CH715641B1 - Clockwork resonator comprising at least one flexible guide. - Google Patents

Abstract

The invention relates to a clockwork resonator (100) comprising an inertial element (4; 5) suspended from a flexible strip (2) deformable in a plane XY parallel to a longitudinal direction and whose transverse extension along a transverse axis, in projection on this XY plane, is variable and of positive value on at least one side of the neutral fiber of said blade (2) which comprises, at a distance from its recesses (41; 51), a plurality of ribs (3) s extending substantially along an axis Z perpendicular to the plane, each comprising at least one generatrix which is farther from the neutral fiber than are the external surfaces of the sections (6) of the blade (2) located outside the ribs (3 ), and the longitudinal extension of each rib (3) of the blade (2), along the longitudinal axis, is less than one-fifth of the length of the blade (2) between its recesses (41; 51), the number is greater than or equal to the difference between on the one hand the quotient between said long eur and the height H of the blade (2), and on the other hand a unit.

Description

Field of the invention

The invention relates to a timepiece resonator comprising, between a first element and a second element of which at least one of the two constitutes a mobile inertial element within said resonator, at least one flexible guide constituting a return means elastic of said inertial element within said resonator and comprising at least one flexible blade joining a first recess of said first element to a second recess of said second element, said first recess defining with said second recess a blade direction, said first element and said second element each being more rigid than each said at least one flexible blade, said at least one flexible blade being arranged to deform essentially in an XY plane parallel to said blade direction, and comprising a first dimension L called length along a first longitudinal axis Y parallel to said blade direction, a second dimension E called thickness according to a second axis X transverse orthogonal to said first axis Y in said XY plane, and a third dimension H called height according to a third axis Z orthogonal to said XY plane, said first dimension L being greater than said third dimension H which is greater than said second dimension E, said at least one blade extending substantially in the form of a ribbon around or on either side of a geometric neutral fiber joining said first recess and said second recess, and comprising at least one middle zone extending transversely, along said second axis X, on either side of said neutral fiber and whose thickness is a nominal thickness EN.

The invention also relates to a timepiece, in particular a watch, comprising at least one such resonator.

The invention relates to the field of mechanical oscillator timepieces, and in particular the field of watches, where the flexible guides according to the invention make it possible to guarantee both isochronism and insensitivity to positions in space.

Background of the invention

[0004] Traditionally, a mechanical watch comprises an oscillator comprising a balance-spring, which is responsible for the good chronometric precision of the watch.

[0005] Schematically, the mechanical oscillator performs three elementary functions with: guide means, arranged to limit the degrees of freedom; inertial means; elastic return means.

[0006] More particularly for the sprung balance, these elementary functions are carried out by, respectively: pivots, typically in ruby bearings; the rim of the pendulum; the spiral spring.

[0007] The precision of traditional mechanical watches is limited by the differences in friction of the pivots of the balance wheel, according to the different positions that the watch can take in space.

[0008] Consequently, efforts are being made to develop oscillators without rubbing pivots.

[0009] A very promising way to overcome the friction of the pivots is that of oscillators with flexible guides, in which a flexible guide fulfills two elementary functions at the same time: on the one hand the guiding function and, on the other hand , the elastic restoring force or torque function.

[0010] In the case of the mechanical watch, preference is given to a flexible rotating guide, so that the shocks in translation do not disturb the oscillator, and care is taken to place the center of mass of the inertial element on the axis virtual defined by said flexible guidance.

[0011] Non-limiting examples of rotating flexible guides are described in the documents EP3035126, EP3206089, and EP18179623, all in the name of THE SWATCH GROUP RESEARCH & DEVELOPMENT Ltd. There is now a wide variety of rotating flexible guides, the manufacture of which has been made possible by the „LIGA“ and „DRIE“ technology.

[0012] The document WO2018/100122A1 in the name of LVMH describes a device for a timepiece comprising a base, an inertia regulator member rotatably mounted relative to the base, by means of an elastic suspension means connecting the regulatory organ at the base. The regulator member comprises a number n of rigid parts connected two by two by means of n elastic coupling links. The elastic suspension means comprises n elastic suspension links connecting each rigid part individually to the base.

[0013] The document EP3001257A1 in the name of ETA Manufacture Horlogère Suisse describes a clockwork resonator comprising a mass connected, by flexible strips, to attachment points of a fixed structure, and subjected to a torque and/or a effort, this resonator being arranged to oscillate with at least two degrees of freedom in translation, and the flexible blades being arranged to maintain oscillations of this at least one mass around a virtual pivot. These flexible blades have long arms, each with a developed length at least twice greater than the shortest distance between the mass and the attachment points.

[0014] The document CH712068A2 in the name of ETA Manufacture Horlogère Suisse describes a clock resonator mechanism with a pivoting mass, pivoting around a virtual axis, and comprising a flexible pivoting guide mechanism and a first and a second fixed supports to which is fixed, by a first elastic assembly and respectively a second elastic assembly which together define this virtual axis, a rotary support carrying this pivoting mass. This flexible pivoting guide mechanism is flat, the first elastic assembly comprises, on either side of the virtual axis, and joined by a first intermediate blade more rigid than each of them, a first external flexible blade and a first internal flexible blade together defining a first direction passing through the virtual axis, and the second assembly comprises a second flexible blade defining a second direction passing through the virtual axis.

[0015] The document EP2975470A1 in the name of NIVAROX SA describes an elastic rotation guide device for a clockwork mechanism allowing the rotation of one element relative to another around an axis of rotation defining an axial direction, comprising building blades, each comprising an assembly fixing part comprising a body and a functional part extending from the body to one end, the assembly fixing part and the functional part being separated by at least one slot into at least two elastically connected extensions which extend in a radial direction transverse to the axial direction, the device further comprising anchoring zones disposed at opposite axial ends of the flexible guide device, and configured to be fixed to said organs. The assembly fixing portion of each of the construction blades includes an assembly cavity or undercut and an assembly extension which intersect and interlock in a radial direction to be locked together. In order to guarantee the precision of the mechanical watch, we seek to define a rotating flexible guide whose return torque is proportional to the angle of elongation, so that the period does not depend on the amplitude of oscillation, and whose the parasitic displacements of the virtual center of rotation are the smallest, so that the period does not depend on the orientation of the watch. In addition, a guide is sought which allows large amplitudes without the stresses in the material producing rupture.

[0016] In practice, to properly ensure the guiding function of such a flexible guide, it is known to use at least two flexible blades combined in parallel, as for example in a pivot with blades crossed in projection. But the most basic form of rotating flexible guide is a single blade that works in pure flexion, and this remains a solution not to be overlooked.

[0017] As a first approximation, if a substantially flat blade is subjected to a moment, it deforms along an arc of a circle, and its end defines an angle proportional to the moment applied.

[0018] In reality, the bent blade has a slight anticlastic curvature. The anticlastic curvature is due to the fact that the fibers exterior to the neutral fiber of the blade in bending, must lengthen and therefore also contract in the directions orthogonal to the neutral fiber, and, conversely, the fibers interior to the fiber neutral are contracted and therefore extend orthogonally.

[0019] The magnitude of these orthogonal deformations is described by the Poisson's ratio. If the volume of the material is maintained, the Poisson's ratio is worth 0.5. For most common materials, the Poisson's ratio is closer to the value 0.3.

[0020] The magnitude of the anticlastic curvature depends on the local bending curvature, the Poisson's ratio of the material, the ratios between the three main dimensions of the blade, and the geometries of the embedments.

[0021] The dependence of the anticlastic curvature on the bending angle causes, if no precautions are taken, a non-linearity in the relationship between the bending angle and the applied moment.

[0022] This effect is very small, but for a mechanical watch oscillator, one thousandth of non-linearity results in an error of the order of 100 seconds per day of operation.

[0023] It should also be noted that it is sometimes sought to control the non-linearity rather than to cancel it, in order, for example, to compensate for an anisochronism caused by the escapement used.

Summary of the invention

The invention proposes to define a flexible guide for a mechanical oscillator, which is as little as possible subject to anticlastic curvature.

The invention proposes to provide the flexible blade with a suitable relief, in particular ribs, in order to control the anticlastic curvature, without significantly degrading the elastic performance of the flexible blade.

[0026] More particularly, several ribs are distributed along the flexible blade and extend according to the height of the latter, in order to stiffen it to limit the anticlastic curvature, without greatly limiting its expected bending qualities.

To this end, the invention relates to a timepiece resonator according to claim 1.

The invention also relates to a timepiece, in particular a watch, comprising at least one such resonator.

Brief description of the drawings

Other characteristics and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, where: Figures 1 to 3 represent, schematically, a flexible blade subject to anticlastic curvature: Figure 1 is a detail showing the reverse curvatures which oppose each other in the middle zone of the blade at an equal distance from the recesses; Figure 2 is a top view of this blade, and FIG. 3 is a perspective view of this same blade showing the parasitic curvature in the middle of the blade; FIG. 4 represents, similarly to FIG. 3, a conventional straight flexible blade between two recesses, in the unconstrained free state; Figures 5 and 6 show, similarly to Figures 3 and 2, a flexible blade according to the invention, equipped with ribs extending over its height, shown in bending; FIG. 7 is a rate diagram of a resonator with flexible guidance with one blade, with the rate in seconds per day on the ordinate, as a function of its amplitude in degrees on the abscissa, for different numbers of sections between the ribs with which it is equipped a blade similar to that of Figures 5 and 6; FIG. 8 is a rate diagram of a resonator with flexible guidance with one blade illustrating its anisochronism, between 20° and 10° of amplitude, with the ordinate of the rate in seconds per day, as a function of the number of sections of the blade of the resonator on the abscissa; FIGS. 9 and 10 show, similarly to FIGS. 6 and 5, a flexible strip whose ribs are arranged so as to constitute a corrugated strip whose neutral fiber is not included in the thickness of the strip, which strip crosses this neutral fiber only at the inflection zones of the undulation; FIGS. 11 and 12 show, similarly to FIGS. 9 and 10, a flexible strip whose ribs are arranged so as to constitute a corrugated strip whose neutral fiber is included in the thickness of the strip, which thus retains its rigidity maximum in tension; Figures 13 to 31 represent, similarly to Figure 5, different variants of execution of flexible blades according to the invention: figure 13: parallelepipedic straight ribs over the entire height of the blade, in symmetry with respect to the neutral fibre; figure 14: prismatic ribs with a diamond base, over the entire height of the blade, in symmetry with respect to the neutral fibre; figure 15: tubular ribs over the entire height of the blade, in symmetry with respect to the neutral fibre; figure 16: prismatic ribs based on an ellipse, over the entire height of the blade, in symmetry with respect to the neutral fibre; figure 17: parallelepipedic straight ribs over the entire height of the strip, alternating with respect to the neutral fiber according to a regular pitch; figure 18: prismatic ribs based on a half-ellipse, over the entire height of the blade, and on only one side of it; figure 19: prismatic ribs with a trapezium base, over the entire height of the blade, and on only one side of it; figure 20: prismatic ribs based on sinusoidal undulation, over the entire height of the slat, alternated with respect to the neutral fiber according to a regular pitch, and overhanging the neutral fiber; figure 21: prismatic ribs based on a broken zig-zag line, over the entire height of the slat, alternated with respect to the neutral fiber according to a regular pitch, and overhanging the neutral fiber; figure 22: prismatic ribs in cylindrical sectors, over the entire height of the slat, alternated with respect to the neutral fiber according to a regular pitch, and overhanging the neutral fiber; figure 23: prismatic ribs in slots, over the entire height of the blade, alternated with respect to the neutral fiber according to a regular pitch, and overhanging the neutral fiber; figure 24: prismatic ribs based on sinusoidal undulation, over the entire height of the blade, alternated with respect to the neutral fiber according to a regular pitch, and covering the neutral fiber; figure 25: prismatic ribs in cylindrical sectors, over the entire height of the slat, alternated with respect to the neutral fiber according to a regular pitch, and covering the neutral fiber; figure 26: parallelepipedic straight ribs over part of the height of the blade, in symmetry with respect to the neutral fibre; figure 27: concave blade symmetry with respect to the neutral fiber and with respect to a plane at mid-height of the blade; figure 28: parallelepipedic straight ribs over part of the height of the slat, comprising a rounded hollow at mid-height of the slat, in symmetry with respect to the neutral fibre; figure 29: parallelepipedic straight ribs over part of the height of the slat, comprising a rounded projection at mid-height of the slat, in symmetry with respect to the neutral fibre; figure 30: parallelepipedic straight ribs over part of the height of the slat, on either side of an opening halfway up the slat, in symmetry with respect to the neutral fibre; Figure 31: parallelepiped straight ribs over part of the height of the blade in the form of a ramp along the height; FIG. 32 is a block diagram representing a timepiece, in particular a watch, comprising a resonator according to the invention with at least one such flexible blade with relief against the anticlastic curvature.

Detailed Description of Preferred Embodiments

The invention proposes to provide the flexible blade with relief, and more particularly with ribs, in order to control the anticlastic curvature.

Figures 1 to 3 show a conventional flexible blade subject to anticlastic curvature.

[0032] Figure 4 defines the reference geometric elements used in the rest of the presentation, and represents a flexible blade 2 joining a first recess 41 of a first element 4 to a second recess 51 of a second element 5. The first recess 41 defines with the second recess 51 a blade direction D. The first element 4 and the second element 5 are each more rigid than each flexible blade 2. The flexible blade 2 is arranged to deform essentially in a plane XY parallel to the blade direction D, and comprising a first dimension L called length along a first longitudinal axis Y parallel to the blade direction D and defined by the first recess 41 and the second recess 51, a second dimension E called thickness according to a second transverse axis X orthogonal to the first axis Y in the XY plane, and a third dimension H called height according to a third axis Z orthogonal to the XY plane. The first dimension L is greater than the third dimension H, which is greater than the second dimension E.

The blade 2 extends substantially in the form of a ribbon along a geometric neutral fiber FN joining the first recess 41 and the second recess 51, and comprises at least one median zone 6, which extends transversely, along the second axis X, around or on either side of the neutral fiber FN, and whose thickness is a nominal thickness EN. Depending on the case, as seen in the figures, the blade 2 can extend around the neutral fiber FN, which then always remains in the material, or on either side of this neutral fiber FN. It is understood that this neutral fiber FN corresponds to a curve in the rest position of the blade 2, towards which this blade returns after an elastic deformation in bending,

In a variant, as seen in particular in Figure 5, several ribs are distributed along the blade and extend along the height of the blade, in order to stiffen the blade to limit the anticlastic curvature, without much stiffen for the intended bending.

[0035] FIG. 7 shows the operation of a resonator with flexible guidance with one blade as a function of its amplitude for different numbers of sections, the number of ribs here being equal to the number of sections minus one. It can be seen that the addition of a few ribs suffices to considerably improve the isochronism of the resonator.

[0036] Figure 8 shows the variation of operation (anisochronism) between 20° and 10° of amplitude, depending on the number of sections of the blade of the resonator.

Another variant consists in providing the flexible blade with corrugations, in order to control the anticlastic curvature, as visible in FIGS. 9 and 10. The proposed corrugated blade can, in projection in the XY plane, completely include the fiber neutral FN, so as not to lose the tensile rigidity of the blade.

Thus, the invention relates to a timepiece resonator 100 comprising, between a first element 4 and a second element 5, at least one of the two of which constitutes a mobile inertial element within the resonator 100, at least one guide hose 1 constituting an elastic return means for this inertial element within the resonator 100.

This flexible guide 1 comprises at least one flexible blade 2 as defined above.

More particularly, this at least one flexible blade 2 is symmetrical with respect to a median plane parallel to the XY plane, has a transverse extension which is variable along the second transverse axis X, in projection on the XY plane, with respect to the neutral fiber FN, and comprises, along this second transverse axis X, at least one relief. This relief is salient and distant from the neutral fiber FN by a distance greater than half the smallest thickness of the at least one flexible blade 2 considered, or half or the nominal thickness EN, to limit the curvature anticlastic of this at least one flexible blade 2.

More particularly, this at least one blade 2 comprises, at a distance from the first recess 41 and the second recess 51, at least one rib 3 extending substantially along the third axis Z. Each rib 3 comprises at least one generatrix 31 which is farther from the neutral fiber FN than are the lateral surfaces of the median zones 6 of the blade 2 situated outside this or these ribs 3. And the longitudinal extension LN, along the first longitudinal axis Y, of each rib 3 of blade 2 is less than or equal to one-fifth of the length L of blade 2 between its recesses.

[0042] More particularly, each rib 3 is distant, along the first axis Y, from any neck that the blade 2 has, by a value greater than or equal to the height H of the blade 2. The variant embodiments illustrated are blades without a neck.

[0043] More specifically, this at least one blade 2 comprises a plurality of median zones 6, which are sections extending along the neutral fiber FN and in the geometric extension of each other along the neutral fiber FN with the same EN nominal thickness. Each section 6 forms a ribbon, the side surfaces 60 of which are parallel to the third axis Z. And, in projection on the XY plane, at least two sections 6 are separated by a rib 3 of projecting thickness ES with respect to a side surface 60 This protruding thickness ES is preferably greater than or equal to the nominal thickness EN along the second transverse axis X. More particularly, the protruding thickness ES is at least one and a half times greater than the nominal thickness EN.

More particularly, this at least one blade 2 comprises, at a distance from the first recess 41 and the second recess 51, at least two ribs 3.

In a particular variant, blade 2 is straight, and has its neutral fiber FN straight in blade direction D.

[0046] More particularly, the sections 6 are short sections, the length of which in the first longitudinal direction Y is less than the height of the blade 2.

More particularly, the number of sections is greater than or equal to the first integer greater than or equal to the quotient L/H of the total length L of the blade 2 by its height H.

In an alternative embodiment, the blade 2 comprises alternating sections 6 following the neutral fiber FN, and ribs 3.

In another alternative embodiment, the middle zones 6 are limited to zones of inflection between rounded or pointed ribs, or the like, forming a wavy or zig-zag blade.

In a particular embodiment, this at least one flexible blade 2 comprises at least one rib 3 which extends over the entire height H of the blade 2 along the third axis Z. More particularly, each rib 3 of this blade 2 extends over the entire height H of the blade 2 along the third axis Z.

More particularly, the height H of the blade 2 is less than or equal to one fifth of the length L of the blade 2 between its recesses.

More particularly, the maximum thickness EM of the strip 2 along the second transverse axis X is less than or equal to one fifth of the height H of the strip 2.

In an advantageous embodiment in terms of manufacture, the blade 2 forms a right prism extending along the third axis Z, that is to say a solid extruded along the Z direction from a base in the XY plane, and more particularly limited by two planes parallel to the XY plane and spaced apart by the height H. More particularly the base of this prism in the XY plane is symmetrical with respect to the projection of the neutral fiber FN in this XY plane. In other words, the blade 2 can be easily produced by an extrusion-type process, or by a "LIGA" or "DRIE" process, since its geometry can be entirely described by its projection in the XY plane, raised in the third direction Z.

[0054] In certain illustrated variants, the blade may comprise a central opening, in particular when it is made on the basis of two head-to-tail wafers, or comprise a relief, or comprise two reliefs in symmetry with respect to a median plane parallel to the plane XY.

More particularly, the longitudinal extension LN of each rib 3 of the blade 2, along the first longitudinal axis Y, is less than or equal to the projecting thickness ES of the rib 3 along the second transverse axis X.

In a particular embodiment, at least one rib 3 is a rectangular parallelepiped or is part of a rectangular parallelepiped.

More particularly, these rectangular parallelepipeds extend over the entire height of the blade, and their dimension along the second transverse axis X is greater than their dimension along the first longitudinal axis Y.

In another variant, these ribs are prismatic with a diamond base, over the entire height of the blade, in symmetry with respect to the neutral fiber through which a diagonal of the diamond passes.

In a particular embodiment, at least one rib 3 is a cylinder.

In a particular embodiment, at least one said rib 3 is a tube of circular or elliptical section.

In a particular embodiment, at least one rib 3 is symmetrical with respect to the neutral fiber FN.

In a particular embodiment, at least one rib 3 is asymmetrical with respect to the neutral fiber FN.

In a particular embodiment, the blade 2 comprises, at a distance from the first recess 41 and the second recess 51, a plurality of ribs 3 protruding alternately on either side of the middle zones 6.

In a particular embodiment, at least one rib 3 is hollow or open.

In a particular embodiment, any projection of the blade 2 on the XY plane includes the neutral fiber FN.

In a particular embodiment, the blade 2 comprises, at a distance from the first recess 41 and the second recess 51, a plurality of ribs 3 regularly distributed along the first longitudinal direction Y.

According to the invention, the blade 2 comprises, at a distance from the first recess 41 and the second recess 51, a plurality of ribs 3, the number of which is greater than or equal to the difference between on the one hand the quotient L / H between the length L and the height H, and on the other hand a unit.

In a particular embodiment, the projection of the blade 2 on the XY plane comprises, at all the surface junctions, rounded fillets with a minimum radius value of 10 micrometers.

In a particular embodiment, the blade 2 is made of micro-machinable material or of silicon thermally compensated by a peripheral layer of silicon dioxide.

[0070] More particularly, the blade 2 comprises, along its length L, at least two increases in its section inertia. In a particular embodiment, the blade has at least three increases in its section inertia. These increases in its section inertia are achieved by these ribs 3 which extend in the third direction Z.

In a variant of the “corrugated sheet” type, these increases in section inertia are produced by undulations which extend on either side of the neutral fibre.

[0072] In a variant of the “inextensible sheet” type, the increases in section inertia are produced by such undulations which, seen in projection on the XY plane, include the neutral fiber.

The flexible guide 1 itself is not detailed here. More particularly, it comprises at least two such flexible blades 2. More particularly, this flexible guide is a pivot with crossed blades, with at least two blades each extending parallel to the XY plane, distinct, and crossed in projection on this XY plane .

More particularly, the blade 2 is produced by the "DRIE" or "LIGA" or similar process.

The invention also relates to a timepiece 1000 comprising at least one such timepiece resonator 100. More particularly, this timepiece 1000 is a watch, in particular a mechanical watch.

Claims (21)

1. Clockwork resonator (100) comprising, between a first element (4) and a second element (5) of which at least one of the two constitutes a mobile inertial element within said resonator (100), at least one guide flexible (1) constituting a means of elastic return of said inertial element within said resonator (100) and comprising at least one flexible blade (2) joining a first recess (41) of said first element (4) to a second recess (51) said second element (5), said first recess (41) defining with said second recess (51) a blade direction (D), said first element (4) and said second element (5) each being more rigid than each said at least one flexible blade (2), said at least one flexible blade (2) being arranged to deform essentially in an XY plane parallel to said blade direction (D), and comprising a first dimension L called length along a first axis Y longitudinal parallel to said direction of blade (D), a second dimension E called thickness along a second transverse axis X orthogonal to said first Y axis in said XY plane, and a third dimension H called height along a third Z axis orthogonal to said XY plane, said first dimension L being greater to said third dimension H which is greater than said second dimension E, said at least one blade (2) extending substantially in the form of a ribbon around or on either side of a geometric neutral fiber (FN) joining said first recess (41) and said second recess (51), and comprising at least one middle zone (6) extending transversely, along said second axis X, on either side of said neutral fiber (FN) and whose thickness is a nominal thickness EN, where said at least one flexible blade (2) is symmetrical with respect to a median plane parallel to said XY plane, has a variable transverse extension with respect to said neutral fiber (FN), along said second axis transverse X, in projection on the XY plane, and comprises, along said second transverse axis X, at least one relief which projects and is remote from said neutral fiber (FN) by a distance greater than half the smallest thickness of said at least one flexible blade (2) or of said nominal thickness (EN), to limit the anticlastic curvature of said at least one flexible blade (2), and where said blade (2) comprises, at a distance from its recesses, at least a rib (3) extending substantially along an axis Z perpendicular to the XY plane, characterized in that said blade (2) comprises, at a distance from said first recess (41) and from said second recess (51), a plurality of said ribs (3), the number of which is greater than or equal to the difference between on the one hand the quotient L/H between said length L and said height H, and on the other hand one unit. 2. Clockwork resonator (100) according to claim 1, characterized in that each said rib (3) comprises at least one generatrix (31) which is farther from said neutral fiber (FN) than are the side surfaces of said median zones (6) of said blade (2) located outside of said ribs (3), and characterized in that the longitudinal extension LN, along said first longitudinal axis Y, of each said rib (3) of said blade ( 2) is less than or equal to one fifth of said length L of said blade (2) between its recesses. 3. Clockwork resonator (100) according to claim 1 or 2, characterized in that each said rib (3) is remote, along said first axis Y, from any neck that said blade (2) has, by a value greater than or equal to said height H of said blade (2). 4. Clockwork resonator (100) according to one of claims 1 to 3, characterized in that said at least one blade (2) comprises a plurality of said middle zones (6) which are sections extending along of said neutral fiber (FN) and in the geometric extension of each other along said neutral fiber (FN) with the same said nominal thickness EN, each said section (6) forming a strip whose lateral surfaces (60) are parallel to said third axis Z, characterized in that, in projection on said XY plane, at least two said sections (6) are separated by a said rib (3) of projecting thickness ES with respect to a said lateral surface (60) , said projecting thickness ES being greater than or equal to said nominal thickness EN along said second transverse axis X. 5. Clockwork resonator (100) according to claim 4, characterized in that said projecting thickness ES is at least one and a half times greater than said nominal thickness EN. 6. Clock resonator (100) according to one of claims 1 to 5, characterized in that said blade (2) comprises, at a distance from said first recess (41) and said second recess (51), at least two ribs (3). 7. Clockwork resonator (100) according to one of claims 1 to 6, characterized in that said blade (2) is straight and has its said neutral fiber (FN) straight in said blade direction (D). 8. Clockwork resonator (100) according to one of claims 1 to 7, characterized in that said at least one flexible strip (2) comprises at least one said rib (3) which extends over the entire said height H of said blade (2) along said third axis Z. 9. Clockwork resonator (100) according to one of claims 1 to 8, characterized in that said height H of said blade (2) is less than or equal to one fifth of said length L of said blade (2) between its recesses. 10. Clockwork resonator (100) according to one of claims 1 to 9, characterized in that the maximum thickness EM of said blade (2) along said second transverse axis X is less than or equal to one fifth of said height H of said blade (2). 11. Clockwork resonator (100) according to one of claims 1 to 10, characterized in that said blade (2) forms a right prism extending along said third axis Z. 12. Clockwork resonator (100) according to claim 11, characterized in that the base of said prism in said XY plane is symmetrical with respect to the projection of said neutral fiber in said XY plane. 13. Clockwork resonator (100) according to one of claims 1 to 12, characterized in that the longitudinal extension LN of each said rib (3) of said blade (2), along said first longitudinal axis Y, is less than or equal to the projecting thickness ES of said rib (3) along said second transverse axis X. 14. Clockwork resonator (100) according to one of claims 1 to 13, characterized in that at least one said rib (3) is a rectangular parallelepiped or is inscribed in a rectangular parallelepiped. 15. Clock resonator (100) according to one of claims 1 to 14, characterized in that at least one said rib (3) is symmetrical with respect to said neutral fiber (FN). 16. Clockwork resonator (100) according to one of claims 1 to 15, characterized in that said blade (2) comprises, at a distance from said first recess (41) and said second recess (51), a plurality of said ribs (3) projecting alternately on either side of said median zones (6) 17. Clockwork resonator (100) according to one of claims 1 to 16, characterized in that any projection of said plate (2) on said XY plane includes said neutral fiber FN. 18. Clockwork resonator (100) according to one of claims 1 to 17, characterized in that said blade (2) comprises, at a distance from said first recess (41) and said second recess (51), a plurality of said ribs (3) distributed regularly along said first longitudinal direction Y. 19. Clockwork resonator (100) according to one of claims 1 to 18, characterized in that the projection of said blade (2) on said XY plane comprises, at all surface junctions, rounded fillets with a minimum radius value of 10 micrometers. 20. Clockwork resonator (100) according to one of claims 1 to 19, characterized in that said blade (2) is made of micro-machinable material, for example silicon thermally compensated by a peripheral layer of silicon dioxide. 21. Timepiece (1000) comprising at least one timepiece resonator (100) according to one of claims 1 to 20.