CH717283B1 - Watch assembly comprising an oscillating element and an escapement. - Google Patents

Abstract

The present invention relates to a timepiece assembly comprising: an oscillating element (1) for a watch regulating member, an escapement, characterized in that said oscillating element for a watch regulating member comprises: a first zone (10) whose oscillations determine the rate of said member regulating, a second zone (20) distinct from the first zone (10), said second zone (20) being linked to the first zone and having a volume greater than the volume of the first zone, said second zone (20) has a shape arranged to compensate for the deformations of the first zone (10) caused by temperature, by temperature variations, by magnetic fields or by gravity in order to improve the isochronism of said watch regulating member, and in that a common substrate comprises said oscillating element and said exhaust, said common substrate being plate-shaped, said exhaust and said oscillating element being formed by recess in said common substrate.

Description

Technical area

The present invention relates to a watch assembly, comprising an oscillating element for a watch regulating member, for example a spiral spring whose oscillations determine the course of the movement, and an escapement.

State of the art

The regulating member of mechanical watches is usually composed of a balance, which is a flywheel, on the axis of which is fixed a spiral spring called a spiral or spiral spring. The hairspring is fixed to the balance axis by means of a ferrule, to which the hairspring can be pinned, welded, glued, etc. The other end of the hairspring is fixed to the plate or to a bridge by means of a eyebolt, in which the hairspring is pinned or glued to the cock either directly or by means of a mobile eyebolt holder.

[0003] Between the ferrule, the position of which is fixed since it is linked to the axis of the balance which can only turn on itself - and the eyebolt which is linked to the plate, the hairspring can be deformed depending on the temperature, gravity, etc. which harms isochronism. Even in the absence of disturbances, the center of mass of the hairspring moves with each oscillation relative to its center of rotation, resulting in an oscillation that is not perfectly isochronous.

Indeed we seek to obtain the most isochronous oscillations of the hairspring possible, that is to say oscillations which occur at equal time intervals, independently of their amplitude, regardless of the variations or absolute values of temperature, force of gravity, magnetic field, etc.

[0005] In the state of the art, it is known to produce the balance springs in invar, an alloy of iron and nickel which is not very sensitive to magnetism and has a very low coefficient of expansion. However, since its hardness is low and its thermal coefficient is bad, it is necessary to add various additives to the invar. In addition, since its Young's modulus, or modulus of elasticity, is not optimal for a hairspring, invar hairsprings are larger than those made from another material, for example steel.

Philips at the end of the 19th century studied the end curves of the hairspring, or Philips curves, which allow the center of gravity of the hairspring to be at the center of the hairspring, that is to say on the axis of the hairspring. balance wheel, throughout the oscillation. Depending on the application, a particular Philips curve must be chosen from among the various existing Philips curves, each curve being designated by a number. However, this solution does not make it possible to compensate for deformations of the hairspring linked, for example, to temperature variations. In addition, it only allows an average correction of the deformation of the hairspring, without giving the possibility of a correction or fine adjustment.

[0007] Document US2008117721 describes an oscillating system, the outer end of the spiral spring of which is fixed to a retaining element whose position can be adjusted in a fixed radial guide, for example using screws, in order to compensate for errors of isochronism. Adjusting the position of the retaining element, and therefore of the eyebolt, requires the user to open the watch. It is therefore carried out once and for all, and cannot be easily modified according to rapid variations in temperature or the inclination of the watch.

[0008] Document EP1422436 describes a balance spring spring cut from a monocrystalline silicon wafer, the turns of which have a width and a thickness dimensioned so as to minimize the thermal drift of the assembly. It is coated with a layer of amorphous silicon oxide. The presence of silicon and its oxide whose temperature coefficients are of opposite sign makes it possible to reduce the deformations of the hairspring caused by variations in temperature, but not other deformations, for example those caused by a variation of the inclination and of the action of gravity. Furthermore, expansion compensation is only possible within a limited temperature range.

[0009] Document EP2184652 describes a curved elevation hairspring comprising a silicon hairspring having an end curve and a lifting device between the outer coil of the hairspring and the end curve in order to improve the development concentricity of the hairspring. . The hairspring comprises at least a part of silicon oxide in order to make it more mechanically resistant and to adjust its thermoelastic coefficient. The elevation device makes the outer turn of the hairspring integral with the terminal curve. This arrangement makes it possible above all to compensate for the deformations of the hairspring caused by temperature variations, but not those due to other factors. In addition, the lifting device of this solution makes the hairspring bulky.

Document CH699494 describes a mechanical oscillator having an optimized thermo-elastic coefficient comprising a spiral spring consisting of a single-crystal silicon core and at least one peripheral coating based on a material having a different thermo-elastic coefficient that of silicon, monocrystalline silicon being oriented along the crystallographic axis {1,1,1} to optimize the thermal coefficient of the mechanical oscillator as a whole. This solution only makes it possible to compensate for deformations of the hairspring caused by temperature variations in a reduced variation range.

[0011] Document EP1612627 relates to a two-material self-compensating balance spring. The use of two materials makes the hairspring manufacturing process more complex.

Document EP1791039 describes a balance spring made from a photo-structurable glass plate and having areas subjected to UV illumination in order to be more easily and selectively removed by chemical attack. Since glass does not have good mechanical properties for a hairspring, these properties can be improved by adjusting the shape of the masks and / or their number, which however makes the manufacturing process complex and expensive.

Document EP1519250 describes a thermo-compensated balance-spring resonator by cutting and structuring according to orientations determined with respect to the crystallographic axes of a quartz crystal. The resonator must therefore be made of a crystalline material having crystallographic axes, which limits the choice of material to be used for the resonator.

In known watch assemblies, the oscillating element and the escapement are two separate components which must be assembled, which involves assembly costs and also energy losses linked to the connections between the oscillating element. and the exhaust.

[0015] There is therefore a need for a watch assembly which makes it possible to avoid at least one of the limitations of the state of the art mentioned.

Brief summary of the invention

An object of the present invention is to provide a watch assembly free from the limitations of known oscillating elements.

Another object of the invention is to provide a watch assembly comprising an oscillating element for a regulating member which makes it possible to compensate for the deformations of the element caused by temperature variations, by the variable influence of gravity according to inclination for example, or due to the oscillations of the element, in order to guarantee the isochronism of the regulating organ.

[0018] According to the invention, these aims are achieved in particular by means of a timepiece assembly according to claim 1.

This solution has the particular advantage over the prior art of providing in a common plate-shaped substrate both an oscillating element and an escapement: therefore, there is no need to assemble these two components, thereby reducing or avoiding any problem or cost associated with assembly.

In this context, the expression "oscillating element" indicates an element capable of oscillating so as to regulate the rate of the movement. The oscillating element has physical characteristics such as, for example, a mass, a coefficient of expansion, a Young's modulus or modulus of elasticity, a Poisson's ratio in order to characterize the contraction of matter perpendicular to the direction of l 'applied force, etc. It also has geometric characteristics, in particular a shape as a function f (θ, r) which represents a mathematical curve parameterized as a function of an angle θ and a radius r, f preferably belonging to to the family of cycloid curves with isochronic properties, that is to say with oscillations which occur at equal time intervals, independently of their amplitude. An oscillating element therefore produces in combination with the balance a characteristic modulation (or response) in frequency and amplitude, which can be represented with a periodic function.

In a preferred variant, the oscillating element is a spiral spring. In another variant, the oscillating element is a pendulum, for example an Foucault pendulum, or any other oscillating element, rectilinear or not, with isochronous properties.

According to the invention, the oscillating element for a horological regulating member comprises a first zone whose oscillations determine the rate of said regulating member, a second zone linked to the first zone and having a volume greater than the volume of the first zone, said second zone has a shape designed to compensate for the deformations of the first zone in order to guarantee said isochronism.

The second zone has a larger volume than the volume of the first zone: in fact a larger volume makes it possible to store more mechanical energy, which makes it possible to compensate more effectively for the deformations of the first zone.

The shape of the second zone is advantageously calculated numerically (for example using finite element calculation or numerical mathematical methods for solving an equation) under the constraint that the isochronism of the regulating organ is guaranteed.

The second zone therefore acts as a filter, for example a band-pass filter, to damp the oscillations transmitted from the first zone to the movement plate. The filtering is chosen so as to improve the isochronism of the watch.

In a variant, the first zone is in the form of a spiral spring. Other shapes of oscillating elements, for example oscillating elements in the form of a beam, an oscillating pendulum, a non-parallelepipedal element, etc., can be chosen for the first zone.

The first zone and the second zone are advantageously formed by cutting from a common substrate. The first zone and the second zone are then advantageously produced in the same material (s). The hollow substrate can be made from a single material, for example from silicon or from any material which can be deformed in space and which a person skilled in the art deems appropriate for this application. In another variant, the substrate comprises two or more layers of different materials. In another variant, the substrate is hollow.

In a preferred variant, the substrate is planar, so that the first and the second zone belong to the same plane. In another variant, the substrate is not planar and the first and the second zone belong to different planes. This last variant is more bulky than the first, but makes it possible to increase the degrees of freedom to define the shape of the second zone.

A multilayer substrate, with layers formed in several materials or in the same material but with a different crystal structure, can also be used. The use of several layers makes it possible to optimize the filtering function. For example, one of the layers can be amorphous and the other crystalline.

In another variant the recess in a common substrate is made by photo-lithographic techniques.

In a variant, the second zone comprises one or more positioning and / or fixing holes for fixing it to the plate of the timepiece to which the regulating member belongs. One or more pins and / or one or more screws cooperate with this or these holes for positioning and / or fixing.

Advantageously, in the case where the oscillating element is a spiral spring, the presence of a eyebolt to fix the hairspring to the cock and therefore to the plate is no longer necessary; the fixing to the plate is guaranteed by the hole (s) of the second zone cooperating with one or more pins and / or one or more screws. In other words, the function of the eyebolt in a variant of the invention is performed by the second zone of the oscillating element.

The second zone is arranged to compensate for the undesirable deformations of the first zone caused by external factors, such as variations in temperature, in the magnetic field, or the influence of gravity, or even the own oscillations of the oscillating element. In a variant of the invention, in fact, the calculated deformations of the second zone compensate for the undesirable deformations of the first zone. In the case where the oscillating element is a spiral spring, the second zone is also arranged to control the position of the ferrule of the spiral spring, that is to say that the deformations of the second zone due to temperature or to gravity produces a displacement of the outer point of the spiral spring which is optimized to compensate for unwanted spiral spring deformations.

In one embodiment, the first zone is an oscillating element attached to a plate via the second zone. The first zone can be a hairspring mounted on an axis and the second zone a zone which makes it possible to connect one end, for example the outer end, of this hairspring or of another oscillating element, to a fixed point of the movement.

The second zone therefore makes it possible to dynamically control and correct the oscillations of the first zone on which it acts by the connection point between these two zones, for example by the outer end of a first zone shaped as a spiral.

The second zone can have a complex shape, comprising for example many branches of varying thicknesses, connected by bifurcations, etc.

In an unclaimed variant, there is provided a method of mathematically calculating an optimum shape of a second zone of an oscillating element for a regulating member, this second zone being linked to a first oscillating zone, the oscillations of this first zone determining the isochronism of the regulating organ, this second zone having a volume greater than the volume of the first zone, the method comprising the following step: definition of said shape in order to compensate for the deformations of said element in order to guarantee said isochronism.

Advantageously, the mathematical calculation is a finite element calculation. A calculation involving the resolution of differential equations defining the topology of the oscillating element can also be employed.

The plate is advantageously modeled as a sum of simple elements (for example beams, etc.) linked together through connections, for example pivots, etc.

In a variant, the method also comprises the creation of a vocabulary of simple geometric shapes writing a grammar for this vocabulary.

One or more mathematical equations are solved with the constraint that the oscillating element is isochronous.

One or more topological gradients are also calculated to optimize the shape of the second zone.

This solution has the particular advantage over the prior art of ensuring the isochronism of the regulating member by compensating for the undesirable deformations of the first zone caused by variations in temperature, gravity or oscillations of said element with calculated strains of the second zone.

Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: FIG. 1 illustrates a representation of an example of a pivot connection of a simple geometric shape belonging to the vocabulary which may be defined in a step of the mathematical calculation method according to an unclaimed variant of the invention. FIG. 2 illustrates a representation of a possible combination of simple geometric shapes which belong to the second zone of the oscillating element of the watch assembly according to the invention, this combination being linked to the first zone. FIG. 3 illustrates a possible embodiment of the regulating member of the watch assembly according to the invention.

Example (s) of embodiment of the invention

The oscillating element for a watch regulating member of the watch assembly according to the invention comprises two zones, a first and a second zone. The first zone constitutes a mechanical oscillator whose oscillations determine the course of the movement; external disturbances, for example due to temperature or to the influence of gravity as a function of the inclination, as well as displacements of the center of gravity or of the baricenter, however disturb the isochronism of the oscillator. The second zone has a shape designed to compensate for the deformations of the first oscillating zone in order to guarantee the isochronism of the regulating member.

The shape so of the second zone can be defined during the design using a finite element calculation. The first step in defining this shape includes creating a vocabulary of simple geometric shapes, such as rectangle (beam), triangle, circle, etc., each shape being characterized by a different moment of inertia. The shapes can be defined in two dimensions in the case of a plate, or in three dimensions if variations in thickness are useful.

Advantageously, the dimensions of these basic shapes are compatible with the desired dimensional resolution of the oscillating element, for example a spiral spring.

Different elementary mechanical links are used to model the relationships between two or more basic shapes linked together by physical contacts. An example of an elementary mechanical connection is the pivot connection or the sliding pivot connection.

Each elementary mechanical link can be represented by two torsors, a kinematic torsor and a stress torsor, each torsor being composed by two lines, the first line representing a translational movement and the second a rotational movement, and by three columns, each column representing a reference respectively to the x, y or z axis of an orthogonal reference system.

FIG. 1 illustrates a representation of an example of a pivot link of a simple geometric shape Mo belonging to the defined vocabulary. The pivot connection guides the form Mo in rotation and only allows rotation about the connection axis, which in the example illustrated is the y axis.

The kinematic torsor and the stress torsor in the example of FIG. 1 have the following shape which indicates that the form Mo can only rotate around the y axis. The coefficients cy and typ can be normalized to 1.

After the creation of the vocabulary of simple geometric shapes, a grammar is defined for this vocabulary, that is to say a set of rules which manage the mechanical connections in a "sentence", that is to say a set of words composed by simple geometric shapes.

In a regulating member, a spiral spring can undergo deformations due to the force of gravity, the absolute temperature or temperature variations or its own oscillation: the spiral spring therefore deforms kinematically and its center of gravity O 'moves with respect to its internal end O.

In a variant, the shape of the second zone 20, visible in FIG. 3, is calculated by solving the following equation: f (O, O ') = const | t (2) which imposes a constant distance between the center of gravity O 'and the point of attachment to the shell in time t. Solving this equation makes it possible to define the shape of the second zone 20.

In fact, in a variant, the outer end of the oscillating element, that is to say that intended to be linked to a stud in the case of a spiral spring, is linked to the fixed plate by means of the deformable zone cut out from a substrate and which can be modeled by a sentence composed of elements or forms Mi, as illustrated in FIG. 2. The forms M1, M2 and M3 of FIG. 2 in fact form a sentence and are linked by elementary mechanical bonds. The form M1 is directly linked to the first zone 10 comprising the oscillating element, for example a spiral spring, in correspondence of the point P and the three forms belong to the same surface of the first zone 10 and constitute the second zone.

By constraining the point P, for example by forcing it to follow an ideal path, thanks to the connection with the second zone 20, the deformations of the first zone 10 are compensated for by the deformations of the second zone 20 so as to that for example temperature variations no longer affect the position O of the spiral spring. The isochronism of the regulating organ is thus guaranteed.

Equation (2) allows regulation of the deformation compensation by optimizing the surfaces of the second zone 20 by calculating topological gradients. In other words, the regulation is carried out by surface optimization.

FIG. 3 illustrates a possible embodiment of the oscillating element 1 of the watch assembly according to the invention. It comprises a first zone 10 in the form of a spiral spring, and a second zone 20 linked to the first zone and having a volume greater than the volume of the first zone 10. The shape of the second zone 20 is calculated in order to guarantee the volume. isochronism of the regulating organ.

The two zones 10, 20 are formed by recessing in a common substrate 2, for example a plate.

The second zone 20 comprises one or more positioning and / or fixing holes 30 which cooperate respectively with one or more pins and / or one or more screws to position respectively fix the part 1 to a plate.

The common substrate 2 can be made from a single material, for example from silicon or from any material which can be deformed in space and which a person skilled in the art judges suitable for this application. In another variant, the substrate comprises two or more layers of different materials. In yet another variant, the substrate is hollow.

In a preferred variant, the substrate is planar, so that the first and the second zone belong to the same plane. In another variant, the substrate is not planar and the first and the second zone belong to different planes. This last variant is more bulky than the first, but makes it possible to increase the degrees of freedom of the definition of the shape for the second zone 20.

The recess in a common substrate can be made by photo-lithographic techniques.

The shapes of zone 2 cut from the substrate are advantageously optimized so as to guarantee effective regulation of the position of the external point of the hairspring constituting zone 1, as well as effective regulation of the position of the center of gravity of this hairspring, so as to guarantee isochronism. Efficient regulation means that zone 2 is capable of deforming rapidly, with a sufficient amplitude of deformation, and without drift over time, depending on temperature and gravity for example.

The center of mass of the hairspring is mounted in a conventional manner on an axis on which the balance of the oscillating member is also assembled. In a variant, the balance of the regulating member is integrated into the common substrate 2.

According to the invention, the escapement, which aims to count the oscillations of the balance, and which periodically lets out a portion of the driving energy, for example from the barrel, to restore to the regulating member that that cause it to lose passive resistances (friction) while functioning as a distributor of energies, is also integrated in the plate. The escapement can for example be constituted by a portion which is elastically deformable, for example in translation. This deformation gives the balance the right to move in translation and to start. When the elastic portion returns, driven by the stored elastic energy, it pushes the balance back. The exhaust thus acts as a bistable system.

Reference numbers used in figures

1 Oscillating element 2 Substrate 10 First zone 20 Second zone 30 Holes M0,1,2,3 Simple geometric shapes

Claims (9)

1. Watchmaking assembly comprising: - an oscillating element (1) for a watch regulating organ, - an exhaust, characterized in that said oscillating element for a horological regulating member comprises: - a first zone (10) whose oscillations determine the course of said regulating member, - a second zone (20) distinct from the first zone (10), said second zone (20) being linked to the first zone and having a volume greater than the volume of the first zone, said second zone (20) has a shape arranged to compensate for the deformations of the first zone (10) caused by temperature, by temperature variations, by magnetic fields or by gravity in order to improve the isochronism of said regulating member watchmaker, and in that a common substrate comprises said oscillating element and said exhaust, said common substrate being in the form of a plate, said exhaust and said oscillating member being formed by recess in said common substrate (2). 2. Watch assembly according to claim 1, said escapement being constituted by a portion of said plate, said portion being elastically deformable, for example in translation. 3. Watch assembly according to claim 2, wherein said escapement acts as a bistable system. 4. Watch assembly according to one of claims 1 to 3, said first zone constituting a spiral spring. 5. Watch assembly according to one of claims 1 to 4, said second zone (20) comprising one or more holes (30) for positioning and / or fixing for fixing it to a plate. 6. Watch assembly according to one of claims 1 to 5, comprising a balance, wherein said common plate-shaped substrate comprises said balance. 7. Watch assembly according to one of claims 1 to 6, the substrate being made of a single material, for example silicon. 8. Watch assembly according to one of claims 1 to 6, the substrate comprising two or more layers of different materials. 9. Watch assembly according to one of claims 1 to 8, the substrate being hollow.