CH708937B1 - Oscillating element for watch movement. - Google Patents

Abstract

The invention relates to an oscillating element (1) for a watch movement comprising: an axis (3); a component (2) mounted on a first part of said axis (3) so as to be able to rotate with said axis; an elastically deformable element (5A – 5E) mounted on a second part of the axis (3) so as to allow this axis to rotate when said elastically deformable element deforms elastically; and an elastic prestressing element configured to exert a prestressing force on the elastically deformable element so as to modify the torque necessary for the rotation of said axis.

Description

Technical area

The present invention relates to an oscillating element for mechanical watch movement.

State of the art

Mechanical watch movements include many oscillating elements, in particular elements rotated alternately in one direction and then in the other. The pendulum, hairspring, escapement anchor, winding weight, and certain complications are examples of such oscillating elements.

The power reserve of a mechanical watch depends in particular on losses due to friction in the train and in the pivots of the regulating member. It is therefore advantageous to reduce this friction in order to increase the power reserve. Friction at rapidly oscillating parts, especially in the exhaust, is particularly critical. The efficiency of a classic Swiss anchor escapement is typically around 40%; 60% of the energy transmitted by the gear train to the exhaust is therefore lost in friction.

[0004] A substantial part of this friction occurs at the bearings. Despite the use of rubies and progress in lubrication, the friction between the axis of the anchor and the bearing which maintains this axis therefore represents a critical factor in the loss of energy stored in the barrel.

Furthermore, conventional bearings require play between the pivots of the movable axis and the bearing in order to allow the axis to pivot. The precision of this clearance depends on the manufacturing tolerances and the progressive wear of the bearing. This results in poorly controlled positioning of the axis and of the component mounted on this axis. In the case of an anchor, this play relates to the relative position of the paddles and the anchor wheel, which also causes energy losses.

Known in the prior art elastically deformable mechanisms which are often used to reduce friction or improve the precision of a movement. An elastically deformable mechanism is a mechanism which, unlike mechanisms based on rigid bodies, allows movement thanks to the flexibility of at least one member. For example, an elastically deformable element allows the rotation of an axis thanks to the flexibility of at least one member. The elastically deformable elements therefore partially or entirely avoid the friction of parts in movement relative to one another, and the energy losses as well as the wear of the parts which result from this friction. They also make it possible to elegantly solve the problems caused by the play of conventional bearings.

An application of the elastically deformable elements to the watchmaking field is described in patent application EP 2 037 335 A2. This document describes in particular an escapement anchor without an axis and which can rotate thanks to the deformation of two arms whose axes cross at the virtual point of rotation of the anchor. The fixing arms and the anchor form a single relatively fragile piece. In addition, the fixing arms occupy a relatively large area in the plane of the anchor which is often particularly crowded; this place is not available for other organs.

WO 2011/120 180 A1 describes a locking device for a toothed wheel based on another elastically deformable link. Again, this device is made in one piece or in one piece with the exception of the pallets, making its design difficult. An elastically deformable link integrated into the blocker also has the drawback of not being able to be easily adapted to an existing blocker; it is necessary to completely redraw the entire blocker.

Another drawback of the solutions described in these prior art is that it is very difficult to control or modify the torque necessary for the rotation of the locking devices.

Brief summary of the invention

An object of the present invention is to provide an oscillating element for a watch movement free from the limitations of known oscillating elements, in particular an oscillating element capable of oscillating with minimum torque and as low energy losses as possible.

Another object of the present invention is to provide an oscillating element for a watch movement capable of oscillating with a torque and energy losses as constant as possible.

Another object of the present invention is to provide an oscillating element based on an elastically deformable link, but which does not have the drawbacks of elastically deformable links.

Another object of the present invention is to provide an oscillating element for a watch movement based on an elastically deformable link and whose size in the plane of the oscillating functional component is as small as possible.

According to a first aspect of the invention, these aims are achieved by means of an oscillating element for a watch movement comprising: an axe; a component mounted on a first part of this axis so as to be able to rotate with this axis; an elastically deformable element mounted on a second part of the axis so as to allow said axis to rotate when the elastically deformable element deforms elastically; the elastically deformable element comprising several flexible beams forming an intersection, said axis being mounted at the intersection between said beams; an elastic prestressing element being configured to exert a prestressing force on the elastically deformable element so as to modify the torque necessary for the rotation of said axis.

According to this aspect, this construction makes it possible to separate the two functions of the oscillating element into two components on two different planes. The first functional component is on a first plane and the second component consists of an elastically deformable element on another plane. The functional component on the foreground provides a function within the framework of the watch movement; the second elastically deformable component on the second plane does not perform any function except that of "virtual" pivot for the axis of the first component. Preferably, the first and second parts of the axis are first and second ends of the axis respectively.

The elastically deformable element therefore occupies no space in the foreground of the functional component. The two components can be produced and dimensioned independently of each other, allowing optimization without compromise of each component. The elastically deformable element can for example be used with existing functional components, without modification of these components. The two components are linked to each other by an axis.

In addition, the elastically deformable element acts on an axis (which is integral with the functional component) and not directly on the periphery of the functional component as is the case in the prior art. This is advantageous, for example for components which are fragile or which have complex shapes.

The expression “elastically deformable element” designates in this text an element which allows a movement of a part, for example a rotation of an axis, thanks to the elastic deformation, for example bending, of at least part of the element. Compared to a bearing or a bearing for example, an elastically deformable element can therefore operate without friction between the movable part (for example an axis) and the fixed part.

Advantageously, the elastically deformable element is produced so as to allow rotation of an axis with as little torque as possible. It therefore exerts no restoring force on the axis, or only a negligible restoring torque or in any case voluntarily chosen to be as low as possible, at least within the range of oscillations provided.

In an advantageous embodiment, the flexible beams form a cross intersection. This construction minimizes the bulk and facilitates synthesis and simulation. The beams can for example be straight beams.

Other types of elastically deformable elements can also be used.

One or preferably two ends of two adjacent branches of the cross can be fixed to the frame of the movement by means of mounting points provided for this purpose. The mounting points can be, for example, openings for driving out or gluing fixing pins. The end (s) of the one or two branches can thus be fixed relative to the frame, while the end of the other two branches, as well as the point of intersection, can be mobile when the branches of the elastically deformable element distort.

Preferably, the preload exerted by the elastic preload element is chosen so as to minimize the torque necessary for the rotation of the axis. The prestressing is advantageously exerted simultaneously on two adjacent branches of the cross of the elastically deformable element.

The elastic prestressing element can form a single element with the elastically deformable element, which facilitates mounting and alignment.

In the preferred case of an elastically deformable element comprising two crossed beams forming a cross intersection with four X-shaped branches, the elastic prestressing element can exert a prestressing force on the two ends of two adjacent branches of the cross.

This prestressing force can be exerted directly by the elastic prestressing element on the elastically deformable element.

This prestressing force can be exerted by the elastic prestressing element on the elastically deformable element through a support piece through two branches. This solution has the advantage of distributing the prestressing force over the two branches.

This prestressing force can be exerted by the elastic prestressing element on the elastically deformable element through a support piece through two branches and an articulated connection. This solution has the advantage of allowing a relative displacement of the elastic element of prestress compared to the elastically deformable element.

The elastic prestressing element can be shaped so as to have two strands. One end of each strand is rigidly linked to one end of a fixed branch of the cross, another portion of each strand exerts a prestressing force on the free end of another branch of the cross. Preferably, the elastic prestressing element and the elastically deformable element is at least partly in the same plane.

The elastic prestressing element being dimensioned and structured so as to exert a substantially constant prestressing force on the elastically deformable element even when the elastically deformable element is deformed. Calculations and simulations have shown that a constant prestressing force makes it possible to minimize the torque necessary for the rotation of the axis, and to avoid that this torque does not depend on the angular position.

The strands can be linked to each other so as to form a ring.

The axis can be driven out and / or glued in the component and / or in the elastically deformable element.

The component may be an escape anchor, preferably a Swiss anchor for escapement with a Swiss anchor.

Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: <tb> fig. 1 <SEP> illustrates a perspective view of an oscillating element according to a first embodiment of the invention; <tb> fig. 2 <SEP> illustrates a top view of an oscillating element according to the first embodiment of the invention; <tb> fig. 3 <SEP> illustrates a side view of an oscillating element according to the invention; <tb> fig. 4 <SEP> illustrates a perspective view of an oscillating element according to a second embodiment of the invention; <tb> fig. 5 <SEP> illustrates a perspective view of an oscillating element according to a third embodiment of the invention; <tb> fig. 6 <SEP> illustrates a top view of an oscillating element according to a fourth embodiment of the invention; <tb> fig. 7 <SEP> is an exploded view of an oscillating element according to a fifth embodiment of the invention.

Example (s) of embodiment of the invention

A particular embodiment of the invention will now be described. In this preferred example, the functional component 2 which it is desired to oscillate at one end of the axis 3 is an anchor, more particularly a Swiss anchor for escapement with a Swiss anchor. The element of the invention can, however, also be used to oscillate other components.

The anchor 2 comprises in this example two pallets 20A and 20B, a fork 21 and a dart 22. It can be made of steel or advantageously of silicon or another material allowing manufacture by one of the methods from photolithography, DRIE (abbreviation for “Deep Reactive Ion Etching”) or LIGA (abbreviation for “Lithography, Galvanoformung, Abformung”) processes. It is mounted on a first end of the axis 3 by driving, for example in the case of a metal anchor, or by gluing, for example in the case of a silicon anchor. Alternatively, axle 3 and anchor 2 can be formed in one piece. An anchor integrating the pallets and / or the dart into a monolithic unit can also be envisaged.

The axis 3 is not a conventional mobile axis which pivots in bearings. Instead the oscillating element comprises, preferably at the other end of the axis 3, an elastically deformable element. In the embodiment of FIGS. 1 to 3, the elastically deformable element is of the cross type and therefore comprises two rectilinear beams 5A, 5B which intersect at X. The axis 3 is mounted at the intersection between the two beams 5A, 5B, this intersection being coincide with the center of rotation of the elastically deformable element. Non-straight beams can be used, including curved or angled beams. The four branches of the cross are referenced by the numbers 7A to 7D.

The distal ends of two adjacent branches 7A, 7B of the cross are provided with fixing points 6A, 6B to fix them on part of the movement frame, such as the plate, a bridge, an exhaust pipe, or a tourbillon cage. In a preferred embodiment, the oscillating element is fixed by means of pins or pins or screws inserted in these two fixing points. The oscillating element can be fixed on an escapement holder which also carries the escapement wheel as well as, preferably, the pendulum axis with the pendulum and balance spring. This configuration facilitates the alignment and mounting of various components of the regulating member.

In the illustrated embodiment, a connection element 60 is integrally connected to the distal end of the two branches 7A, 7B and provided with two fixing points 6A, 6B in the form of through holes. This configuration makes it possible in particular to move the fixing bridges relative to the elastic beams 5A, 5B whose deformable length can thus be maximized.

Numerical simulations have demonstrated that the torque necessary to rotate the axis 3 can be controlled, and for example reduced or even minimized, by constantly exerting a stress force on the beams 5A, 5B. In the embodiment of FIGS. 1 to 3, the two branches 7C, 7D are free and opposite the two fixed branches 7A, 7B. In this case, a constraining force is exerted by means of an elastic element, here an annular spring defining two strands 80A, 80B. This elastic element is advantageously integral with the two beams 5A, 5B of the cross. This monolithic solution notably facilitates the mounting and alignment of the various components. It is noted that with this solution, the center of rotation is not completely fixed, but the displacement of the latter is controlled, repeatable and generally less than the traditional play of a pivot of a conventional anchor rod in a stone, which is typically between 4 µm to 14 µm.

The two strands 80A, 80B start from the connection element 60 near the fixed ends of the cross and surround the two beams 5A, 5B so as to exert a prestressing force on the distal ends of the free branches 7C, 7D . More particularly, one end 81 A, 81B of each strand is rigidly linked to one end of each fixed branch 7A, 7B of the cross. They are therefore united in a single ring.

In this example, the elastic element 80A, 80B bears directly at points 81C, 81D against the distal ends of the branches 7C, 7D.

In a preferred embodiment, the prestressing force is exerted by the elastic element 80A, 80B through a support piece 9 which distributes and equalizes the pressure against the two branches 7C, 7D. This solution makes it possible to ensure equal pressure on the two branches 7C, 7D even in the event of slight differences in length due for example to manufacturing imperfections. The support element 9 can be integral, monolithic with the two branches 7C, 7D.

An articulated connecting element 90 is advantageously pivotally connected on the one hand to the strands 80A, 80B, on the other hand to the support piece 9. This connecting element guarantees a constant distance between these two elements while by allowing a rotation relative to the blades 80A, 80B and relative to the part 9. In the example illustrated, it has a shape of bone with a head, or epiphysis, approximately hemispherical at each end of a central part. Each head collaborates with a corresponding dome in the strands 80A, 80B respectively in the support piece 9.

The prestressing force exerted by the strands 80A, 80B depends on the length of the connecting element 90 and the displacement it causes on the support piece 9 and on the ends of the branches 7C, 7D. For mass production, an oscillating element can be delivered with several connecting elements of different lengths to adjust the prestressing force. The mounting of the oscillating element may include the choice of a connecting element 90 of suitable length from among several connecting elements of different lengths. In a preferred embodiment, the ideal length of the connecting element 90 is determined by numerical simulation once and for all during the design, and applied.

The elastically deformable element is therefore constituted in this example of two parts: the cross structure 5A, 5B with the elastic element 80A, 80B as well as the elements 9 and 60; and the connecting element 90. As in the other variants described below, these two parts can be made of steel, silicon, etc.

[0047] FIG. 4 illustrates a second variant of an oscillating element 1 for a watch movement. The oscillating component 2 is an anchor, shown without its paddles but which could naturally be fitted with paddles; other components could be used with this variant as well.

In this variant, the elastically deformable element comprises three flexible beams 5C, 5D 5E in a star around the axis 3. The elastic prestressing element 8 is constituted by three strands 80C, 80D, 80E forming a triangle, for example an equilateral triangle. The ends of the three beams are linked to the respective three points of the triangle.

The prestressing is therefore exerted in the same way on all three beams 5C to 5E. The end of the three beams is not blocked. One advantage is in particular that the center of the axis 3 remains almost immobile even when the part 2 is rotated.

The oscillating element 1 is fixed to the frame of the movement by the three mounting points 6C, 6D, 6E directly on the prestressing element 80C to 80E. In this example, the mounting points are linked to the midpoints of the strands 80C to 80E. In this variant, it is a displacement applied to the strands 80C to 80E which creates the stress. There is no supporting part ("bone").

Elastically deformable elements with a number of star arms other than three can be envisaged, for example elastically deformable elements with 2, 4, 5, ... N star arms around the axis 3. The angular space between the different ras is preferably constant and equal to 360 ° / N.

FIG. 5 illustrates a third variant of an elastically deformable element intended to be integrated into an oscillating element for a watch movement. As in the first variant, the elastically deformable element comprises two beams 5A, 5B forming a cross around the axis 3. The oscillating component, for example an escape anchor or a train not shown, is intended to be mounted on axis 3 in a plane other than the elastically deformable element.

The two beams 5A, 5B in X form four branches 7A to 7D whose ends are linked in pairs by the connection elements 60 respectively 61.

An elastic prestressing element 8 in a ring has two strands 80A, 80B which join the center of the connection element 60 with the center of the connection element 61, forming a ring. This elastic element 8 exerts a prestressing force directly on the distal ends of the four branches 7A to 7D. More particularly, one end 81A, 81B of each strand is rigidly linked to one end of each fixed branch 7A, 7B of the cross. No connecting piece 9 is used between the prestressing element and the connection elements 60, 61.

The elastically deformable element is mounted on the frame of the movement thanks to two mounting points 6F, 6G directly on the constraint element 8, for example in the middle of the strands 80A respectively 80B. Like the second variant, the amplitude of the prestressing force is identical on all the beams. The center of the axis 3 therefore remains stationary even during rotation of the part 2.

FIG. 6 illustrates a fourth variant of an elastically deformable element intended to be integrated into an oscillating element for a watch movement. This variant corresponds to the third variant, except that the free ends of the four branches 7A to 7D are linked to the prestressing element 8 by means of two support pieces 9A, 9B connecting the branches two by two, and bone-shaped connecting elements 90A, 90B connecting these support pieces 9A, 9B to the strands 80A, 80B of the prestressing element. These connecting elements allow movement according to several degrees of freedom of the prestressing element 8 relative to the support parts 9A, 9B and relative to the end of the beams. In this variant, it is a displacement applied to the support pieces 9A, 9B which creates the stress.

The shape and structure of the elastic element is optimized, for example by successive approximations, so that the prestressing force remains substantially constant even when the different beams of the elastically deformable element are deformed, in any the usual deformation range. This guarantees that the restoring torque exerted on the axis 3 is independent of its angular position. In one embodiment, the thickness of the strands 80A, 80B is irregular in order to achieve this objective.

[0058] FIG. 7 illustrates a fifth variant of an elastically deformable element intended to be integrated into an oscillating element for a watch movement. This variant differs from that of FIG. 5 mainly by the shape of the elastic prestressing element; the other elements may be identical to those described in relation to FIG. 5 and will therefore not be described.

The elastic prestressing element 8 is formed of two arms 80A, 80B which do not meet directly, but connect between them pairs of points on the connection elements 60, 61. More specifically, the arm 80B connects the point 600 near one end of the connection element 60 with point 610 near the corresponding end of the other connection element 61; the arm 80A connects the point 601 near one end of the connection element 60 with the point 611 near the corresponding end of the other connection element 61

The mounting points 6H, 6I of the constraint element 8 on the frame are located on the preload element 8, as in fig. 5. However, these mounting points are not directly in the middle of the strands 80A, 80B, but are connected to these strands by elastic elements 80C and 80D respectively. In this example, each of the elastic elements 80C, 80D consists of a ring, one point of which is linked to a strand 80A, respectively 80D, and another point at 180 ° is linked to one side of a mounting point 6H, 6I opposite the strand. In this way, the mounting points 6H, 6I do not limit or almost not the freedom of the strands 80A, 80B to move, which allows the constraint element 8 as a whole to exert a greater stress on the elastically deformable element.

As illustrated in FIG. 7, the elastically deformable element can be assembled on a plate 11 made for example of LIGA and comprising studs 110 intended to receive the mounting points 6H, 6I. The plate 11 can be mounted on the frame of the movement or be part of this frame. This plate 11 makes it possible to obtain better control of the prestress applied to the elastically deformable element by better precision of the centers between the studs 110. More particularly, the studs 110 and the pad 11 preferably form a single piece, thus alignment errors during assembly can be practically. In addition, there is a greater ease of assembly of the assembly on the frame of the movement, and therefore the replacement of this assembly if necessary. Finally, this plate can be integrated into an escapement door, and it can be used to adjust the position of the anchor by moving the plate on the movement frame. This plate 11 can be used in combination with oscillating elements different from that of FIG. 7, for example with an oscillating element according to any embodiment according to one of figs. 1 to 6.

All the embodiments described above comprising an elastically deformable element in a first plane connected by an axis to a functional component in another plane. It is possible to modify these embodiments so that the elastically deformable element and the functional element are entirely or partly in the same plane.

For example, it is possible to provide an oscillating element for a watch movement comprising a functional component, an elastically deformable element in the same plane and which allows this functional component to rotate when the elastically deformable element deforms elastically, and at least one elastic prestressing element which exerts a prestressing force on the elastically deformable element so as to modify the torque necessary for the rotation of the functional component.

The elastic prestressing element can be in the same plane as the elastically deformable element, and / or in the same plane as the functional component, or in another plane.

In this case, the functional component and the elastically deformable element can be in the same plane (at least partially) without necessarily being linked together by an axis. Alternatively, the functional component and the elastically deformable element may lie in different planes linked together by an axis.

In the same way, it is also possible to produce an oscillating element for a watch movement comprising an elastically deformable element formed from several beams 5A, 5B which intersect, the point of intersection of the beams defining a center of rotation for a functional component in the same plane or in another plane than the elastically deformable element. The number of beams can be two, three, etc. The beams are advantageously arranged symmetrically around the center of rotation. An elastic prestressing element 8 can be optionally provided to exert a prestressing force on the distal ends of the beams, so as to modify the torque necessary for the rotation of the functional component.

Claims (19)

1. Oscillating element (1) for a watch movement comprising: an axis (3); a component (2) mounted on a first part of said axis (3) so as to be able to rotate with said axis; an elastically deformable element (5A – 5E) mounted on a second part of the axis (3) so as to allow this axis to rotate when said elastically deformable element deforms elastically; and wherein the elastically deformable element comprises several flexible beams (5A, 5B) forming an intersection, said axis (3) being mounted at the intersection between said beams; and in which an elastic prestressing element (8) is configured to exert a prestressing force on the elastically deformable element (5A, 5B) so as to modify the torque necessary for the rotation of said axis (3). 2. Element according to claim 1, wherein the elastically deformable element comprises two flexible beams (5A, 5B) forming a cross intersection, said axis (3) being mounted at the intersection between said beams. 3. Element according to claim 2, the elastically deformable element (5A, 5B) comprising at least one mounting point (6A, 6B) rigidly connected to the ends of two branches (7A, 7B) adjacent to said cross and intended to mount said element oscillating on a frame of the watch movement. 4. Element according to one of claims 2 to 3, comprising a connection element (60) pressing simultaneously against two branches (7A, 7B) adjacent to said cross. 5. Element according to claim 4, said connection element (60) comprising at least one mounting point (6A, 6B) for mounting on a frame of the watch movement. 6. Element according to one of claims 1 to 5, said elastic prestressing element (8) and the elastically deformable element (5A – 5E) forming a single element. 7. Element according to one of claims 1 to 6, the elastically deformable element (5A – 5E) comprising at least one mounting point (6C – 6D; 6F – 6G, 6H – 6I) linked to said elastic prestressing element ( 8) and intended to mount said oscillating element on a frame of the watch movement. 8. Element according to claim 7, said at least one mounting point (6H – 6I) of the elastically deformable element (5A – 5E) being connected via an elastic connection (80C, 80D) to said elastic prestressing element (8) . 9. Element according to one of claims 4 to 8, the elastically deformable element comprising two beams (5A, 5B) forming a cross intersection with four branches (7A, 7B, 7C, 7D), said elastic prestressing element ( 8) exerting a prestressing force on the two ends of exactly two adjacent branches (7C, 7D) of said cross. 10. Element according to one of claims 4 to 8, the elastically deformable element comprising two beams (5A, 5B) forming a cross intersection with four branches (7A, 7B, 7C, 7D), said elastic prestressing element ( 8) exerting a prestressing force on the ends of each of these four branches. 11. Element according to claim 1, the elastically deformable element comprising three star branches (5C to 5E), said elastic prestressing element (8) exerting a prestressing force on a free end of each of these three branches. 12. Element according to one of claims 3 to 10, said elastic prestressing element (8) comprising at least two strands (80A, 80B), one end (81A, 81B) of each strand being rigidly connected to one end of one of said branches. 13. Element according to claim 12, said strands (80A, 80B) being pressed against the free ends of two branches (7C, 7D) of said cross by means of a support piece (9). 14. Element according to claim 12, said support piece (9) being connected to said strands (80A, 80B) by means of an articulated connection (90). 15. Element according to one of claims 12 to 14, said strands (80A, 80B) being linked to each other so as to form a ring. 16. Element according to one of claims 12 to 15, comprising a first connection element (60) bearing simultaneously against two first branches (7A, 7B) adjacent to said cross, a second bearing element (61) bearing simultaneous against two second second branches (7C, 7D) adjacent to said cross, each of said strands (80A, 80B) connecting the first support element (60) with the second connection element (61). 17. Element according to one of claims 1 to 16, said elastic prestressing element (8) being dimensioned and structured so as to exert a substantially constant prestressing force on the elastically deformable element (5A – 5E) even when the elastically deformable element deforms. 18. Element according to one of the preceding claims, the axis (3) being driven or glued in the component and / or in the elastically deformable element. 19. Element according to one of the preceding claims, said component being an anchor.