151] For measuring roughness, laser scanning confocal microscopy appears to be particularly advantageous because it appears to be suitable for concave surfaces. Laser scanning confocal microscopy allows accurate measurement of surface roughness even at very low magnifications in accordance with the ISO 25178 (surface area roughness) and ISO 4287 (linear roughness) standards.

[0152] In the context of this specification, it is preferable to measure linear roughness rather than areal roughness due to the preferential orientation of the roughness. This is because the measurement of areal roughness involves taking an average over a surface area, which is relevant when the surface finish is uniform and non-directional, but is less appropriate for the present application, which involves the concept of roughness orientation. For this reason, it is appropriate to consider the linear roughness Ra, i.e., the arithmetic mean difference of the profile being evaluated.

[0153] The preferential orientation of roughness can be quantified by considering the parameters Str and Std. The parameter Str, also known as "isotropy," measures the uniformity of the surface texture and, based on the definition of the standard, takes an anonymous value between 0 and 1. If a surface has identical characteristics in all directions (an isotropic surface), the value of Str will approach 1, while a highly anisotropic or textured surface will have an Str value close to 0.

[0154] If the surface is anisotropic (Str value close to 0), it is advantageous to identify the preferred texture direction, represented by the parameter Std. A useful tool for this is the polar spectrum, i.e., the integrated Fourier spectrum in polar coordinates. The angle corresponding to the strongest spectrum corresponds to the dominant texture direction, and the dominant direction of the spectrum gives the parameter Std, which is the counterclockwise angle of that dominant direction from the reference axis of the image. For this reason, it is important to always orient the image in the same way relative to the reference axis. In addition, it is preferable to perform measurements excluding the edges of the image or part, align the surface to eliminate shape effects, and provide an appropriate acquisition pitch and square image size, if possible.

[0155] The preferred orientation of the roughness, quantified by the parameters Str and Std, in particular the preferred orientation of the texture represented by the parameter Std, which is the counterclockwise angle of the main direction from the reference axis of the image, corresponds to the orientation of the main striations that determine the roughness of the surface. In other words, for example, when the counterclockwise angle of the preferred orientation of the texture represented by the parameter Std is substantially perpendicular to the first axis A1, the main striations are considered to be oriented radially, substantially perpendicular to the first axis A1.

[0156] To measure roughness, an instrument equipped with pinhole confocal optics, such as the Keyence VKX-1100, can be used. The main parameters are vertical and lateral resolution. The 50x lens with a 0.95 aperture used in the instrument described above allows for optimal optical resolution at a sufficient working distance to measure the area of ​​interest on the stone prepared using the method described below. Measurements are taken in the central area of ​​the stone. The length of the segments is selected according to the ISO 4287 standard; for example, 30 different segments are measured consecutively, with each segment cut into five subsegments according to the standard to minimize the influence of the contour shape.

[0157] To obtain a roughness-specific measurement, the measured segments are oriented perpendicular to the residual grinding scratches 61 and / or perpendicular to the preferred direction of the texture, represented by the parameter Std. In other words, the measured segments are oriented in a transverse radial direction when the residual machining or grinding scratches 61 are oriented in an axial direction (as after enlargement), and the measured segments are oriented in an axial direction when the residual machining or grinding scratches 61 are oriented in a transverse radial direction (as after the grinding method according to the invention described above).

[0158] The roughness values ​​obtained will of course vary depending on the measurement instrument and technique used. All values ​​presented herein were obtained using a laser scanning confocal microscope at 50x magnification, measuring 30 segments and calculating the roughness Ra.

[0159] To take the measurements, for example, a semi-stone from the preparation described below is placed in a vise, after which the measurement area can be successively focused with different lenses until a clear image is obtained, for example at 50x magnification. A resolution image of 2048 x 1536 pixels can be used, with a pitch of 0.10 μm between segments. The segment length can be 65 μm, with 30 lines spaced 2 μm apart. The roughness is measured in a direction perpendicular to the residual machining or grinding marks. According to the standard, the measurement of roughness Ra is only applicable if the ratio between the standard deviation and the obtained value Ra is strictly less than 0.2.

[0160] Tests carried out on several batches of polished stone obtained by various methods highlight that, under standard magnification, residual polishing scratches are axially oriented, and therefore the lines of measurement are oriented in the perpendicular radial direction. The measured roughness was 25.5 ± 5.0 nm.

[0161] According to the polishing method of the present invention, the residual polishing scratches were oriented in a perpendicular radial direction, the line of measurement was oriented in the axial direction, and the measured roughness was 4.0±1.6 nm.

[0162] In both cases, the surface texture is emphasized, with comparable Str (isotropy) values ​​close to 0. However, the isotropy (Str) is still strictly greater than 0, in particular greater than 1%. For the standard magnification method, the value is approximately 20%, whereas for the method according to the invention it is less than 10%, even less than 3%. In particular, the method according to the invention makes it possible to obtain roughnesses Ra of less than 5 nm, with a texture preferred orientation of 90° + / - 0.5° relative to the direction parallel to the hole axis, and isotropies greater than 1% and less than 10%, in particular less than 3%. The difference is particularly evident from the Std values ​​on the polar spectra, where the Std texture preferred orientation was 7° and 90.1° for the standard magnification method and the method according to the invention, respectively.

[0163] The above-described measurement method can be used for any type of stone, including olive-cut stones. As mentioned above, the purpose of olive-cutting is to obtain a rounded mortise profile rather than a straight mortise profile. The edges of the hole are rounded, and the deviation (the difference in diameter between the center and end of the hole) is measurable and is at least 3 μm, more typically at least 5 μm. The deviation value is not specified in the design because there has previously been no way to measure this feature; the presence of an olive cut is usually observed only by visual inspection, due to the elliptical shape of the reflection in the hole. The deviation value also depends on the diameter and length of the hole. In contrast, when a typical profile measurement is performed on a stone according to the present invention, the edges of the hole are well defined, and the deviation of the hole profile is 0.175 μm. In a measured batch of 40 stones, the measured deviation was between 0.1 and 0.2 μm over a 150 μm circumference around the hole opening. In finished stones, the deviation may be smaller because the hole length may be reduced by a possible grooving operation.

[0164] The above-described measuring method may also be applied to other watch parts containing holes, such as tubes, for example ceramic or metal tubes, or watch parts such as pinions.

[0165] The shape of the stone makes it very unnatural to quantitatively measure the finish of the surface 6 of the mortise hole 5. The surface can only be viewed directly by tilting the hole to a significant degree, making it difficult to take measurements of the slope and / or limited surface.

[0166] Thus, one embodiment of the step of preparing the tenon 1 involves removing a first part of the tenon 1, including part of the outer surface 7 and part of the volume between the mortise surface 6 and the outer surface 7, together with part of the surface 6 of the mortise 5, to obtain a second part of the tenon 1. This step of preparing the stone allows for rapid and reproducible obtaining of elements that can be measured with direct and unobstructed access to the area of ​​the surface 6 to be measured. The illustration of FIG. 1 provides a good representation of the second stone part obtained by this preparation method. In particular, the first part of the tenon can be removed through a plane passing through the axis A1 of the tenon 5 or through a plane parallel to the axis A1 of the tenon 5. The aim is to allow direct access to the entire contour of the mortise surface in the axial direction, in particular with a light or laser beam perpendicular or substantially perpendicular to said contour.

[0167] It might seem that the only way to gain access to the stone mortises is to strike them with a tool to break them and form fragments with the mortise surface intact, but such a method is highly random and unrepeatable, making it unsuitable for routine inspection.

[0168] The first method involves removing material from one part of the stone, particularly by abrasion, and is particularly advantageous when a certain amount of stones of the same type must be tested, for example by testing 20 stones randomly from a batch of 1000 stones.

[0169] The quality of the removed part is not important, since it is not what is being measured. However, it is necessary to ensure that the cutting method does not alter the sample in the hole. A finish grinding method is suitable, for example, because it allows the part to be immediately prepared by cutting. To prevent the presence of the coating resin in the hole, especially if a coating resin is used, it is beneficial to attach the stone to a wire, preferably a nylon or other polymer thread, with a diameter slightly smaller than the diameter of the hole (e.g., 10 μm smaller), to place the stone at the same height and protect the mortise. It is also possible to use wire that leaves a gap of more than 10 μm and melt the end to seal the stone hole at the end, ensuring that there is no contamination in the hole. Metallic wire, such as brass wire, can also be used, especially for wires with small diameters, e.g., diameters smaller than 0.2 mm. In the case of metal wire, it is important to properly adjust the wire to the diameter of the hole to prevent the coating resin from penetrating the hole and making subsequent measurements impossible.

[0170] Once coated, the stone can be simply finish-ground until there is a height difference between the bottom of the hole and the cut or removed surface, e.g., 0.2 mm, about the radius of the hole, so that the measuring equipment can easily access the area to be measured. The wire can be maintained in place during the finish-grinding step and removed just before the stone is cleaned and measured. Stones with surfaces to be measured at comparable heights can be aligned in a configuration well suited to automated measurement. A series of dozens, or even hundreds, of stones can be automatically measured in this manner.

[0171] As a result, the sub-step of assembling multiple tenons 1 can be carried out before removal.

[0172] The second technique is particularly suitable for preparing individual stones, for example unique stones, especially stones removed from a movement blank, and consists in carrying out removal by fragmentation.

[0173] The procedure allows for simple and repeatable cutting of watch stones, especially synthetic rubies, to access their internal walls for the purpose of measuring roughness. The principle is to use a diamond tool, such as a diamond chisel or diamond-tipped tool, to make a notch in one of the upper or lower faces of the stone (e.g. the non-recessed face), initiating a fracture that makes the stone breakable by exposing it to a small impact.

[0174] Before cutting, it is ensured, for example, by optical microscopy, that the stone is in a good state of cleanliness. If necessary, dust is removed from the stone and the stone is cleaned, for example, by washing in an aqueous phase or solvent. The flat side of the stone is first placed facing the operator and a notch is made using a diamond tool. The notched stone is then positioned so that a small impact can be applied, for example, by a hard metal riveting punch placed on a driving tool. A slight blow applied to the rod of the driving tool, for example, by a watchmaker's hammer, can break the stone at the start of the crack. For this step, the stone may be held by an attachment or a vice or other support or means suitable for holding the stone in its position.

[0175] The two half-stones are then recovered, possibly cleaned to remove any residue or particulate matter, and then measured. It is emphasized that this scoring and impact breaking method produces far less particulate matter and debris than traditional wire cutting. This second method is also repeatable and does not rely on the dexterity of the person performing it.

[0176] Alternatively, the stone or batch of stones may also be cut with a saw or wire, but this third approach is less preferred due to the risk of chips being formed by cutting in the area close to the surface to be measured.

[0177] Thus, generally speaking, the method makes it possible to determine the roughness of the surface 6 of the mortise hole 5 of the mortise stone 1. a first step of preparing the tenon stone 1, comprising removing a first part of the tenon stone 1, including a part of the surface 6 of the mortise hole 5, in order to obtain a second part of the tenon stone 1; and then a second step of measurement carried out on the surface 6 of the mortise hole 5 located in the second part of the mortise stone 1; Includes.

[0178] Logically, since the preparation of the stone, in particular the removal of the first part of the tenon, does not modify the tenon surface located in the second part of the tenon, the roughness measurements obtained are in fact indicative of the surface finish of the mortise obtained following the manufacture of the watch part, in particular following machining and polishing.

[0179] The preparation method described above can be used for all types of stones, including olive-cut stones. The preparation method is also applicable to other watch components that contain holes, such as tubes, e.g., ceramic or metal tubes, or watch components such as pinions.

[0180] The present invention also relates to the cleaning of the watch part, and for this reason an embodiment of the step of cleaning the watch part 1 and the machining support 20 while the machining support is housed in the hole of the watch part 1 is described in detail below.

[0181] The cleaning step is advantageously carried out in the method for manufacturing a tenon stone described above, which method also includes a step of polishing the mortise.

[0182] However, more generally, the cleaning step can be carried out in any method of manufacturing a watch part comprising a hole, the method comprising: - machining the hole by abrasion using abrasive particles, in particular diamond particles, which are free with respect to the machining support and roll between the surface of the hole to be machined and the machining support accommodated in the hole, and / or using abrasive particles which can be detached from the machining support, Includes. Consequently, the step of washing is also applicable to the method of manufacturing olive cut stones after the step of machining the olive cuts.

[0183] In these methods, some abrasive remains on the machining support and on the stone when the stone 1 has completed its passage through the rollers 31. Investigations carried out in the preparation and measurement methods have shown that the presence of residual abrasive often causes problems when the stone is detached from the wire, i.e. when the stone is removed from the machining support.

[0184] This is because abrasive particles can become lodged in the mortise and cause axial scratches when the stone is removed from the wire or when the part is removed from the machining support. These scratches or scratches can adversely affect the surface finish of the hole by causing significant axially oriented roughness and / or disrupting the evenness of the olive cut rounding, which may be undesirable.

[0185] If no cleaning step is performed, axial scratches are often observed. These scratches have a low density and low depth, but can be very noticeable. In all cases, the roughness is worsened, and the olive cut of the surface finish is partially or even completely removed. In this case, since the hole has already been brought to its final dimensions by the olive cut, which involves the removal of a large amount of material, significantly more than the depth of the residual enlargement scratches, this is certainly a deterioration that occurs after the olive cut and not a residual effect of the enlargement method. In addition, the observed scratches have a symmetrical shape and are superimposed on the characteristic contour of the olive cut, with deviations typically greater than a few microns.

[0186] The addition of a step of cleaning the machining support and stone to remove the abrasive before the stone is removed from the wire makes it possible to prevent damage to the polished or machined surface. This cleaning or cleaning can be carried out in various ways, for example in an aqueous medium or solvent, with or without detergent, with or without ultrasound, or by spraying with steam, or by cleaning with water or solvent. This cleaning can be carried out directly in a tool that cleans the stone directly at the exit of the roller 31, or it can be carried out outside the tool after the machining support has been removed. Preferably, cleaning is carried out using a flow of liquid to remove the abrasive particles used during machining or polishing. The liquid can be a cleaning solution, in particular an aqueous, alcoholic or oily solution.

[0187] Additionally or alternatively, the cleaning step may comprise immersing the watch part 1 and the machined support 20 in a cleaning solution, which may comprise emitting ultrasound waves into the cleaning solution.

[0188] Additionally or alternatively, the cleaning step may involve spraying a cleaning solution onto the watch part 1 and the machining support 20.

[0189] Additionally or alternatively, the cleaning step may include spraying with gas or steam.

[0190] The cleaning system 84 may be positioned immediately after the roller. This allows the cleaning step to be performed directly on the machining machine, in particular on the grinding machine where the step of machining the hole by abrasion was performed. The cleaning system 84 may be part of the machining machine 30. The cleaning system allows the stone and the machining support to be cleaned or cleaned immediately after grinding, olive cutting, or other machining. The cleaning system advantageously includes nozzles 83 and / or channels for spraying a cleaning liquid, such as a cleaning solution. Preferably, these nozzles and / or channels are arranged to form jets directed both in the direction of the stone's forward movement on the machining support and in the direction opposite to the forward movement, thereby first cleaning both sides of the stone and then at the end of the cleaning system in the direction of the stone's forward movement as it exits the cleaning system. The cleaning system is advantageously designed to form a housing 80 from two parts 81, 82 that can be partially opened, for example, to install a new machining support or to set the position of the cleaning system relative to the machine support and the rest of the machine. As a result, the cleaning system 84 takes the form of a housing 80 as shown in Figure 7. The assembly formed by the watch part 1 and the machined support 20 can pass completely through said housing 80. For this reason, the housing 80 has a passage for the machined support.

[0191] Alternatively, the washing step may be - 1 watch part, a machined support 20; This may also be performed after the assembly consisting of the watch part 1 and the machining support 20 has been removed from the machining machine on which the step of machining the hole by abrasion was performed. In such a case, the assembly consisting of the watch part 1 and the machining support 20 is removed from the machining machine, after which the assembly consisting of the watch part 1 and the machining support 20 is cleaned, after which the watch part 1 is removed or separated from the machining support 20, in particular the machining support 20 is removed from the hole in the watch part 1.

[0192] More generally, the method for producing the watch component 1 as described above comprises: - machining the hole 5 by abrasion using abrasive particles 21 that are free with respect to the machining support 20 and roll between the surface 6 of the hole to be machined and the machining support 20 housed in the hole and / or using abrasive particles that can be detached from the machining support, and then - cleaning the watch part 1 and the machining support 20 while the machining support is housed in the hole, and then - removing the machined support from the hole; may include:

Claims

1. A method for manufacturing a timepiece part (1), in particular a mortise stone (1), including a hole (5), comprising: a step of machining the hole (5) by abrasion using abrasive particles (21), in particular diamond particles, which are free with respect to a machining support (20) and roll between the surface (6) of the hole to be machined and the machining support (20) housed in the hole, and / or using abrasive particles which can be detached from the machining support, then a step of cleaning the watch part (1) and the machining support (20) while the machining support is housed in the hole, then removing the machined support from the hole; Including, Manufacturing method.

2. the washing step comprises the use of a washing solution, in particular an aqueous or alcoholic or oily solution; The method of claim 1.

3. The cleaning step comprises immersing the watch part (1) and the machined support (20) in the cleaning solution; The method of claim 2.

4. The immersion includes applying ultrasound waves into the cleaning solution. The method of claim 3.

5. The cleaning step comprises spraying a cleaning solution onto the watch part (1) and the machining support (20), The method of any one of claims 1 to 4.

6. The cleaning step includes spraying with gas or steam. The method of any one of claims 1 to 5.

7. the cleaning step is carried out on a machining machine, in particular on a grinding machine, on which the step of machining the hole by abrasion was carried out; The method of any one of claims 1 to 6.

8. The washing step comprises: The watch component (1), The machined support (20) and is removed from a machining machine on which the step of machining the hole by wear was performed, The method of any one of claims 1 to 6.

9. the cleaning step is carried out in a housing (80), the assembly consisting of the watch part (1) and the machined support (20) passing completely through said housing; The method of any one of claims 1 to 8.

10. The method according to any one of claims 1 to 9 comprises hardware means (80, 81, 82, 83) for carrying out said step of cleaning of the watch part (1) while the machined support is housed in the hole of the watch part (1), in particular: a housing (80), for example formed by two parts (81, 82) movable relative to one another as a whole, and / or having a passage for said machined support; Nozzles 83 and / or channels for spraying the cleaning solution; Including, A cleaning system (84).

11. - comprising hardware means (20, 31, 34, 35, 36, 37, 38, 39, 40, 84) for implementing the method according to any one of claims 1 to 9, in particular a washing system (84) according to claim 10, A machining system (30).

12. Obtained by carrying out the method according to any one of claims 1 to 9. Clock parts (1), especially mortise stones (1).

13. The watch component (1) according to claim 12, Clock movement (100).

14. A timepiece component according to claim 12 and / or a timepiece movement (100) according to claim 13, Clock (200).

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