EP4016198A1 - Method of assembling a first and at least one second mechanical or micromechanical parts in a mechanism and one-piece component for implementing the method - Google Patents

Abstract

The subject of the present invention is a method for assembling a first and at least a second mechanical or micromechanical part in a mechanism, said first and second parts being intended to be assembled in said mechanism in a determined relative position the relative to each other before cooperating with each other during the operation of the mechanism. The present invention also relates to a one-piece component for implementing the method.

Description

The subject of the present invention is a method for assembling a first and at least a second mechanical or micromechanical part in a mechanism, said first and second parts being intended to be assembled in said mechanism in a determined relative position the relative to each other before cooperating with each other during the operation of the mechanism. The mechanism is in particular a clockwork mechanism. The present invention also relates to a one-piece component for implementing the method.

A mechanism is an assembly of mechanical parts, some of which can move relative to others. When two parts cooperate or move relative to each other, it is often essential for the proper functioning of the mechanism that said parts are assembled so as to occupy a very precise determined relative position. This is particularly the case in watchmaking where the adjustment of the parts two by two, such as the lever pallet and the escape wheel, is essential. This adjustment is often time consuming and may require some skill. It may happen that the final position of a piece depends on several other pieces and that by adjusting one of its relative positions, another relative position with respect to another piece is impaired. It is then necessary to find the right balance to get as close as possible to the optimal position, the one in which the mechanism will be the most effective. It is also possible that once mounted in the mechanism, a fine adjustment of the relative position of two parts is not allowed, which requires great expertise in assembly to avoid multiple assembly / disassembly of the parts.

The object of the present invention is to provide a method for assembling a first and at least a second mechanical part or micromechanics in a mechanism, the method making it possible to guarantee the precise, quick and easy assembly of the two parts in a predetermined relative position before the mechanism is started.

The subject of the present invention is a method according to claim 1 as well as a one-piece component according to claim 6.

The appended figure illustrates schematically and by way of example a one-piece component/sample obtained after the first step of the method according to the invention.

In the following, the term “mechanical part” or “mechanical component” also covers the particular case of a micromechanical part, which is a mechanical part of very small size.

The present invention has been developed in the context of the use of a tribometer to measure the coefficient of friction between two contact surfaces of a first and a second micromechanical part intended to equip a watch movement.

Even if tribometers can be extremely specific and arranged to faithfully reproduce the movements and forces of very specific cases, they generally all have a first support intended to receive a first part of the mechanical system to be tested and a second support intended to receive a second part of the mechanical system to be tested. The tribometer is also arranged to move the supports relative to each other so as to reproduce the movement that it is desired to study between the first and second mechanical or micromechanical parts.

As explained above, the difficulty lies in the fact that one must adjust the position of the first part on the first support and the position of the second part on the second support of the tribometer while keeping a determined relative position between the first and second mechanical parts.

In the example shown in figure 1 , the first mechanical part 1 comprises a first working surface having the shape of a tip 10 while that the second mechanical part 2 comprises a second working surface having the shape of a flat face 20. The tip 10 is intended to slide with friction on the flat face 20. The use of the tribometer makes it possible to measure the coefficient of friction, wear or other tribological phenomena during the sliding of the tip 10 on the flat face 20.

The first part 1 further comprises a first alignment face 4 intended to allow the positioning of the first part 1 on the first support of the tribometer. In the same way, the second part 2 comprises a second alignment face 5 intended to allow the positioning of the second part 2 on the second support of the tribometer. The first and second mechanical parts 1 and 2 are further arranged to be able to be fixed on their respective support of the tribometer and can for this purpose comprise any suitable fixing means.

In this example, the two mechanical parts 1, 2 are preferably made of silicon, but the invention is not limited to this material.

In general, it is necessary to adjust the position of the first mechanical part 1 on the first support of the tribometer and to adjust the position of the second mechanical part 2 on the second support of the tribometer so that the mechanical parts are suitably positioned for the use of the tribometer while ensuring that the mechanical parts are also well positioned relative to each other to be able to cooperate effectively and faithfully reproduce the movement that we are trying to study. The relative position determined is the optimal position of the first mechanical part 1 with respect to the second mechanical part 2 - in the example illustrated, of the tip 10 with respect to the flat surface 20 - when they are fixed on the tribometer in its resting position.

Thus, in normal times, each time the position of one of the mechanical parts is adjusted on its respective tribometer support, there is a risk of losing their determined relative position. The precise adjustment or assembly of the mechanical parts on the tribometer can thus be long and tedious.

The method according to the invention has therefore been developed to allow easy and precise assembly of the mechanical parts on the tribometer thus guaranteeing optimal results faithfully reflecting the movements and the forces which occur between two particular mechanical parts between two micromechanical parts in a movement of watchmaking.

According to the invention, one begins by manufacturing a one-piece component formed from first and second mechanical parts integrally connected by at least one fastener in their determined relative position.

In the example illustrated, the one-piece component, called sample 100, therefore consists of the first mechanical part 1 complete with its tip 10 and its first alignment face 4, of the second mechanical part 2 complete with its flat face 20 and its second alignment face 5, the mechanical parts being integrally connected together by fasteners 3. The first mechanical part 1 and the second mechanical part 2 and in particular the tip 10 and the flat face 20 are in their determined relative position which corresponds in the position in which they should be relative to each other once the two parts have been assembled on the tribometer and before it is switched on.

• préparer une plaque de silicium ou de silicium sur isolant (SOI : Silicon On Insulator) ;
• former un masque de gravure sur la surface de la plaque, le masque détaillant donc la forme complète des première et seconde pièces mécaniques 1, 2 dans leur position relative déterminée et reliées solidairement par des attaches 3;
• graver la plaque de silicium à travers ce masque selon le procédé DRIE de manière à former l'échantillon 100 souhaité.

To produce a first mechanical part 1 and a second mechanical part 2 in silicon, the sample 100 is for example obtained according to the following steps well known to those skilled in the art:

• prepare a wafer of silicon or silicon on insulator (SOI: Silicon On Insulator);
• forming an etching mask on the surface of the plate, the mask therefore detailing the complete shape of the first and second mechanical parts 1, 2 in their determined relative position and solidly connected by fasteners 3;
• etching the silicon wafer through this mask according to the DRIE process so as to form the desired sample 100.

We therefore obtain a sample 100 as illustrated in figure 1 . This figure 1 also illustrates an example of shape and arrangement for the fasteners 3: these are strips 3a or 3b, of variable width and having at their point of direct connection with the first and second mechanical parts 1, 2, a thin part 31 intended to facilitate the detachment/removal of these bars (see third step below.)

The second step of the method according to the invention then consists in mounting or assembling the one-piece component on the tribometer at rest. To do this, the sample 100 is positioned then fixed on the first support of the tribometer thanks to the first alignment face 4 of the first mechanical part 1. The sample 100 is then positioned then fixed on the second support of the tribometer thanks to the second alignment face 5 of the second mechanical part 2. It is obvious that the order does not matter and that one could have started by fixing the sample 100 on the second support then on the first or even almost simultaneously.

This assembly step is done without changing the relative position of the tip 10 and the flat surface 20 which always remain united thanks to the fasteners 3. This step is made easier and quicker, since it is simply a matter of ensuring the correct fixing of the mechanical parts on the tribometer without worrying about having to finely adjust their relative position.

In a last step of the method according to the invention, once the sample 100 is perfectly fixed on the two supports of the tribometer, all the fasteners 3 are removed or detached in order to separate and restore their independence of movement to the first and second mechanical parts. 1, 2. Once the fasteners 3 have been removed, the first and second mechanical parts 1, 2 are therefore no longer joined together but are always in their determined relative position as long as the mechanism is at rest. It is then possible to start the tribometer to carry out the desired tests and measurements while being sure of the position of the first and second mechanical parts 1, 2 with respect to each other and in particular of the tip 10 with respect to the flat surface 20. In the example illustrated, the detachment of the fasteners 3 as close as possible to the first and second mechanical parts 1, 2, is facilitated by the presence of the thin parts 31 of the strips 3a, 3b.

The above example has been described for illustrative purposes only. The method according to the invention is not limited to a particular mechanism, nor to a size or shape of mechanical part, nor to materials, nor to particular manufacturing methods. In particular, the first manufacturing step of the one-piece component can implement any appropriate manufacturing technique including existing techniques, known and proven as very modern techniques.

Likewise, the mechanical parts can have any suitable shape. In particular, their first and second working surfaces may be contact surfaces such as the tip 10 and the flat face 20 described in the example above, but these working surfaces could equally well be arranged to be positioned one to each other without ever coming into contact. Thus, the working surfaces of the first and second mechanical parts can have a wide variety of shapes and characteristics depending on the applications and the mechanisms considered (for example in watchmaking: toothing and toothing, toothing and finger, flat and flat, etc.). .

Thus, the method according to the invention is very flexible and can be used to optimize the positioning of two parts in a wide variety of materials and is not limited by a manufacturing method.

Furthermore, the assembly method according to the invention could be applied to the assembly of a system of three or more mechanical parts.

In general, the assembly method according to the invention applies to a first mechanical part and at least one second mechanical part intended to be assembled in a mechanism to cooperate with each other when walking. of the mechanism. The mechanical parts can have any appropriate arrangement for their function, their positioning and their mounting in the mechanism (a hole allowing the driving of the part on an axis for example, a thread, an alignment face, a toothing, etc.) . The first and second mechanical parts are intended to cooperate with each other during operation of the mechanism and to do this, must be assembled in a determined relative position when the mechanism is at rest.

The mechanism is preferably a clockwork mechanism and the first and second mechanical parts are preferably micromechanical parts.

The first step of the assembly method according to the invention consists in producing a one-piece component formed from the first mechanical part and all its components and the second mechanical part and all its components, the two mechanical parts being integrally connected to each other by at least one attachment in their determined relative position. Any suitable machining or manufacturing process can be implemented to obtain the one-piece component turning, engraving, molding, laser cutting, stamping, 3D printing, galvanic growth, etc. The process according to the invention is not limited either more to a material in particular: in watchmaking, the process can be implemented for parts in silicon as in the example or even in ceramic, metal alloy, etc. Once the one-piece component has been obtained, it is possible to apply other machining or treatment steps to it (decorative treatment, surface coating, chemical functionalization, physical functionalization, etc.).

The one-piece component is preferably monolithic but could also be heterogeneous, formed from several sub-elements assembled by any appropriate means.

In a second step of the assembly method according to the invention, the one-piece component is mounted in the mechanism so that the first and second mechanical parts return to their operating position in the mechanism. This step may in particular comprise operations of gluing, screwing, driving in, snapping of the one-piece component at the appropriate location in the mechanism, in or on one or other mechanical parts. This step may also include positioning the one-piece component and one or other of the first and second parts with respect to one or more other parts of the mechanism. Since the first and second mechanical parts are held together by means of the fasteners, this assembly step makes it possible to fix the position of the first and second parts in the mechanism while ensuring that their relative position is determined.

Finally, in the last step of the assembly method according to the invention, the fastener or fasteners of the one-piece component are removed or detached to separate the first and second mechanical parts. Now independent, these two parts can therefore move relative to each other when the mechanism is started. Depending on the material chosen and the shape of the ties, these can be detached by hand, using a tool, by breaking, cutting, pinching or twisting them, or by any other suitable means.

Claims (6)

Method of assembling a first and at least a second mechanical or micromechanical part (1, 2) in a mechanism, said first and second mechanical part (1, 2) being intended to be assembled in said mechanism in a position relative determined with respect to each other before cooperating with each other during the operation of the mechanism, the method comprising the following steps: • manufacture a one-piece component (100) formed of first and second mechanical parts (1, 2) integrally connected by at least one fastener (3) in their determined relative position; • assembling the one-piece component (100) in the mechanism so that the first and second mechanical parts (1, 2) return to their operating position in the mechanism; • removing or detaching said at least one fastener (3) to separate the first and second mechanical parts (1, 2) so that the first and second mechanical parts (1, 2) are assembled in the mechanism, in their determined relative position and can cooperate with each other during the operation of the mechanism. Assembly method according to claim 1, in which the mechanism is a clockwork mechanism and the first and second mechanical parts are micromechanical parts. Assembly method according to one of the preceding claims, in which the first and second mechanical parts and therefore the one-piece component are made of silicon. Assembly method according to one of the preceding claims, in which at least one machining or treatment step is applied to the one-piece component (100) after its manufacture. Assembly method according to one of the preceding claims, in which the mechanism is a tribometer. One-piece component (100) comprising a first portion (1), at least one second portion (2) and at least one fastener (3) integrally connecting the first and second portions in a determined relative position, characterized in that the first portion (1) has the form and function of a first mechanical part intended to be assembled in a mechanism; in that the second portion has the shape and function of a second mechanical part (2) intended to be assembled in said mechanism in said determined relative position with respect to the first mechanical part and to cooperate with said first part during the running of the mechanism.

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