EP2908190B1 - Combined resonator with minimal friction - Google Patents

Description

Field of the invention

The invention relates to a clockwork mechanism comprising a mobile for applying a torque to a combined resonator comprising said mechanism, said combined resonator being at least two degrees of freedom and comprising a first linear resonator in a first direction and having a first mass relative to which oscillates a second linear resonator in a second direction substantially orthogonal to said first direction, said second resonator having a second mass carrying a pin having a shaft, and arranged to cooperate in the form of a system crank-rod with a groove that includes said mobile.

The invention also relates to a movement equipped with such a clock mechanism.

The invention also relates to a watch equipped with such a movement.

The invention relates to the field of watch mechanisms, and more specifically, mechanical resonators.

Background of the invention

A combined resonator is known comprising two flexible guide resonators placed in series with each other, and a mass of which carries a pin which cooperates with a groove of a mobile subjected to a torque.

However, there remains friction at this pin-groove connection, which are not constant or controlled.

The document CH703745 A2 in the name of SWATCH GROUP RESEARCH & DEVELOPMENT Ltd describes a method of producing a contactless transmission in a clockwork movement, in which a pair of antagonistic components of said watch movement, one of which causes the other, is made or relies on the other, by the application of a surface treatment giving them an electrostatic charge and / or magnetic of the same polarization and / or magnetization at the level of antagonistic surfaces, so that these antagonistic components tend to push back when they are close to each other. This surface treatment consists of depositing at least one thin layer on the contact surface and / or on the antagonistic contact surface.

The document JP2002 307254A in the name of OKAMOTO describes a magnetic linear guiding device, especially for machine tools, consisting of a guide rail having a rolling groove of a rolling element, and a freely mounted slide for relative movement in the direction axial. Permanent magnets are installed on the surface of the guide rail and the lower surface of the slider, in an arrangement such that the mating surfaces of the magnets having the same polarity (NN or SS), the load applied to the guide rail is reduced by the repulsive forces of the two magnets, and thus the service life of the linear guide device is prolonged.

Summary of the invention

The invention proposes to eliminate the friction between the pin and the groove.

For this purpose, the invention relates to a clockwork mechanism comprising a mobile application of a torque to a combined resonator that comprises said mechanism, according to claim 1.

The invention also relates to a movement equipped with such a clock mechanism.

The invention also relates to a watch equipped with such a movement.

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en plan, un résonateur combiné comportant deux résonateurs à guidage flexible mis en série l'un avec l'autre, et dont une masse de l'un porte une goupille qui coopère avec une rainure d'un mobile soumis à un couple, tel qu'une roue d'échappement ;
• la figure 2 représente, de façon schématisée et en plan, un agencement particulier de cette goupille et de la rainure de ce mobile, selon l'invention ;
• la figure 3 est un schéma-blocs représentant une montre comportant un tel mouvement équipé d'un tel résonateur combiné.

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, in which:

• the figure 1 schematically and in plan view, a combined resonator comprising two flexible guide resonators placed in series with each other, and a mass of one carries a pin which cooperates with a groove of a mobile subject a torque, such as an escape wheel;
• the figure 2 represents, schematically and in plan, a particular arrangement of this pin and the groove of this mobile, according to the invention;
• the figure 3 is a block diagram showing a watch including such a movement equipped with such a combined resonator.

Detailed description of the preferred embodiments

We know, as visible on the figure 1 a resonator combined with at least two degrees of freedom from the series connection of two flexible guide resonators O1 and O2, each having a mass M1, M2, the one M1 of the first resonator O1 being suspended by first flexible blades L1 to a fixed structure P such as a plate. The first resonator O1 oscillates essentially in a first linear direction Y. The first mobile mass M1 of this first resonator O1 serves as anchoring to the second flexible blades L2 of a second resonator O2, which oscillates essentially in a second linear direction X, substantially perpendicular to the first linear direction Y. The second mobile mass M2 of the second resonator O2 comprises a pin 2, which cooperates with a groove 1 which carries a mobile 3 subjected to a torque, typically an escape wheel.

The restoring forces are not exactly proportional to the displacements, because the flexible guides L1, L2, used in such a combined resonator are very short, which causes a non-linearity of the force of the spring as a function of the displacement, which introduces a defect of isochronism.

In addition, if the two resonators O1 and O2 are not well synchronized, it follows an elliptical movement of the pin 2 driven by the groove 1 which rotates with the mobile 3.

The nature of the guide between the pin 2 and the groove 1 therefore directly influences the isochronism.

It is possible to improve the efficiency of such a concept by eliminating the friction between the pin 2 and the groove 1 by using repulsive surfaces, especially magnets, or electrets, in repulsion. Such an arrangement is proposed on the figure 2 , in the particular non-limiting case of a magnetic repulsion.

In order to make the isochronous system, the groove 1 which serves as a guide for the pin 2 fixed on the second mass M2 of the second resonator 02 is arranged in a particular way.

Pin 2 is a radially magnetized ring 21, or in a particular embodiment illustrated in FIG. figure 2 is a shaft 20 which carries such a magnetic ring 21. In the magnetic alternative illustrated on the figure 2 the groove 1 is also magnetized so as to always be in repulsion with the ring 21.

The groove 1 may either be magnetized over its entire structure, or have sufficient individual magnets, and whose magnetization is oriented in a direction perpendicular to the local tangent to the inner surface of said groove 1. In the same way, the ring 21 may either be magnetized over its entire structure or have individual magnets in sufficient number and magnetized in a similar manner.

The groove 1 and the ring 2 thus form a crank without friction, the major advantages of which are the increase in yield as well as the reduction in wear. The auto-start of the oscillation of the combined resonator is also improved.

In an electrostatic variant, the magnets can be replaced by electrets.

In one or the other magnetic or electrostatic variant, the magnetized zone, respectively electrified, of the groove 1 and / or of the ring 21 may result from a treatment of a surface layer of the material, respectively ferromagnetic or electrostatically conductor constituting this groove 1 and / or this ring 21.

Thus, the invention relates to a mobile 3 for applying a torque to a combined resonator 10 comprising a first linear resonator 10 in a first direction Y with respect to which a second linear resonator 20 oscillates along a second direction X substantially orthogonal to this direction. Y, this second resonator 20 comprising a second mass M2 carrying a pin 2. The mobile 3 comprises a ring 21, arranged to form such a pin 2, or to be mounted on a shaft 20 that includes the pin 2. This ring 21 is slidably movable in the groove 1 of the mobile 3, and away from the side surfaces 11, 12, interior of this groove 1, under the effect of magnetic or / and electrostatic repulsion fields.

The periphery 22 of the ring 21 is thus always at a distance from these lateral surfaces 11, 12, which, in a preferred application, are parallel.

More particularly, the groove 1 is substantially radial with respect to the pivot axis D of the mobile 3.

More particularly, the groove 1 comprises at least one concave zone with respect to a radial stem from the pivot axis D.

The invention also relates to such a combined resonator 10 equipped with such a mobile 3 with a groove 1 as described above, where the pin 2 is arranged to cooperate with such a mobile 3, and constitutes said ring 21, or comprises a shaft 20 carrying this ring 21.

The invention also relates to a movement 100 equipped with such a combined resonator 10, and a watch 200 equipped with such a movement 100.

Claims (14)

1. Clockwork mechanism comprising a mobile station (3) for the application of a torque to a combined resonator that comprises said mechanism, said combined resonator with at least two degrees of freedom (10) and comprising a first linear resonator (O1) according to a first direction (Y) and comprising a first mass (M1) with respect to which a second linear resonator (O2) oscillates according to a second direction (X) that is substantially orthogonal to said first direction (Y), said second resonator (02) comprising a second mass (M2) that carries a pin (2) comprising a shaft (20), and arranged to cooperate in the form of a rod-and-handle system with a groove (1) that comprises said mobile station (3), characterised in that said shaft (20) carries a ring (21) slidably movable with minimum clearance in said groove (1) of said mobile station (3), and at a distance from lateral surfaces (11; 12) which comprises interiorly said groove (1) under the effect of magnetic or/and electrostatic repulsion fields.
2. Clockwork mechanism according to claim 1, characterised in that said ring (21) is magnetised radially.
3. Clockwork mechanism according to claim 2, characterised in that said ring (21) is magnetised over its entire structure.
4. Clockwork mechanism according to claim 2, characterised in that said ring (21) comprises individual radially magnetised magnets.
5. Clockwork mechanism according to one of claims 1 to 4, characterised in that said groove (1) is magnetised in such a way as to always be in repulsion with said ring (21).
6. Clockwork mechanism according to claim 5, characterised in that said groove (1) is magnetised over its entire structure.
7. Clockwork mechanism according to claim 5, characterised in that said groove (1) comprises individual magnets, of which the magnetisation is oriented according to a direction perpendicular to the tangent local to the inner surface of said groove (1).
8. Clockwork mechanism according to one of claims 1 to 7, characterised in that said lateral surfaces (11; 12) are parallel.
9. Clockwork mechanism according to one of claims 1 to 8, characterised in that said groove (1) is substantially radial in relation to the pivot axis (D) of said mobile station (3).
10. Clockwork mechanism according to one of claims 1 to 8, characterised in that said groove (1) comprises at least one concave zone with respect to a radial coming from the pivot axis (D) of said mobile station (3).
11. Clockwork mechanism according to one of claims 1 to 10, characterised in that said first mass (M1) of said first resonator (O1) is suspended by first flexible blades (L1) from a fixed structure (P), said first mobile mass (M1) used as an anchoring to second flexible blades (L2) that comprise said second resonator (O2).
12. Clockwork mechanism according to one of claims 1 to 11, characterised in that said mobile station (3) is an escapement wheel.
13. Clockwork movement (100) provided with a clockwork mechanism according to one of claims 1 to 12.
14. Watch (200) provided with a clockwork movement (100) according to claim 13.

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