CH711214A2 - A method of manufacturing a part having a browning step. - Google Patents

Abstract

The invention relates to a method for manufacturing a part, in particular a balance shaft, intended to be welded, comprising a burnishing step making it possible to form a perpendicular wall (45) with respect to the face (41 ') undergoing the burnishing intended to perfect the flatness of the face which must be welded. The invention also relates to a method of manufacturing a watch component.

Description

Field of the invention

The invention relates to a manufacturing method comprising a modified browning step and, more specifically, such a step for improved surface flatness.

Background of the invention

It is known from document PCT / EP 2015/061 774 to form a watch component from a part comprising a material based on silicon or ceramic which is directly welded by electromagnetic radiation to another piece such as, for example, for example, a metal or a metal alloy.

In the context of this development, it appeared important that the gap between the parts should not exceed 0.5 micrometer or they could not be welded.

Summary of the invention

The object of the present invention is to overcome all or part of the disadvantages mentioned above by proposing a new manufacturing method with at least one contact surface having an improved flatness allowing the assembly of parts by welding.

For this purpose, according to a first embodiment, the invention relates to a method for manufacturing a part comprising the following steps: bring a bar; detaching the bar to form at least one diameter having a substantially vertical surface and a substantially horizontal surface; browning the substantially vertical surface to increase its hardness and improve its surface condition, characterized in that, during the burnishing step, the burnisher is moved along the substantially vertical surface until the burnisher also enters contact with the substantially horizontal surface to polish said substantially horizontal surface when the burnisher is remote from said substantially vertical surface.

Advantageously according to the invention, the manufacturing method provides a face with a perfectly flat and perpendicular surface guaranteeing its welding.

According to other advantageous variants of the invention: the cutting step also forms an oblique wall between the substantially vertical surface and the substantially horizontal surface to avoid forming a burr during contact of the burnisher against said substantially horizontal surface; the cutting step also forms a curved wall around said substantially horizontal surface to avoid forming a burr during contact of the burnisher against said substantially horizontal surface.

In addition, the invention relates to a method of manufacturing a watch component comprising the following steps: forming a first metal-based part from the method according to one of the preceding variants and a second part; mounting a surface of the first piece on a surface of the second piece; welding, by electromagnetic radiation of the laser type, the surface of the first piece mounted on the surface of the second piece to secure them.

[0009] According to other advantageous variants of the invention: the second piece is silicon-based or ceramic-based; the second piece further comprises at least a partial coating of metal, silicon oxide, silicon nitride, silicon carbide or a carbon allotrope; the first piece comprises an alloy of iron, a copper alloy, nickel or one of its alloys, titanium or one of its alloys, gold or one of its alloys, silver or one of its alloys, platinum or one of its alloys, ruthenium or one of its alloys, rhodium or one of its alloys or palladium or one of its alloys.

Brief description of the drawings

Other features and advantages will become apparent from the description which is given below, for information only and not limiting, with reference to the accompanying drawings, in which: <tb> fig. 1 <SEP> is a perspective view of a sprung balance resonator; <tb> fig. 2 <SEP> is a perspective representation of a hairspring according to the invention; <tb> fig. 3 <SEP> is a perspective representation of a balance shaft according to the invention; <tb> fig. 4 <SEP> is a sectional representation of an assembly according to PCT / EP 2015/061 774; <tb> figs. 5 and 6 <SEP> are sectional representations of a burnishing according to a first embodiment of the invention; <tb> figs. 7 and 8 <SEP> are sectional representations of a burnishing according to a second embodiment of the invention; <tb> fig. 9 <SEP> is a sectional representation of an assembly according to the invention.

Detailed Description of the Preferred Embodiments

The invention relates to a component formed using a workpiece whose material has no usable plastic field, that is to say with a very small plastic area, with a second part comprising the same type of material or another type of material.

This component has been devised for applications in the watchmaking field and is made necessary by the growing share of fragile materials such as those based on silicon or ceramic. It is possible, for example, to form a case, a dial, a flange, an ice, a telescope, a pusher, a crown, a caseback, a needle, a bracelet, a spiral, a pendulum, an anchor, a bridge, an oscillating weight or even a mobile like an escape wheel totally or partially based on fragile materials.

Preferably, the silicon-based material used for producing the compensating balance spring may be monocrystalline silicon whatever its crystalline orientation, doped monocrystalline silicon whatever its crystalline orientation, amorphous silicon, porous silicon, polycrystalline silicon, silicon nitride, silicon carbide, quartz irrespective of its crystal orientation or silicon oxide. Of course other materials can be envisioned as a glass, a ceramic, a cermet, a metal or a metal alloy. In addition, the first silicon-based part may further optionally comprise at least one partial coating of silicon oxide, silicon nitride, silicon carbide or a carbon allotrope according to the intended applications of the watch component.

For simplicity, the explanation below will be focused on an assembly between a balance spring and a balance shaft. In fig. 1, we can see a resonator 1 in which the hairspring 5 is used to thermally compensate the whole of the resonator 1, that is to say all the parts and in particular the balance 3 mounted on the same shaft 7 balance. The resonator 1 cooperates with a maintenance system such as, for example, a Swiss lever escapement (not shown) cooperating with the pin 9 of the plate 11 also mounted on the shaft 7.

A compensating hairspring 15 is better visible in FIG. 2. It comprises a single blade 16 wound on itself between an inner coil 19 formed in form with a ferrule 17 and an outer coil 12 having an end 14 to be punctured. As shown in fig. 2, in order to improve the isochronism of the resonator in which the spiral 15 is used, the latter comprises an internal turn 19 comprising a Grossmann type curve and an outer turn 12 comprising a thickened portion 13 relative to the remainder of the spiral 15, Finally, it can be seen that the ferrule 17 comprises a single band extending in a substantially triangular shape so that the ferrule shows an elastic character when it is adjusted on the axis, in particular to allow its centering relative to the latter.

A shaft 27 is better visible in FIG. 3. It comprises in particular several diameters 22, 24, 26 for respectively receiving the hairspring, the balance and the plate. As shown in fig. 3, the diameter 22 comprises a cylindrical rod 21 bordered in its lower part by a bearing surface 23.

As illustrated in FIG. 4, the diameter 22 is intended to receive, between the rod 21 and the bearing surface 23, the ferrule 17 of the spiral 15. More specifically, the inner face 20 of the collar 17 is elastically pressed against the outer surface of the rod 21 and the lower face 18 of the shell 17 is pressed against the bearing surface 23. Finally, as visible under the reference 28, the rod 21 and / or the bearing surface 23 are welded to the shell 17 as taught in document PCT / EP 2015/061 774 .

However, as part of the development of the teaching of document PCT / EP 2015/061 774, it quickly emerged that the gap between the pieces should not exceed 0.5 micrometer or they would not can not be soldered.

The method according to the first embodiment of the invention therefore comprises a first step intended to provide a bar adapted to undergo a bar turning. The example relates to an assembly between a spiral and a balance shaft, the bar may be based on metal or metal alloy.

The second step is intended to décolleter different diameters necessary to form the shaft 47 balance and in particular the diameter 42 adapted to receive the shell 17 of the spiral 15. In FIG. 5, it can be seen that the diameter 42 has a substantially vertical surface 41 forming a blank of the rod and a substantially horizontal surface 43 forming a blank of range.

The process is continued with a third step intended to brown the substantially vertical surface 41 to increase its hardness and improve its surface state and thus form the rod 41. Advantageously according to the invention, during the browning step, the burnisher 30 rotatably mounted according to B is moved in the direction A in contact with its main face 31 against the substantially vertical surface 41 also rotatably mounted according to C as visible in fig. 5.

In addition, during the browning step, the burnisher 30 continues its movement along the direction A 'until the burnisher 30 also comes into contact with its side face 32 against the substantially horizontal surface 43. then understands that the side face 32 of the burnisher 30 will polish the substantially horizontal surface 43 when the burnisher 30 is moved in the direction D of said substantially vertical surface formed by the rod 41 'forming a perfectly flat and horizontal surface 45 as visible at fig. 6.

It is therefore understood that after a finishing step comprising, for example, a deburring step, the shaft obtained 47 offers a surface 45 of perfectly flat welding ensuring welding with another piece as taught in the document PCT / EP 2015/061 774.

It is therefore understood that, in a final welding step, the ferrule 17 is adjusted to the diameter 42, that is to say that the inner face 20 of the ferrule 17 is pressed elastically against the surface of the rod 41 'and that the lower face 18 of the ferrule 17 is pressed against the surface of the bearing surface 45, then is laser welded with a guarantee that the spiral 15 and the shaft 47 are secured.

The method according to the second embodiment of the invention comprises a first step intended to provide a bar adapted to undergo a bar turning. The example relates to an assembly between a spiral and a balance shaft, the bar may be based on metal or metal alloy.

The second step is intended to décolleter different diameters needed to form the shaft 57 balance and in particular the diameter 52 adapted to receive the shell 17 of the spiral 15. In FIG. 7, it can be seen that the diameter 52 has a substantially vertical surface 51 forming a blank of the rod and a substantially horizontal surface 53 forming a draft blank.

As shown in FIG. 7, in comparison with FIG. 5, the free cutting step is intended to voluntarily form an oblique wall 54 starting from the puncture of the cutting tool towards the substantially horizontal surface 53 which is always substantially perpendicular to the substantially vertical surface 51 but in a much smaller width that the surface 43 of FIG. 5. It is understood in the case of the shaft that the oblique wall 54 thus forms a cone.

The process continues with a third step for browning the substantially vertical surface 51 to increase its hardness and improve its surface state and thus form the rod 51. Advantageously according to the invention, during the browning step, the burnisher 30 rotatably mounted according to B is moved in the direction A in contact with its main face 31 against the substantially vertical surface 51 also rotatably mounted according to C as visible in fig. 7.

In addition, during the burnishing step, the burnisher 30 continues its movement in the direction A 'until the burnisher 30 also comes into contact with its side face 32 against the substantially horizontal surface 53. then understands that the side face 32 of the burnisher 30 will polish the substantially horizontal surface 53 when the burnisher 30 is moved in the direction D of said substantially vertical surface formed by the rod 51 forming a perfectly flat and horizontal surface 55 as visible at fig. 8.

It is therefore understood that after a finishing step comprising, for example, a deburring step, the resulting shaft 57 provides a perfectly flat welding surface 55 ensuring welding with another piece as taught in the document PCT / EP 2015/061 774. It will also be seen that, with respect to the first embodiment, the second embodiment avoids the formation of burr between the blank 43 and the final span 45 as can be seen in FIG. 6.

It is therefore understood that, in a final welding step, the ferrule 17 is adjusted to the diameter 52, that is to say that its inner face 20 is against the surface of the rod 51 and its face bottom 18 is against the surface of the bearing surface 55, then is laser welded with a guarantee that the hairspring 15 and the shaft 57 are secured as illustrated in FIG. 9. It is also noted that, with respect to the first embodiment, the second embodiment makes it possible to offer a welding surface of the span 55 reduced to a width L which incidentally is even less subject to problems of flatness.

Of course, the present invention is not limited to the example shown but is susceptible to various variations and modifications that will occur to those skilled in the art. In particular, the burnisher 30 can not be limited to that presented in the present description. Indeed, depending on the desired applications, it could be of different geometry to obtain different surfaces.

In addition, as an alternative to the oblique wall 54 of the second embodiment, the bar turning step could be intended to voluntarily form a curved wall from the puncture of the bar turning tool. It is understood, in this alternative, that the curved wall would thus form a toric surface instead of a flat surface 53 followed by a cone 54 as in the second embodiment.

Claims (7)

1. A method of manufacturing a part comprising the following steps: - bring a bar; Detaching the bar to form at least one diameter comprising a substantially vertical surface and a substantially horizontal surface; - Brown the surface substantially vertical to increase its hardness and improve its surface condition; characterized in that, during the burnishing step, the burnisher is moved along the substantially vertical surface until the burnisher also contacts the substantially horizontal surface to polish said substantially horizontal surface when the burnisher is remote from said substantially vertical surface. 2. Method according to the preceding claim, characterized in that the cutting step also forms an oblique wall between the substantially vertical surface and the substantially horizontal surface to avoid forming a burr during contact of the burnisher against said substantially horizontal surface . 3. Method according to the preceding claim 1, characterized in that the cutting step also forms a curved wall around said substantially horizontal surface to avoid forming a burr during contact of the burnisher against said substantially horizontal surface. 4. A method of manufacturing a watch component comprising the following steps: Forming a first metal-based part from the method according to one of the preceding claims and a second part; - Mount a surface of the first piece on a surface of the second piece; - Welding, by electromagnetic radiation of the laser type, the surface of the first part mounted on the surface of the second part to secure them. 5. Method according to the preceding claim, characterized in that the second part is based on silicon or ceramic based. 6. Method according to the preceding claim, characterized in that the second part further comprises at least a partial coating of metal, silicon oxide, silicon nitride, silicon carbide or a carbon allotrope. 7. Method according to one of claims 4 to 6, characterized in that the first piece comprises an iron alloy, a copper alloy, nickel or one of its alloys, titanium or an alloy thereof, the gold or one of its alloys, silver or one of its alloys, platinum or one of its alloys, ruthenium or one of its alloys, rhodium or one of its alloys or palladium or one of its alloys.