EP3032347B1 - Mechanical winding device for a watch - Google Patents

Description

The invention relates to a device for automatic winding of a motor means of a watch movement.

Watch movements require motor means to provide energy to a set of mechanisms for providing at least one time indication.

For electronic watches, these means comprise a battery which supplies either electro-optical display means or one or more electric motors for driving analog display members.

For mechanical watches, it is a mainspring or barrel spring that arrests under the action of a winder operated manually or through the movements of the carrier that are transmitted to the mainspring via a connected oscillating mass to a gear reduction gear. The invention relates to self-winding watch movements using an oscillating mass.

The oscillating mass may, depending on the mechanism with which it is associated, either arm the spring using energy that the mass produces only in one direction of rotation, or in both directions of rotation.

To benefit from the energy in the two directions of rotation of the mass, it is known from the document CH-A-694,025 to use two unidirectional bearings called "one way" associated with the ball bearing of the oscillating mass. These two bearings are mounted head to tail so as to constitute an inverter. Thus regardless of the direction of rotation of the mass, it forces the barrel spring. The energy of the mass is therefore always dissipated in the winding of the spring.

The object of the invention is in particular automatic winding mechanisms whose oscillating weight arms the spring in a single direction of rotation.

We remember that in this type of mechanism, the oscillating mass is mounted guided in rotation on an axis with an unbalance. When this oscillating mass moves in a first direction of rotation, said arming direction, it drives a gear train that arms a barrel spring. When the displacement of the mass is in the other direction said free direction, this oscillating mass no longer acts on the transmission train of the spring, it is free in rotation. In the absence of movement of the carrier, the mass returns to its equilibrium point thanks to the unbalance after several oscillations which allowed it to arm the spring each time it moved in the direction of the arming.

The oscillating mass is generally suspended above the movement by means of a ball bearing having an outer ring, a core or inner ring, between which is disposed a ball cage, a screw fixing the inner ring on the movement.

The movement of the arm of the wearer of the watch can cause a rotation in one or other of the directions of rotation of the mass. With one-way winding systems, energy is recovered in only one of the two directions of rotation of the oscillating weight.

When the oscillating weight rotates in the direction of the arming, the transmission gear train ensuring the gear meshes with the outer race ring. As the mass then drives a gear train, its speed of rotation is slowed compared to its speed when it rotates in the free direction. The rolling noise in the winding direction is therefore relatively low. On the other hand in the free direction, the mass rotates at a higher speed which produces an increased rolling noise which is not desirable especially for high-end watches.

The problem is therefore to reduce the noise when the oscillating mass moves in the opposite direction to the winding direction.

The main purpose of the invention is therefore to overcome the aforementioned drawbacks as well as others by providing an automatic winding device which makes it possible to limit the noise during rotation of the mass in the free direction while ensuring safe operation. mass even in case of shocks.

For this purpose, the subject of the invention is a device for automatic winding of a mainspring of a watch movement comprising a mass fixed on a support via at least one bearing comprising a ring which drives, in a single direction of rotation. said winding direction, a transmission train for arming the mainspring, this winding device being characterized in that, on the one hand, the bearing is of the unidirectional type and blocks the rotation of the mass in the opposite direction to the direction of arming, said locking direction and in that, on the other hand, the device comprises a means for uncoupling the mass of said bearing in at least the locking direction when the mass exerts on the bearing a torque greater than a value setpoint to allow the mass to rotate at least in the blocking direction.

Thanks to these characteristics, the mass rotates only in one direction, namely the direction of arming, so that the noise related to the rotation in the free direction became blocking direction is removed. However, if a large force is exerted by the mass in the blocking direction, for example during an impact, the rotation of the mass is made possible to avoid high stresses that can lead to damage to the bearing.

• La figure 1 est un schéma de principe d'un dispositif de remontage mécanique selon un premier mode de réalisation de l'invention ;
• La figure 2 est un schéma de principe d'un dispositif de remontage mécanique selon un deuxième mode de réalisation de l'invention ;
• Les figures 3a et 3b représentent un premier exemple d'application du principe représenté à la figure 1 respectivement en vue de face et en coupe selon la ligne A-A de la figure ;
• Les figures 4a et 4b représentent un deuxième exemple d'application du principe représenté à la figure 1 respectivement en vue de face et en coupe selon la ligne B-B de la figure ;
• Les figures 5a et B décrivent le principe représenté à la figure 2 en vue de face et en coupe selon la ligne C-C de la figure ;
• Les figures 6a et 6b décrivent le principe représenté à la figure 2 en vue de face et perspective.

Other features and advantages of the present invention will emerge more clearly on reading the following description of exemplary embodiments, said description being given in a nonlimiting manner and in relation to the attached drawings among which:

• The figure 1 is a block diagram of a mechanical winding device according to a first embodiment of the invention;
• The figure 2 is a block diagram of a mechanical winding device according to a second embodiment of the invention;
• The Figures 3a and 3b represent a first example of application of the principle represented in figure 1 respectively in front view and in section along the line AA of the figure;
• The Figures 4a and 4b represent a second example of application of the principle represented in figure 1 respectively in front view and in section along the line BB of the figure;
• The Figures 5a and B describe the principle represented in figure 2 in front view and in section along the line CC of the figure;
• The Figures 6a and 6b describe the principle represented in figure 2 in front view and perspective.

Referring to the drawing, we see a mass 1 for a device for automatic winding of a mainspring of a watch movement.

This device 2 comprises a mass 1 fixed to rotation on a support formed for example by the watch movement plate via a bearing 3. Typically the mass 1 is rotatably suspended above the back of the watch movement by means of the bearing 3. 3 comprises an outer ring 4 which causes, in a single direction of rotation, said arming direction shown by the arrow Fa to figures (1 and 2 ), a gear train or gear (not shown) for transmitting the rotational movement of the oscillating mass 1 to the barrel ratchet (not shown) and arm the barrel spring (not shown). The bearing 3 further comprises an inner core or ring 5, a plurality of balls 3a distributed in a cage 6 arranged between the outer ring 4 and the core 5.

According to a feature of this winding device on the one hand, the bearing 3 is of the unidirectional type and blocks the rotation of the mass in the opposite direction of the armature, said blocking direction Fb. On the other hand, the device comprises a means 7 for uncoupling the mass 1 of the bearing 3dans at least the blocking direction Fb when the mass 1 exerts a torque greater than a set value on the ring integral with the mass 1 to allow the mass to rotate at least in the blocking direction.

This arrangement therefore allows the mass 1 to rotate in the direction F of arming. Therefore the noise that this mass makes when it circulates in the locking direction (which before, was free in rotation) is eliminated. However this solution poses a problem because the mass is rotated by the movement of the arm of the wearer of the watch and when this movement causes the mass to move in the locking direction Fb and the energy produced by this movement is too much important, this energy must be partially dissipated at risk of damaging the bearing 3. Therefore when this energy exceeds a predetermined threshold, the mass 1 can still flow in the blocking direction Fb.

The means 7 for disconnecting the core or inner ring 5 from the outer ring via the cage 6 avoids this degradation because beyond a threshold, the energy accumulated by the mass 1 can then be dissipated by relative rotation of the core 5 by set the outer ring 4 in the mass locking direction 1.

Thus, it can be seen that the core 5 is immobilized in rotation relative to the support, the ball cage 6 is designed to leave free in rotation, relative to the core 5, the outer ring 4 when it rotates in the direction of arming Fa and block the rotation of the outer ring 4 in the opposite direction of rotation said locking direction (represented by the arrow Fb to Figures 1 and 2 ).

Blocking the rotation in the blocking direction means that the outer ring 4 engages with the core 5 via the balls 3a and as the core 5 is integral with the support, the mass 1 is thus immobilized in this direction.

Mass 1 rotates only in one direction (anti-clockwise on the drawings figure 1 and 2 ) so do not make noise in the other direction.

For the Figures 3 to 6 the winding direction is a clockwise rotation.

To obtain this lock, it is possible to use unidirectional bearings called "one way" (unidirectional rotation). The principle of such a bearing is described in the patent CH 694025 which is incorporated herein by reference.

In such a unidirectional bearing, the cage 6 is formed of a ring 8 having notches 9 at its circumference. These notches have a slightly greater depth than the balls 3a to accommodate the thickness of each ball 3a. These notches 9 each extend in the plane of the bearing by a ramp 10 which is inclined with respect to a tangent to the ring 8 and rises towards the periphery thereof so that (here clockwise) figure 1 and 2 ) the ball 3a establishes a wedging between the two rings in one of the two directions of rotation.

The means 7 of uncoupling can be mounted between the core 5 and the outer ring 4 ( figures 1 , 3 and 4 ) or between the mass 1 and the bearing 3 ( figures 2 , 5 and 6 ) that is to say the outer ring.

This means of uncoupling is intended to counter strong acceleration during a shock (for example: force developed by a tennis player who engages).

The setpoint of the torque is determined by friction forces or elastic forces.

For the invention, this unidirectional bearing 3 is modified to integrate a means 7 of uncoupling to avoid harmful effects when the mass 1 is subjected to a strong impulse (shock) tending to rotate in the direction Fb blocking.

For this purpose, the bearing comprises a means 7 for uncoupling at least indirectly the oscillating mass 1 of the core 5 in the locking direction when the mass exerts a torque greater than a set value.

The automatic winding device comprises a "two-stage" bearing formed by at least three rings A, B, C mounted concentrically with, on the one hand, between two rings (A and B for the figure 1 and B and C for the figure 2 ), a connection R for a unidirectional rotation allowing the rotation of the mass in one direction that of the arming and, secondly, between two other rings (B and C for the figure 1 and B and A for the figure 2 ) a disengageable connection W in response to a force greater than a setpoint.

This disengageable link W is therefore, in one embodiment ( Figures 3a, 3b ), consisting of rolling elements such as balls 23a, or rollers between two tracks, one of the tracks having cavities 70, the other track also having cavities 71 that can be elastically deformed to let the rolling elements out of their tracks. cavities and allow rotation in the usual blocking direction.

In the case of figure 1 , the means 7 of uncoupling only acts in the blocking direction (anti-clockwise direction). The means 7 is disposed between the cage 6 and the core 5.

On the other hand, in the case of figure 2 the uncoupling means acts in both directions of rotation. The use of the means 7 for uncoupling in the winding direction may be useful when the spring is fully armed. This device makes it possible to use a fixed flange instead of a slippery flange in self-winding movements.

Different solutions were represented.

The means 7 for uncoupling therefore comprises rolling elements such as balls establishing a mechanical connection with two rings (C and B figure 1 or A and B figure 2 ) concentric each having a means 70, 71 for retaining a fraction of the rolling element, the means 71 for retaining one of the rings inoperative beyond a resistant torque exceeding a set value. Each ball cooperates with two means 70, 71 retained, one 70 belonging to a ring (C figure 3b and 4b ) and the other 71 to another ring (B figures 3b , 4b ) so that the rotation of one bearing drives the other bearing. When the retaining means of one of the rings are, for example modified by deformation, the rolling elements no longer lead to one of the rings (the cavities 71 are deformed).

The Figures 3a and 3b show in front view and in section, a solution according to the arrangement of the figure 1 .

The device comprises between the core 5 and the unidirectional bearing 3, balls 23a able to circulate in a ball cage 23. The cage 23 is formed of a part 230 integral in rotation with the core 5 and another complementary part 231 integral with rotation of the bearing 3. The balls 23a establish a mechanical connection between the complementary parts 230 and 231 of the cage. This cage has four guide faces 230a, 230b, 231a, 231b forming a tunnel. The balls 23a are held spaced from each other in the cage by means of notches 60. One 231 b of its guide faces is laterally movable to release the balls 23a from the notches and thus to disengage the two parts 230, 231 from the cage and allow a sliding rotation of the bearing 3 relative to the core 5 in the blocking direction.

To do this, the ball cage 23, which has four guide faces 230a, 230b, 231a, 231b forming a tunnel, has one 231b of its movable faces to temporarily increase the tunnel section. The faces 230a and 230b form the cavities 70 or the retaining means 70, the faces 231a and 231b form the deformable cavities 71.

According to the solution of the Figure 3a or 3b the diverging guiding face 231b is provided by an elastic blade 25 in the coupled position on the figure 3 .

The uncoupled position is not shown but in the drawing of the sectional view, it is sufficient to move the left end of the spring 25 upwards so that the ball can roll.

According to figure 4a or 4b , the solution is different from that of figure 3 in that the diverging guiding face 231b is formed by a solid part 26 held in position by an elastic blade 27 called a foil spring.

As can be understood, when the torque between the part 230 and the part 231 of the cage is greater than that fixed by the elastic effect of the blades 25 or 27, the resultant of the force between the core 5 and the bearing 3 forces the balls 23a to pass over a notch by laterally spacing the one 231 b of the guide faces which allows a sliding in relative rotation of the parts 230 and 231 of the cage. The notching of the guide faces determines singular positions.

The forces tend to spread laterally the moving face 231 b.

The figure 5a or 5b shows a technical solution according to the figure 2 .

The means 7 for uncoupling comprises a set of balls 31 housed in a ball separator 31 located between the unidirectional bearing 3 and the mass. The balls 31 are biased by a spring 33 developing a radial thrust which holds them in radial cavities 32 arranged in an inner cylindrical surface 1 a of the mass 1 or in an inner cylindrical surface of a ring integral with the mass 1.

Under the effect of the forces induced (greater than a set point) by the mass 1 wanting to flow in the blocking direction, the balls push on the spring 33 which allows the balls to come out of their cavities 32 and thus to the mass to rotate independently of the bearing 3.

The oscillating mass is guided in rotation by external bearings 50.

The figure 6 can be likened to that of the figure 5 , we find the inner ring or core 5, the outer ring 4 concentric to the inner ring with its cage 6 ball 3a.

The means 7 for uncoupling is a spring means 37 housed in a circular groove and wedged in rotation with the bearing 3, which spring means comprises at least one tongue 38 bearing elastically radially on at least indirectly the mass 1, the tongue carrying a surface radial friction along its length (face turned outwards).

The elastic tongue may have a shape 40 at its end which is wedged in a notch 41 which completes the friction effect. It is planned on the figure 6a two tabs 38 opposite.

In the cases of figure 5 and 6 the forces exerted to establish a disengageable connection are of the radial type whereas in the case of figures 3 and 4 they are forces orthogonal to the plane of rotation of the mass.

One thus integrated in the unidirectional bearing, a device of "clutch / disengagement" compact, all components can be likened to a unidirectional bearing with safety.

Claims (13)

1. Automatic winding device for a spring of a watch movement including a weight (1) fixed on a support via a bearing (3) comprising a ring (4) which drives, in only one direction of rotation called the winding direction, a transmission gear in order to wind the mainspring, this winding device being characterized in that, on the one hand, the bearing (3) is of the one-way type and blocks the rotation of the weight (1) in the opposite direction to the winding direction, called the blocking direction and in that, on the other hand, the device includes a means (7) for decoupling the weight (1) from said bearing (3) in at least the blocking direction when the weight exerts on the bearing a torque higher than a desired value.
2. Automatic winding device according to claim 1, characterized in that the decoupling means (7) is mounted between the core (5) and the outer ring (4), the weight being mounted integral with the outer ring.
3. Automatic winding device according to claim 1, characterized in that the decoupling means (7) is mounted between the oscillating weight (1) and the outer ring (4).
4. Automatic winding device according to claim 1, characterized in that the desired value is set by an elastic means and/or a friction means.
5. Automatic winding device according to claim 1, characterized in that the device includes a two-stage bearing formed by at least three concentrically mounted rings (A, B, C), said rings being arranged, on the one hand, so that between two rings, a connection (R) for one-way rotation only allows the weight to rotate in the winding direction and, on the other hand, so that a decoupling connection (W) in response to a force greater than a desired value is formed between two other rings.
6. Automatic winding device according to claim 2 or 3, characterized in that the decoupling means (7) includes rolling elements (23a, 31) forming a mechanical connection with two concentric rings each having a means (70) for retaining a fraction of the rolling element and the retaining means (71) of one of the rings becomes inoperative beyond a resistant torque that exceeds a desired value.
7. Automatic winding device according to claim 6, characterized in that between the core (5) and the one-way bearing (3), the device includes balls (23a) capable of moving in a ball bearing cage (23) formed of one portion (230) integral in rotation with the core (5) and another complementary portion (231) integral in rotation with the bearing (3), the balls forming a mechanical connection between the complementary portions (230, 231) of the cage, in that said cage (23) has four guide faces (230a, 230b, 231 a, 231 b) forming a tunnel in which the balls (23a) are arranged, in that one (231 b) of the guide faces of the cage is movable in order to release the balls (23a) and thereby separate the two portions of the cage and allow the bearing (3) to rotatably slide with respect to the core (5) in the blocking direction.
8. Automatic winding device according to claim 7, characterized in that the guide face (231 b) which moves apart is formed of an elastic strip (25).
9. Automatic winding device according to claim 7, characterized in that the guide face (231 b) which moves apart is formed of a solid part (26) held in position by a spring (27) known as a 'metal foil'.
10. Automatic winding device according to claim 6, characterized in that the decoupling means (7) includes a set of balls (31) housed in a ball (31) spacer (30) located between the one-way bearing (3) and the weight (1), the balls (31) being stressed by a spring (33) developing a radial thrust which holds the balls in radial cavities (32).
11. Automatic winding device according to claim 4, characterized in that the decoupling means (7) is a spring means (37) housed in a circular groove and mounted in rotation with the bearing (3), said spring means (37) includes at least one elastic tongue (38) radially abutting at least indirectly the weight, the tongue having a friction surface.
12. Automatic winding device according to claim 11, characterized in that the elastic tongue (38) includes a shape (40) at the end thereof that lodges inside a notch (41) which completes the friction effect.
13. Timepiece movement, characterized in that the movement includes an automatic winding device according to any of claims 1 to 12.

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