EP3502784A1 - Timepiece resonator with flexible guide - Google Patents

Abstract

The clock resonator (1) according to the invention comprises a base (2), a serge (3), an elastic member (4) and an ankle (6). The elastic member (4) connects the serge (3) to the base (2) and guides oscillations of the serge (3) relative to the base (2) around a virtual axis of rotation (A). The pin (6) is intended to cooperate with a fork (7a) of an exhaust (7, 8) for the maintenance of oscillations. This resonator (1) is characterized in that the pin (6) is carried by a free end (5c) of a support member (5) extending from the serge (3) towards the virtual axis of rotation ( A) and forming with the serge (3) a rigid part.

Description

The present invention relates to a flexible guide clock resonator intended to serve as a time base for a watch movement, like a sprung balance. Compared to the balance-springs, the flexible guide resonators are advantageous in that they have no axis of physical rotation and thus eliminate the friction generated by the rotation of such an axis.

Flexible guide resonators, such as that described in the patent, are known. EP 1736838 or the Zenith Defy Lab resonator, whose oscillations are maintained by a specific exhaust connected to the resonator by flexible blades.

Other flexible guide resonators have been described which are intended to be serviced by conventional escapements of the Swiss anchor escapement type. More particularly, the patent application WO 2012/010408 describes, and illustrates to figure 4 a flexible guide resonator comprising, in the same plane, a central rigid portion, an intermediate rigid portion, a rigid anchoring portion, first elastic return means forming an elastic connection between the central rigid portion and the intermediate rigid portion and second elastic return means forming an elastic connection between the intermediate rigid portion and the rigid anchoring portion. An anchor is connected to the central rigid portion to cooperate with the fork of an escapement anchor. This resonator is very specific and the use of such an anchor connected to a central rigid part does not seem applicable to other types of flexible guide resonators such as cross-blade resonators. On the other hand, the anchor is located between two blades of the first resilient return means and has little room for its oscillations, which creates the risk of collision likely to disturb the operation of the resonator.

In general, the state of the art does not propose a flexible guide resonator that can be serviced by a conventional exhaust in an optimized manner.

The present invention aims at satisfying, in part at least, this need.

To this end, there is provided a clock resonator comprising a base, a serge, an elastic member and an ankle, the elastic member connecting the serge to the base and guiding oscillations of the serge relative to the base around a virtual axis of rotation, the pin being intended to cooperate with a fork of an escapement for the maintenance of said oscillations, characterized in that the pin is carried by a free end of a support member extending from the serge to the virtual axis of rotation and forming with the serge a rigid part.

This arrangement allows a direct interaction between the exhaust and the movable rigid part of the resonator, as for the maintenance of the oscillations of a sprung balance. The support member makes it possible to place the dowel at a location close to the virtual axis of rotation which is favorable in particular for the lifting angle and / or for reducing disturbances related to vertical shocks.

According to another advantageous characteristic of the invention, the pin is located, at least in part, out of the thickness of the serge to be able to cooperate with the fork of the escapement without possible collision between the resonator and the exhaust.

The present invention further provides a clock oscillator comprising the resonator defined above and an exhaust, and a method of manufacturing the resonator.

• la figure 1 est une vue en perspective de dessous d'un résonateur horloger selon un premier mode de réalisation de l'invention ;
• la figure 2 est une vue de profil de ce résonateur ;
• la figure 3 est une vue plane de dessus de ce résonateur ;
• la figure 4 est une vue en perspective de dessous d'un oscillateur horloger comprenant le résonateur illustré aux figures 1 à 3 et un échappement ;
• la figure 5 est une vue en perspective de dessus de cet oscillateur ;
• la figure 6 est une vue de profil de cet oscillateur ;
• la figure 7 est une vue plane de dessus d'un oscillateur horloger comprenant un résonateur selon un deuxième mode de réalisation de l'invention, cette figure montrant en outre un pont d'oscillateur servant de support à l'axe de rotation d'une ancre d'échappement ;
• la figure 8 est une vue en coupe, prise suivant la ligne BB de la figure 7, de l'oscillateur illustré à la figure 7, cette figure montrant en outre le pont d'oscillateur précité et une platine sur laquelle est montée l'oscillateur.

Other features and advantages of the present invention will appear on reading the following detailed description given with reference to the accompanying drawings in which:

• the figure 1 is a perspective view from below of a clock resonator according to a first embodiment of the invention;
• the figure 2 is a profile view of this resonator;
• the figure 3 is a plan view from above of this resonator;
• the figure 4 is a perspective view from below of a clock oscillator comprising the resonator illustrated in FIGS. Figures 1 to 3 and an exhaust;
• the figure 5 is a perspective view from above of this oscillator;
• the figure 6 is a profile view of this oscillator;
• the figure 7 is a plan view from above of a clock oscillator comprising a resonator according to a second embodiment of the invention, this figure also showing an oscillator bridge serving to support the axis of rotation of an anchor exhaust;
• the figure 8 is a sectional view, taken along line BB of the figure 7 , of the oscillator illustrated in figure 7 , this figure also showing the aforementioned oscillator bridge and a stage on which the oscillator is mounted.

With reference to Figures 1 to 3 , a resonator 1 according to a first embodiment of the invention, intended to form the time base of a watch movement, in particular a wristwatch movement, comprises a base 2, a serge 3 and an elastic member 4 connecting the serge 3 to the base 2.

The base 2 may be in one part, as shown, or in two separate parts. It is intended to be fixed on a fixed or mobile support such as the movement stage or a tourbillon cage.

The serge 3 is suspended at the base 2 by the elastic member 4, that is to say is held only by the elastic member 4. It is preferably continuous, to promote its inertia compared to its mass but could be in the form of an interrupted ring. The serge 3 is coplanar with the base 2 and surrounds it, in part at least.

The elastic member 4 serves as guiding means guiding the serge 3 in rotation relative to the base 2 about a virtual axis of rotation A substantially corresponding to the geometric axis of the serge 3. The elastic member 4 also serves of elastic return means reminding serge 3 in an angular position of rest relative to the base 2.

In the example illustrated, the elastic member 4 is of the separated cross-leaf type: it comprises two elastic blades 4a, 4b crossing in plan view from above or below the resonator 1 but extending in two different parallel planes for to cross without contact. The ends of each of these blades 4a, 4b are respectively joined to the base 2 and to the serge 3. The crossing between these blades 4a, 4b defines the virtual axis of rotation A. This type of flexible guidance is advantageous in that it has a low stiffness and allows a relatively large amplitude of oscillation of the serge 3. The base 2 can be as described in the patent application WO 2017/055983 of the applicant, to allow adjustment of the position of the cross point of the blades 4a, 4b.

However, other types of flexible guiding could be used, such as crossed blades not separated (extending in the same plane and therefore physically crossing) or a pivot with a remote center of rotation called "RCC" (Remote Center Compliance ).

According to the invention, a support member 5 consisting of one or more rigid arms 5a, 5b extends, preferably in the plane of the serge 3, preferably radially, from the inner face 3a of the serge 3 towards the virtual axis of rotation A to a free end 5c. In the first embodiment, the support member 5 consists of two rigid arms 5a, 5b which meet to form the free end 5c. This free end 5c carries an ankle or ellipse 6 whose axis is parallel to the virtual axis of rotation A and perpendicular to the plane of the serge 3. In the example shown, the peg 6 has the classic shape of a half -cylinder, but it could have another form. As visible at figure 2 , the peg 6 exceeds the thickness e of the serge 3, more precisely the plane defined by the lower face 3b of the serge 3.

The part of the peg 6 situated outside the thickness e cooperates in a conventional manner with the fork 7a of an escape anchor 7, for example a Swiss anchor. the Figures 4 to 6 we can see this anchor 7 located under the resonator 1 and which interacts with the escape wheel 8a of an exhaust mobile 8 itself located under the resonator 1 and its serge 3. The exhaust 7, 8, mounted on the same support as the base 2, maintains the oscillations of the serge 3 relative to the base 2 and forms with the resonator 1 an oscillator. Being disposed in a plane parallel to that of the resonator 1, the anchor 7 and the escape wheel 8 do not interfere with the oscillations of the serge 3 regardless of the amplitude of these oscillations, which can be high. The direct interaction between the exhaust 7, 8 and the rigid moving part of the resonator 1, comprising the serge 3, the support member 5 and the pin 6, contributes to obtaining a good performance.

The radial length of the support member 5 is chosen in particular according to the desired angle of lift for the resonator 1, that is to say the angle of the serge 3 during which the pin 6 is in contact with the the fork 7a. At constant spacing between the anchor 7 and the resonator 1, arranging the pin 6 close to the virtual axis of rotation A increases the angle of lift, while moving it away from the virtual axis of rotation A decreases the angle of rotation. lifted. With a Swiss lever escapement, if one wishes to promote the yield, it is generally advantageous to have a relatively large lifting angle. If, on the other hand, it is desired to favor chronometry, a small angle of lift is generally preferable. With a flexible guide resonator such as that of the invention, the stiffness of the flexible guide and the frequency are high compared to the spiral stiffness and the frequency of a balance spring, so that the disturbances caused by the exhaust are much weaker. It will therefore be possible to give priority to the efficiency with respect to chronometry and to place the peg 6 close to the virtual axis of rotation A. It is also important that the amplitude of oscillation of the resonator is greater than the angle of lift. In exemplary embodiments of the invention, the lifting angle is two times smaller than the oscillation amplitude of the resonator 1 and the oscillation frequency is several tens of Hertz.

Preferably, as is visible on the figure 3 , in plan view from above or below the resonator 1 and when the serge 3 is in its rest position, the peg 6 is traversed symmetrically by an axis of symmetry D1 of the elastic member 4, allowing the resonator 1 to be symmetrically maintained, the elastic member 4 being biased identically during the two alternations of an oscillation. This feature improves chronometry.

Also preferably, in plan view from above or below the resonator 1 and when the serge 3 is in its rest position, the pin 6 is located on the same side of a straight line D2, perpendicular to the axis of symmetry D1 and cutting the virtual axis of rotation A, all the attachment points of the elastic member 4 to the serge 3, the base 2 being located on the other side of this line D2. In the illustrated example, said attachment points are two in number and designated 4c, 4d. In this way, the pin 6 is located in the zone of the resonator 1 which moves least in the event of a vertical impact (parallel to the virtual axis of rotation A) received by the resonator 1, and its cooperation with the fork 7a does not occur. will not be, or will be little, affected.

The resonator 1 is balanced in that the center of mass of its movable rigid part 3, 5, 6 is situated substantially on the virtual axis of rotation A. In order to compensate for the unbalance produced by the support member 5 and the ankle 6, a recess 3c (cf. figure 1 ) is formed in the lower face 3b of the serge 3, in the region of the serge 3 from which the support member 5 extends. Moreover, to facilitate this balancing of the resonator 1, the support member 5 is preferably symmetrical with respect to the axis of symmetry D1 of the elastic member 4 in plan view from above or below the resonator 1 and when the serge 3 is in its rest position (cf. figure 3 ).

the Figures 7 and 8 is represented a resonator 1 according to a second embodiment of the invention. The resonator 1 according to this second embodiment differs from that according to the first embodiment essentially by the shape of its support member 5, its base 2 and its serge 3. In particular, the support member 5 is constituted here of the two arms 5a, 5b, of different form from that of the first embodiment, and a third arm 5e which connects these two arms 5a, 5b. The symmetry characteristics described above in relation to the first embodiment are found in the second embodiment.

Advantageously, in the present invention, the axis of rotation 7b of the anchor 7 passes through the central opening defined by the serge 3, in other words is surrounded by the serge 3, as can be seen in FIG. Figures 5 to 8 . This characteristic makes the oscillator 1, 7, 8 compact in plan view from above or below while allowing the anchor 7 to have a long axis of rotation 7b, longer than that of the anchors interacting with balance-springs . A long axis of rotation improves the guidance of the anchor, making it less prone to movements out of its plane.

We can see at the figure 8 that the axis of rotation 7b of the anchor 7 has its pivots which rotate in bearings 9a, 9b respectively provided in the plate 10 of the watch movement and in an oscillator bridge 11 located above the resonator 1 and fixed by screws 11a to the plate 10. This mounting of the anchor 7 between the plate 10 and the oscillator bridge 11 avoids the use of the traditional anchor bridge interposed between the plate and the resonator. The anchor 7 and the resonator 1 can thus be close to each other in the direction of the height (direction of the virtual axis of rotation A), allowing the peg 6 to be shorter. A short peg 6 reduces the risk of tilting of the resonator 1 around the axis BB of the figure 7 during the contacts between the pin 6 and the fork 7a and the effect of a possible defect perpendicularity of the pin 6. The positioning of the pin 6 in the fork 7a and the operation of the oscillator can be particularly accurate .

The axis of rotation 7b of the anchor 7 passes through the central opening of the serge 3 between the arms 5a, 5b of the support member 5. Thus, the axis 7b can serve as a stop to these arms 5a, 5b to allow oscillations of the serge 3 only in a predetermined angular range and prevent too high amplitude oscillation of the serge 3 or that a shock leads to exceeding the yield strength of the serge 3 elastic member 4.

The anchor 7 used in the present invention can be replaced by another type of fork energy transmission member capable of communicating pulses of mechanical energy to the pin 6. The anchor 7 can for example be replaced by the trigger rocker of a percussion escapement as described in the patent application WO 2018/002778 of the plaintiff.

As shown in figure 8 , the base 2 of the resonator 1 is mounted on the plate 10 via a bridge 12. Alternatively, however, it could be mounted directly on the plate 10. The attachment of the base 2 and the bridge 12 to the plate 10 is provided by positioning pins 13 and holding screws 14.

In a variant of the invention, the bearings 9b and 9a in which the pivots of the axis of rotation 7b of the anchor 7 rotate are provided respectively in the bridges 11 and 12, allowing these bridges to anchor 7. and the resonator 1 to form together a module, the module of which the escape mobile 8 can also be part by pivoting itself also in the bridges 11, 12.

Advantageously, stops 15, 16 integral with the oscillator bridge 11 limit undesirable movements of the serge 3 during shocks. The abutment 15 is arranged to act on the serge 3 in several directions of translation of the plane of the resonator 1 and in the direction of the height. The stop 16 is arranged to act on the serge 3 in the direction of the height. In the example shown, the stops 15, 16 are driven into the oscillator bridge 11 and can therefore be adjusted in height to ensure an ideal operating clearance. The abutments 15, 16 could, however, be in one piece with the oscillator bridge 11.

Like conventional rockers, the serge 3 of the resonator 1 according to the invention can be equipped with flyweights 17 for adjusting the moment of inertia of the movable rigid part 3, 5, 6.

With the exception of any flyweights that are reported, the resonator 1 may be entirely monolithic and made for example of silicon or any other suitable material according to the technique of deep reactive ionic etching ("DRIE") (Deep Reactive Ion Etching), in nickel, nickel alloy or any other material suitable for LIGA (lithography, electroplating, molding), steel, copper-beryllium, nickel silver or other metallic alloy by milling, electroerosion or 3D printing, in metallic glass by molding, or glass, sapphire or any other suitable material according to the laser micro-structuring technique coupled with chemical etching (eg FEMTOPRINT®).

Preferably, however, in order to facilitate the manufacture and avoid the use of complicated multi-level processes, especially of more than two levels, the coplanar parts that are the base 2, the serge 3, the elastic member 4 and the organ 5 are made together so as to form a monolithic piece, for example according to one of the aforementioned techniques such as the DRIE or LIGA technique, then the peg 6, made of the same material or another material, is assembled at the same time. support member 5. To do this, the pin 6 can be introduced into a hole 5d previously formed in the end 5c of the support member 5 and be fixed there for example by gluing or brazing. In a preferred embodiment, the assembly 2, 3, 4, 5 and the pin 6 are both made of silicon.

In the case where the material chosen for the resonator 1, more particularly for the elastic member 4, has an anisotropic modulus of elasticity, for example silicon cut in a plane of the family {100} or in a plane of the family {110}, the blades 4a, 4b forming the elastic member 4 are preferably oriented each in a crystalline direction in which the modulus of elasticity is the lowest. For example, in the case of silicon {100} or {110} the blades 4a, 4b are each oriented in a crystalline direction of the family <100>. In this way, for a given stiffness of the elastic member 4, the thickness of the blades 4a, 4b may be larger, which facilitates the manufacture.

All or part of the surface of the resonator 1 may be covered with one or more layers. In particular, it is possible to provide a thermal compensation layer, typically made of silicon dioxide in the case of a silicon assembly 2, 3, 4, 5, over the entire resonator 1 or at least on the elastic member 4 in order to compensate the thermal variations of the stiffness of the elastic member 4.

Claims (20)

Clock resonator (1) comprising a base (2), a serge (3), an elastic member (4) and an ankle (6), the elastic member (4) connecting the serge (3) to the base (2) and guiding oscillations of the serge (3) with respect to the base (2) around a virtual axis of rotation (A), the pin (6) being intended to cooperate with a fork (7a) of an escapement ( 7, 8) for the maintenance of said oscillations, characterized in that the pin (6) is carried by a free end (5c) of a support member (5) extending from the serge (3) towards the virtual axis of rotation (A) and forming with the serge (3) a rigid part. Clock resonator (1) according to claim 1, characterized in that the pin (6) is located, at least in part, out of the thickness (e) of the serge (3). Clock resonator (1) according to claim 1 or 2, characterized in that the support member (5) is monolithic with the serge (3). Clock resonator (1) according to any one of claims 1 to 3, characterized in that the base (2) and the elastic member (4) are monolithic with the serge (3). Clock resonator (1) according to any one of claims 1 to 4, characterized in that the pin (6) is fixed in a hole (5d) of the support member (5). Clock resonator (1) according to any one of claims 1 to 5, characterized in that in plan view from above or below the resonator (1) and when the serge (3) is in a rest position with respect to the base (2), the peg (6) is traversed symmetrically by an axis of symmetry (D1) of the elastic member (4). Clock resonator (1) according to claim 6, characterized in that in plan view from above or below the resonator (1) and when the serge (3) is in said rest position relative to the base (2), the support member (5) is symmetrical with respect to said axis of symmetry (D1). Clock resonator (1) according to any one of claims 1 to 7, characterized in that the serge (3) comprises a recess (3c) which compensates for the unbalance provided by the support member (5) and the peg ( 6). Watchmaker resonator (1) according to one of Claims 1 to 8, characterized in that in plan view from above or below the resonator (1) and when the serge (3) is in a rest position with respect to the base (2), the peg (6) is located on the same side of a line (D2), perpendicular to an axis of symmetry (D1) of the elastic member (4) and intersecting the virtual axis of rotation ( A), that all the points (4c, 4d) of attachment of the elastic member (4) to the serge (3). Clock resonator (1) according to any one of claims 1 to 9, characterized in that the serge (3) is continuous. Clock resonator (1) according to any one of claims 1 to 10, characterized in that the elastic member (4) comprises first and second crossed elastic blades (4a, 4b) extending in different parallel planes. Clock resonator (1) according to any one of claims 1 to 11, characterized in that the elastic member (4) is made of a material having an anisotropic modulus of elasticity and comprises elastic blades (4a, 4b) s each extending in a crystallographic direction of the material in which the modulus of elasticity is the lowest. Clock oscillator comprising a resonator (1) according to any one of claims 1 to 12 and an escapement (7, 8), the escapement (7, 8) comprising a fork (7a) arranged to cooperate with the pin (6) . Clock oscillator according to claim 13, characterized in that the fork (7a) is situated in a plane different from that of the serge (3). Clock oscillator according to claim 14, characterized in that the axis of rotation (7b) of the fork (7a) is surrounded, at least in part, by the serge (3). Clock oscillator according to claim 15, characterized in that the axis of rotation (7b) of the fork (7a) is arranged to serve as a stop for the support member (5) in both directions of rotation of the serge (3) to prevent exceeding the elastic limit of the elastic member (4). Clock oscillator according to Claim 15 or 16, characterized in that the resonator (1) is located between a bridge (11) and the fork (7a) and in that that one of the two pivots of the axis of rotation (7b) of the fork (7a) is arranged to pivot in this bridge (11). Clock oscillator according to claim 17, characterized in that the bridge (11) carries at least one stop (15, 16) for limiting undesirable movements of the serge (3). Clock oscillator according to any one of claims 14 to 18, characterized in that the fork (7a) is part of an anchor (7) in said plane different from that of the serge (3). A method of manufacturing a clock resonator (1) according to any one of claims 1 to 12, comprising a first step of producing, on the one hand, a monolithic piece comprising the base (2), the serge (3) , the elastic member (4) and the support member (5) and, secondly, the dowel (6), and a second step of assembling the monolithic piece and the dowel (6).

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