EP2394202B1 - Mechanical oscillating system for watches and functional element for watches - Google Patents

Description

The invention relates to a mechanical vibration system for watches according to claim 1.

It has already been proposed to manufacture the spring or balance spring (spiral spring) of a mechanical vibration system made of silicon and u.a. To provide mechanical strength and temperature compensation on their surfaces with a layer of silicon oxide. In particular, when the layer of silicon oxide is thermally cured, layer thicknesses that would be required for optimum temperature compensation, i. at layer thicknesses greater than 4 microns i.a. the risk of deformation, at least a partial deformation of the balance spring, which then leads to a deterioration of the accuracy of the vibration system and / or to non-reproducible conditions in the production.

The European patent application EP 1 445 670 A1 discloses a hospital spring of amorphous or crystalline material (silicon wafer). The winding cross-section of the spiral spring is 0.015 mm ² . The document does not mention anything regarding the structure of the vibration system and the grain size and other parameters of the balance spring.

The German translation of the European patent specification EP 0 732 635 B1 merely discloses that with the claimed method, a hospital spring for clockworks can be produced. The material of the base plate from which the micromechanical part is structured may be monocrystalline or polycrystalline silicon. The document does not mention anything regarding the structure of the vibration system and the grain size and other parameters of the balance spring.

The international patent application WO 2006/123095 A2 discloses the production of a spiral spring, wherein the individual turns of the coil spring are cut out by means of a laser. The spiral spring consists of an iron-nickel alloy.

The object of the invention is to show a vibration system which avoids these disadvantages. To solve this problem, a mechanical vibration system according to claim 1 is formed.

Functional elements in the context of the invention are in particular those of a mechanical oscillating system for watches and in particular for mechanical watches or wristwatches, namely in particular the spiral and balance spring, the oscillating body or the balance wheel, the shaft of the oscillating body, elements for fixing the balance spring on the oscillating body or Elements for attachment of the balance spring on the shaft of the oscillating body and on a circuit board of the movement, the so-called double disc on the shaft of the oscillating body for deflecting the armature, the armature and the escape wheel. Functional elements in the context of the invention are also gears of a movement generally.

According to one aspect of the invention, the mechanical vibration system for watches, especially for watches, from a balance spring and a balance wheel with a shaft for attachment of the balance spring. The balance spring is made of polycrystalline silicon with elongated grains resulting from the columnar growth. The elongated grains have a grain width in the range between 10 and 1000 nm and a grain length in the range between 2 and 50 microns. A winding cross-section of the balance spring is 0.001 mm ² to 0.3 mm ² .
According to one aspect of the invention, the grain length is in the range between 5 and 50 microns. The winding cross-section of the balance spring may be 0.001 mm ² to 0.01 mm ² or 0.001 mm ² to 0.03 mm ² . The coefficient of linear expansion of the balance spring is less than 8x10 ^-6 / K.
According to a preferred embodiment of the invention, the balance spring is provided on the outer surface of its windings with a thermally generated layer of silicon oxide. This layer has a maximum thickness of 4 microns, preferably of a maximum of 3 microns or smaller.
The balance spring is suitably fixed to the shaft with an inboard end, and an outboard end of the balance spring is held with a spring holder block on a spring holder that is adjustable by pivoting about an axis of the balance wheel.

According to one embodiment, the balance wheel consists of an outer ring, radially inwardly extending spokes and a central hub portion for attachment of the balance shaft. The balance wheel is made in one piece with the spokes and the outer ring. The outer ring has on its inside between the spokes formed mounting portions, wherein an adjustment element is provided at each attachment portion.
According to a further embodiment of the invention, the balance wheel or the balance spring form at least one bearing and / or sliding and / or mounting surface on which the surface of the balance wheel or the balance spring consists of an inner layer of silicon oxide and a DLC coating forming the outer surface consists. Between the outer layer formed by the DLC coating and the inner layer of silicon oxide, at least one single-layer or multi-layer metallic intermediate layer is provided, which consists, for example, of titanium nitride and / or titanium carbide and / or tungsten carbide.
In a further development of the invention, the oscillating body or balance wheel, for example, designed so that the adjusting elements are held by clipping or latching on the oscillating body or on the inside of the balance wheel or a ring of the balance wheel, and / or that the oscillating body of molybdenum or a molybdenum in made of a high proportion alloy, wherein the aforementioned features may be used individually or in any combination.

According to a further aspect of the invention is provided in a coil spring for a mechanical oscillating system for watches, the coil spring body in the region of its outer end with a multi-wave section, wherein the coil spring (balance spring) is executed in a further development of the invention, for example, that they made Silicon, and / or that it is made of polycrystalline silicon or a silicon ceramic, for example of silicon nitride,
wherein the aforementioned features of the coil spring may be used individually or in any combination.

• dass die Zentrierelemente jeweils von wenigstens einem um eine Achse parallel oder im Wesentlichen parallel zur Schwingachse dreh- oder schwenkbar am Massenkörper mit einem gegenüber der Dreh- oder Schwenkachse versetzten Massenschwerpunkt aufweisen,
• und/oder
• dass er speichenradartig ausgebildet ist,
• und/oder
• dass die Justierelemente durch Klipsen oder Verrasten am Schwingkörper bzw. an der Innenseite des Unruhrades oder eines Ringes des Unruhrades gehalten sind, und/oder
• dass er aus Molybdän oder einer Molybdän in einem hohen Anteil enthaltenden Legierung gefertigt ist,

wobei die vorgenannten Merkmale des Schwingkörpers jeweils einzeln oder in beliebiger Kombination verwendet sein können.According to a further aspect of the invention, the oscillating body or the balance wheel for a mechanical oscillating system for watches, in particular wristwatches, with attached to a radially outer region of the vibrating body adjusting elements for Setting the dynamic oscillatory moment of inertia of the oscillating body with respect to its oscillating axis, so executed, wherein the oscillating body is designed in a further development of the invention, for example, so

• in that the centering elements each have at least one about an axis parallel or substantially parallel to the swing axis rotatable or pivotable on the mass body with a relative to the rotational or pivot axis offset center of gravity,
• and or
• that it is formed Speichenradartig,
• and or
• that the adjusting elements are held by clipping or latching on the oscillating body or on the inside of the balance wheel or a ring of the balance wheel, and / or
• that it is made of molybdenum or an alloy containing molybdenum in a high proportion,

wherein the aforementioned features of the vibrating body can be used individually or in any combination.

Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and from the figures. In this case, all described and / or illustrated features alone or in any combination are fundamentally the subject of the invention, regardless of their summary in the claims or their dependency. Also, the content of the claims is made an integral part of the description.

• Fig. 1 in vereinfachter Funktionsdarstellung die wesentlichen Elemente eines mechanischen Schwingsystems einer Armbanduhr;
• Fig. 2 in Draufsicht die Spiralfeder des Schwingsystems der Figur 1 ;
• Fig. 3 in perspektivischer Teildarstellung ein mechanisches Schwingsystem für Uhren, insbesondere Armbanduhren gemäß einer weiteren Ausführungsform;
• Fig. 4 in Einzeldarstellung und in Draufsicht das Schwing- und Unruhrad des Schwingsystems der Figur 3;
• Fig. 5 in perspektivischer Darstellung und in Draufsicht eines der Zentrierelemente des Unruhrades des Schwingsystems der Figur 3;
• Fig. 6 in Einzeldarstellung einen Federhalter oder Halteklotz für die Spiral- oder Unruhfeder des Schwingsystems der Figur 3;
• Fig. 7 in vereinfachter Darstellung einen Schnitt durch eine mehrlagige Beschichtung auf einem aus Silizium hergestellten Funktionselement.

The invention will be explained in more detail below with reference to the figures of exemplary embodiments. Show it:

• Fig. 1 in a simplified functional representation of the essential elements of a mechanical vibration system of a wristwatch;
• Fig. 2 in plan view, the coil spring of the vibration system of FIG. 1 ;
• Fig. 3 in a perspective partial view of a mechanical vibration system for watches, in particular wristwatches according to another embodiment;
• Fig. 4 in individual representation and in plan view of the oscillating and balance wheel of the vibration system of FIG. 3 ;
• Fig. 5 in a perspective view and in plan view of one of the centering of the balance wheel of the oscillating system of FIG. 3 ;
• Fig. 6 in an individual representation of a spring holder or retaining block for the spiral or balance spring of the vibration system of FIG. 3 ;
• Fig. 7 in a simplified representation of a section through a multilayer coating on a functional element made of silicon.

The vibration system generally designated 1 in the figure consists of the spiral spring 2 and of the oscillating or balance wheel 3. The balance spring 2 is made of silicon, preferably of polycrystalline silicon. The preparation of the balance spring 2 is carried out, for example, from a non-metallic crystalline or sintered material having a particle size in the range between 10 and 50,000 nm, preferably between 10 - 10.000nm, wherein Columnen-growth, the grain size, for example, a length of about 5 - 50μm and has a width of 10 -1,000nm. Furthermore, the non-metallic crystalline or sintered material has a thermal coefficient of linear expansion of less than 8 10 ^-6 / K or the balance spring 2 is using a wafer made of this material or silicon, for example by cutting and / or etching (masking and etching). The wafer is produced, for example, by epitaxial deposition of silicon. The cross-sectional area of the spring coil is, for example, 0.001-0.01 mm ² .

The balance spring 2 is provided on the outer surface of its turns with a e.g. provided thermally generated layer of silicon oxide. This layer has a maximum thickness of 4 microns, preferably of at most 3 microns or smaller.

The oscillating mass or the oscillating body, ie the oscillating or balance wheel 3, which has, for example, the usual spoked wheel-like form for such wheels, is made of Molybdenum or made of an alloy with a high molybdenum content. The combination of silicon (for the balance spring 2) and molybdenum (for the balance wheel 3) results in an optimally temperature-compensated mechanical vibration system, ie a mechanical vibration system whose gear or frequency accuracy is, in particular, independent of changes in temperature.

The FIG. 2 shows the coil spring 2 again in an individual representation. A special feature of this coil spring is that it is designed in the area of its outer spring end at 2.1 multiple wave-shaped. This area results in an improved, very uniform vibration behavior of the spiral spring 2.

The spiral spring 2 with the section 2.1 is also advantageously used for oscillating systems of watches, in particular wristwatches, in which the oscillating mass is designed differently than described above.

The FIG. 3 shows a perspective view of a vibrating system 1 a with the coil spring 2a and the oscillating or balance wheel 3a. The balance spring 2a and the balance wheel 3a are made of the same material and / or in the same manner as described above for the coil spring 2 and the balance wheel 3.

The balance wheel 3a is designed spoke-like, consisting of an outer ring 4, four radially extending from the ring 4 inwardly extending spokes 5 and a central hub portion 6, which has the opening 6.1 for attachment of the balance shaft and integral with the spokes 5 and the outer ring 4 is made.

The outer ring 4 is formed on its inside with a circumferential groove 7 and between the spokes 5 each having a fork-like attachment portion 8. At each mounting portion 8, an adjusting element 9 is provided, which is made in one piece of a non-magnetic metallic material, such as molybdenum or a corrosion-resistant steel. With the adjusting elements 9, as well as the spokes 5 at regular angular intervals about the axis of the balance wheel 3a and the Opening 6.1 are arranged distributed, the relevant for the frequency or oscillation period of the vibration system dynamic moment of inertia of the balance wheel 3a can be adjusted. The attachment portion 8 are each provided below the groove 7.

For this purpose, the adjusting elements 9 consist of a circular-disk-shaped body 10 with a pin 11 which is arranged coaxially with the axis of this body and projecting beyond an end face of the centering element 9 with a circular-cylindrical outer surface. Furthermore, in the body 10 is a continuous, i. open and arcuately curved recess 12 is provided on both end faces of the disk-shaped body 10, which extends over an angular range of slightly less than 180 ° about the axis of the centering element 9, in such a way that the centering element 9 and its body 10 at its periphery has a continuous edge, the center of mass of the centering element 9 but is offset radially to the axis of the centering element 9. At the top 11 facing away from the pin 11, the body 10 is further provided with a slot-shaped, radially or approximately radially to the axis of the centering extending recess 13, which forms the attack or actuating surface for a setting workpiece, such as a screwdriver. With the pin 11, each centering element is rotatably provided on a mounting portion 8 about an axis parallel to the axis of the balance wheel 3a, with a certain stiffness in that the respective pin 1 1 is held by snapping or latching on the fork-like mounting portion 8 and each Adjusting element 9 extends on the periphery with its disc-like body 10 in the groove 7, where it is secured axially and bears radially against the bottom of the groove.

The assembly of the adjusting elements 9 on the ring 4 is thus carried out such that each adjusting element 9 is pushed with its pin 1 1 radially on the associated fork-like mounting portion 8. By turning or pivoting the adjusting elements 9 about the axis of their pins 1 1, the center of mass of each adjusting element u.a. displaced radially to the axis of the balance wheel 3a and thereby set the dynamic moment of inertia in the desired manner. After adjustment of the adjusting elements 9 they are fixed by a suitable adhesive or fixing lacquer.

The balance spring 2a is fastened with the inner end in a suitable manner to the balance shaft, not shown. The outer end of the coil spring 2a is at a Federhalterklötzchen or block 14 held by pivoting about the axis of the balance wheel 3a adjustable spring holder 15.

How the particular FIG. 6 it can be seen, the spring holder block 14 made of metallic material is a section 14.1, with which it can be secured in an opening 16 of the spring holder 15 by clipping or latching, as well as with a section 14.2 with two fork or clamping arms 17 and 18 executed, which form between them a clamping gap 19, in which the coil spring 2a can be fixed by clamping. The clamping gap 19 is open to the underside facing away from the portion 14.1 as well as to two opposite end faces of the spring holder block 14 and on the side facing the portion 14.1 bounded by a surface 20.1.

In the assembled state, the spring holder block 14 is oriented with its longitudinal extent parallel to the axis of the balance wheel 3a. During assembly of the oscillating system, the outer portion of the coil spring 2a of the section 14.1 or

Pen holder 15 opposite bottom of the spring holder block 14 forth introduced into the nip 19. Thus, the coil spring 2a is already held on the spring holder 15 mounted on the spring holder block 14 such that even a change and adjustment of the effective spring length, which is required for the frequency of the mechanical vibration system by moving the coil spring 2a relative to the spring holder block 14 while maintaining the clamp connection is possible. After this adjustment, the connection between the coil spring 2a and the spring holder block 14 is fixed, again using a suitable adhesive or fixing varnish.

The adjusting elements 9, but in particular the respective spring holder block 14 are preferably manufactured as so-called LIGA parts with the LIGA method known to those skilled in the art, which allows the production of metallic moldings with very small dimensions by the process steps lithography, electroplating and impression.

In the FIG. 7 schematically the formation of a bearing and / or escort and / or mounting surface of a functional element 21 reproduced, which consists of silicon, preferably polycrystalline, for example, epitaxially deposited polycrystalline silicon. The bearing and / or sliding and / or mounting surface forming surface 22 of the functional element 21 is formed by a multilayer coating, at least consisting of a directly adjoining the silicon material of the functional element 21 coating 23 of silicon oxide, for example by thermal Oxidation or produced in any other suitable manner. The coating 23 is followed by a metallic intermediate layer 24, which preferably consists of titanium nitride and / or titanium carbide and / or tungsten carbide and is applied, for example, in a PVD coating process. The intermediate layer 24 may in turn be designed in a multi-layered manner, specifically in several individual layers, for example, of the abovementioned materials. The intermediate layer 24 is followed by a coating 25 forming the actual outer surface, which is embodied as a DLC coating and produced, for example, by CVD deposition. The invention is based on the finding that improved adhesion of the layer 25 to the layer 23 is achieved by the metallic intermediate layer 24, so that the layer 25 is effectively prevented from flaking or loosening by the functional element 21 during assembly and during use of a clock , This is true not only for storage and sliding surfaces, but especially for mounting surfaces and especially for those with or on which a clamping attachment is done, such as a clamping attachment of the spiral or balance spring or the oscillating body to a shaft, etc.

The invention has been described above by means of exemplary embodiments. It is understood that numerous changes and modifications are possible without thereby departing from the inventive concept underlying the invention. Instead of the aforementioned silicon material (eg polycrystalline silicon), in particular a sintered material based on silicon or silicon sintered material and / or the non-metallic crystalline or sintered material with the grain size in the range between 10 and 50 000 nm and with the thermal expansion coefficients smaller 8 x 10 ^-6 / K.

LIST OF REFERENCE NUMBERS

• 1, 1 a mechanical vibration system
• 2, 2a balance spring
• 3, 3a balance wheel
• 4 tires or ring
• 5 spoke
• 6 hub-like section
• 7 groove
• 8 fixing section
• 9 adjustment element
• 10 disc-shaped body of the adjusting element. 9
• 1 1 pin of the adjusting element 9
• 12 recess
• 1 3 slot
• 14 spring holder blocks
• 14.1, 14.2 section of the spring holder block
• 15 pen holder
• 16 opening
• 17, 18 clamping arm
• 19 nip
• 20 contact surface
• 21 functional element
• 22 surface of the functional element 21st
• 23, 24, 25 coating or layer

Claims (10)

1. A mechanical oscillation system for clocks, in particular wristwatches, having a balance spring (2, 2a) and a balance wheel (3, 3a) having a shaft for fastening the balance spring (2, 2a), wherein
   the balance spring (2, 2a) consists of polycrystalline silicon having elongated grains, which result because of column growth, and the elongated grains have a grain width in the range between 10 and 1000 nm and a grain length in the range between 2 and 50 µm; and a turn cross section of the balance spring (2, 2a) is 0.001 mm² to 0.3 mm².
2. The mechanical oscillation system according to Claim 1, wherein the grain length is in the range between 5 and 50 µm.
3. The mechanical oscillation according to any one of the preceding claims, wherein the turn cross section of the balance spring (2, 2a) is 0.001 mm² to 0.01 mm² or 0.001 mm² to 0.03 mm².
4. The mechanical oscillation system according to any one of the preceding claims, wherein the coefficient of linear expansion of the balance spring (2, 2a) is less than 8 x 10^-6/K.
5. The mechanical oscillation system according to any one of the preceding claims, wherein the balance spring (2, 2a) is provided on the external surface of the turns thereof with a thermally produced layer made of silicon oxide and this layer has a thickness of at most 4 µm, preferably at most 3 µm or less.
6. The mechanical oscillation system according to any one of the preceding claims, wherein the balance spring (2, 2a) is fastened with an inner end in a suitable manner to the shaft and an outer end of the balance spring (2, 2a) is held by a spring holder block (14) on a spring holder (15), which is adjustable by pivoting about an axis of the balance wheel (3, 3a).
7. The mechanical oscillation system according to Claim 1, wherein the balance wheel (3, 3a) consists of an outer ring (4), spokes extending radially inward (5), and a middle hub section (6) for fastening the balance shaft, and wherein the balance wheel (3, 3a) is produced in one piece with the spokes (5) and the outer ring (4).
8. The mechanical oscillation system according to Claim 7, wherein the outer ring (4) has fastening sections (8) formed on its inner side between the spokes (5), wherein an adjustment element (9) is provided on each fastening section (8).
9. The mechanical oscillation system according to any one of the preceding claims, wherein the balance wheel (3, 3a) or the balance spring (2, 2a) form at least one bearing and/or sliding and/or installation surface, at which the surface (22) of the balance wheel (3, 3a) or the balance spring (2, 2a) consists of an inner layer (23) made of silicon oxide and a DLC coating (25), which forms the outer surface.
10. The mechanical oscillation system according to Claim 9, wherein at least one single layer or multilayer metallic intermediate layer (24), which consists of titanium nitride and/or titanium carbide and/or tungsten carbide, for example, is provided between the outer layer formed by the DLC coating (25) and the inner layer (23) made of silicon oxide.

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