JP2012242382A - Balance wheel for timepiece and mechanical timepiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balance wheel (1) comprising a balance mass (10) rotatable about the axis of rotation, preferably parallel to the axis of oscillation of the balance wheel, relatively to a balance wheel body.SOLUTION: A balance mass has the center of gravity off and distant from the axis of rotation, and is made of two different materials (11, 12) having different densities.

Description

  The present invention relates to a flywheel for a mechanical watch and a watch having such a flywheel.

  It is known to balance a watch flywheel, for example by means of a milled recess or by adjusting one or more set screws. It is also common to balance flywheels by removing material (eg, by milling) from the flywheel rim. This process is not reversible. Furthermore, fine adjustment of the watch may be performed via an adjuster.

  Such an adjuster may have some problems due to inevitable play, so a counterweight (also called a counterweight or “maslot”) distributed in a distributed manner on a flywheel in a mechanical watch. It is also known to provide an adjusting screw. The balancing mass or adjusting screw on the one hand makes it possible to compensate for the unbalance and on the other hand allows the moment of inertia of the flywheel and thus the vibration frequency of the flywheel and spiral spring vibration system to be adapted. Among these balancing masses, in particular, balancing masses are known which can be fixed or arranged on the flywheel in a distributed manner in the peripheral direction. This fixing is performed by putting a continuous body such as a pin in the corresponding recess of the flywheel. As a result, the shape of the balance mass is generally not rotationally symmetric with respect to rotation about the axis of the continuum, such as the pin, so one or more rotations of these counterweights compensate for the unbalance. And / or the flywheel moment of inertia can be adapted. Examples for such solutions can be found in WO 2010/088891 or GB 845773.

  Disadvantages of these solutions are on the one hand the manufacturing costs of asymmetrically shaped counterweights and on the other hand the additional air resistance caused by these counterweights. This contributes to damping of the vibration system.

  Progressing from the state of the art, it is an object of the present invention to provide an improved flywheel that does not include, or to a lesser extent, at least one of the disadvantages described above.

  This object is achieved by the invention described in the claims.

  A flywheel according to one aspect of the present invention includes a flywheel body (generally having a flywheel rim and flywheel spokes), a flywheel body mounted on the flywheel body and rotatable about an axis of rotation, preferably vibration of the flywheel. One balancing mass or a plurality of balancing masses parallel to the axis, the balancing masses being two different in such a way that the center of gravity does not exist on the axis of rotation but is away from it Manufactured from different materials with density.

  For example, the balancing mass is regularly distributed in the peripheral direction, but an irregular arrangement using, for example, different balancing masses is also conceivable.

  For the simplest possible adjustments or adjustments, the balancing masses are preferably present in pairs, for example 2, 4, 6, 8, or more balancing masses symmetric with respect to the vibration axis Arranged. It is particularly preferred that there are 4 or 8 balancing masses. Because the adaptation is simplified. Four balancing masses are particularly preferred.

  Depending on the requirements, it can be envisaged to fix the counterweight on the flywheel rim in an offset manner with respect to the spokes. In a four-spoke flywheel, for example, the mass in each case may be in the middle between the two spokes. Thus, for certain configurations, a two-spoke or four-spoke flywheel combined with a treatment according to the present invention is preferred. However, a three-spoke flywheel is also possible.

  However, it is also possible to fix the balance mass on the flywheel spokes or elsewhere.

  The balancing mass is preferably fixed so that it can rotate 360 °. The balancing mass may include one engagement opening or several engagement openings for the rotary tool, the arrangement and / or shape of the openings being not rotationally symmetric with respect to the axis of rotation.

  Neglecting one such engagement opening or several engagement openings, the geometric outer shape may be rotationally symmetric or may have at least n-fold rotational symmetry. . That is, it may be symmetric with respect to rotation about a defined fraction of 360 °.

  Similarly, in many embodiments, the volume centroid (also referred to as the geometric midpoint or geometric centroid of the body; corresponding to the assumed centroid of the body of the same material but of the same quality) is on the axis of rotation. Exists. That is, an eccentric mass center (mass midpoint) is obtained exclusively by the arrangement of at least two materials.

  This measure also allows the overall balance mass to be essentially disk-shaped, in particular retained along its cylindrical lateral surface (for example, relative to the distance to the outermost rotation axis). Allows to be done. In particular, the holding means on the flywheel body may partially engage around the lateral surface.

  Therefore, according to the above embodiment, no pin protruding in the axial direction is particularly required to fix the balance mass. This allows a particularly compact mounting of the balance mass. Such mounting is also optimal for the lowest possible air resistance, and the attenuation caused thereby is preferably kept small.

  In particular, the axial extension of the complete arrangement of the balance mass and the receiving part may be equal to or smaller than the axial extension of the flywheel rim, and its axial extension. The balancing mass for may not be projected beyond the flywheel rim.

  In an embodiment, the holding means are designed such that the balancing mass is fixed on the flywheel by axial movement and is fixed axially, for example by friction of the holding means on the lateral surface. In this case, the holding means may include an axial contact portion that restricts axial movement in one direction. Complementary or alternatively to this friction, a clip mechanism may also be applied to fix the balance mass in the axial direction.

  In an alternative embodiment, the holding means may further comprise a guide opening in the flywheel body. In this opening, a corresponding axially projecting pin in the balancing mass projects and is held. The reverse procedure is also conceivable (for example, the balancing mass has a continuous guide opening that engages the pin of the flywheel body).

  The balancing mass produced from at least two materials may for example be produced by molding techniques known per se, such as casting with galvanic. A manufacturing technique is conceivable in which both parts are manufactured individually and then fixed together.

  Considering the selected manufacturing technique above, all material combinations of at least two solid materials with the most significant density difference possible may be applied. An example of a material combination is a nickel-phosphorus / gold combination.

  Embodiments of the present invention will be described in more detail with reference to the drawings. The same reference numbers refer to the same or similar elements in the drawings. The drawings are not all at the same scale.

It is a figure of a flywheel. It is a figure of the balance mass. It is a figure of the aspect which the balance mass functions. It is a figure of the implementation example about fixation of the balance mass on the main body of a handwheel. It is a figure of the implementation example about fixation of the balance mass on the main body of a handwheel. It is a figure of the implementation example about fixation of the balance mass on the main body of a handwheel. It is a figure of the implementation example about fixation of the balance mass on the main body of a handwheel. FIG. 6 is a further example of realization of fixing the balance mass on the flywheel body. FIG. 6 is a further example of realization of fixing the balance mass on the flywheel body. FIG. 6 is a further example of realization of fixing the balance mass on the flywheel body. FIG. 6 is a further example of realization of fixing the balance mass on the flywheel body. FIG. 6 is an alternative balancing mass diagram. FIG. 6 is an alternative balancing mass diagram. FIG. 6 is an alternative balancing mass diagram. FIG. 6 is an alternative balancing mass diagram. FIG. 6 is an alternative balancing mass diagram.

  The flywheel 1 shown in FIG. 1 is shown without a balance member and includes four flywheel spokes 3 (webs) in addition to the flywheel rim 2. Of course, embodiments of the present invention may also be applied to flywheels having more than two, three, or four flywheel spokes. The central guide opening 4 serves to receive the balancing member and thus its center defines a vibration axis (perpendicular to the plane spanned by the flywheel spokes and the flywheel rim).

  On the inside, a receiving part 5 for the balance mass 10 is present on the flywheel rim. These receiving portions are uniformly distributed over the peripheral portion of the flywheel rim, and specifically, preferably are distributed in a paired manner. For simple balancing and adjustment capabilities, 4 or 8 balancing masses and thus 4 or 8 receiving parts are preferred. In the embodiment shown, four receiving parts are each centered between the flywheel spokes.

The balance mass 10 is shown more clearly in FIG. The balancing mass 10 is disk-shaped and consists of two different materials with different densities. Here, the first material 11 is gold having a density of 19.3 g / cm ³ , and the second material 12 is significantly lower in density (the density of nickel: 8.9 g / cm ² ). Some nickel-phosphorus. Each of these two materials takes up approximately half of the volume of the disk. Here, the dividing line between the parts formed by the two materials does not extend in a straight line, the two parts are fixed to each other, and the edges of these materials are brought into close contact with each other Are selected to mesh with each other. As in the illustrated embodiment, an undercut may be further formed so that these two parts are secured together via a positive fit.

  The balancing mass here has an engagement opening 14 for the tool, which is a slot that simultaneously separates the two parts from each other in the middle region. The engagement openings in this example and in the examples of later examples simplify the rotation of the balance mass when the balance mass is fixed on the flywheel 1.

  The geometrical midpoint is located at the center of the disc-shaped balance mass, i.e. on the symmetry axis of the outer lateral surface (if the engagement opening is ignored). This intermediate point corresponds to the rotation axis 13 of rotation in the receiving part. However, since the density is not uniform, the center of gravity (mass center) is not located on the rotating shaft 13 and is displaced toward the heavier first material 11.

  The functional aspect of the balance mass 10 is schematically illustrated in FIG. Balance with respect to the vibration axis of the flywheel 1 by rotation about the rotation axis (extending through the center of the balance mass, here parallel to the vibration axis of the flywheel and perpendicular to the drawing in FIG. 3) The center of gravity of the mass 10 can be displaced, thereby changing the rotational moment of inertia of the flywheel (including the balance mass). The inertial moment of rotation can be increased by rotating the heavy gold portion outwardly toward the flywheel rim, thus increasing the resonant frequency of the flywheel and spiral spring vibration system. On the contrary, when this heavy material exists inside, that is, closer to the vibration axis, the inertial moment of rotation becomes smaller. Unbalance compensation or balancing is performed in a similar manner.

  4-6 illustrate an example of how the balancing mass 10 can be secured on the flywheel body (ie, on the rim and / or spoke). Each of the receiving parts 5 includes two receiving part legs 6. The inner surface of the receiving leg 6 is shaped according to the lateral surface of the counterweight 10 and at least partially surrounds it. On the lower side, the receiving plate 7 protrudes inwardly beyond the receiving portion leg portion 6. The receiving plate 7 is an example of an axial contact portion with respect to the balance mass. The balancing mass can be secured by axial movement (“downward”). At the time of fixing, the receiving portion leg is slightly elastically curved outward, and the axial contact portion accurately defines the position of the end portion in the axial direction.

  If necessary depending on the material of the receiving part 5, the elasticity may be further increased by selecting the shape of the receiving part. This is shown schematically in FIG. In FIG. 7, in each case, a notch 9 is present in the receiving part on both sides of the balancing mass at the base of the receiving part leg 6. Therefore, the two receiving part leg parts 6 can be bent with a reduced resistance as compared with the case where there is no notch.

  The embodiment of FIG. 8 and the embodiment of FIG. 9 (where the balance mass and flywheel body are partially shown in cross-section) are the means by which the balance mass is held on the flywheel body. Different in. The flywheel body includes a pin 8. The balancing mass is secured to the pin 8 by a central, here axially continuous opening 20. The opening 20 defines a rotation axis. In the embodiment shown, the opening 20 includes a plurality of radial ridges 17 so that the balancing mass 10 is only guided at the position of the protrusion 18 formed therebetween. With this design, the elasticity of the guide is increased compared to the result of the cylindrical opening, and very high demands on manufacturing tolerances are required.

  The flywheel spoke 3 forms an axial abutment when the balancing mass is secured onto the flywheel body. Other solutions are possible.

  In the example embodiment according to FIG. 9, the continuous opening and this axis of rotation coincide with the axis that is centered, i.e. passes through the geometric midpoint. On the other hand, in the modification according to FIG. 10, the rotation axis 13 is arranged at a distance x from the axis 21 passing through the geometric midpoint. That is, the balancing mass is mounted in an eccentric manner. By rotating around the axis of rotation, this may increase the effect on the inertial moment of rotation and / or the effect on unbalance or its compensation.

  FIG. 11 shows an embodiment in which the balancing mass includes a peripheral collar 19 in contrast to FIG. The peripheral collar portion 19 exists on the receiving portion leg portion 6 after being fixed on the balance mass, thereby forming an axial contact portion. Accordingly, the receiving plate of the embodiment of FIG. 5 may be omitted, which further reduces the manufacturing cost of the flywheel.

12 and 16 further show alternative forms of the balance mass 10. These are characterized by the following characteristics:
a. The volume of the two materials 11, 12 is not roughly the same, but one of these materials, here the second material 12, bears a significantly larger volume than the other volume (FIGS. 12, 14-14). 16).
b. The structure of the two material parts that mesh with each other is changed. In FIG. 12, the second material is selected to include protruding undercut ridges 17 that engage corresponding structures of the first material. However, the shape of the partition surface between the two materials may be changed infinitely or may be flat (FIG. 13). In the balancing mass produced using galvanic technology, in particular the partition surface may be almost “vertical”, ie symmetrical in the translational direction in the axial direction. This is because it is the easiest to manufacture for manufacturing technology. However, partition surfaces other than vertical partition surfaces are also conceivable.
c. Several engagement openings which may further have a circular cylindrical shape (FIGS. 14 and 15) instead of a single, eg slot-like engagement opening 14 as in FIGS. 14 exists.
d. The engagement opening 14 is between the materials (FIGS. 2, 12, 13), only in one of the two materials (FIG. 14), or in the first and second materials (FIG. 15).
e. Instead of, or in addition to, the engagement openings 14 present in the balance mass, the engagement openings 14 may be further formed by peripheral grooves (FIG. 16).
f. The first and second materials are dispersed such that the peripheral outer surface is formed by only one of the two materials. By this means, the transition portion between the two materials does not come into contact with the receiving portion leg 6 around the receiving portion when rotation of the balance mass in the receiving portion is given (FIGS. 14 to 16).

  These features may be combined with each other in a practically infinite manner, and may have a different arrangement from that shown. The feature f. Or feature a. Neither of these need necessarily be present (as in FIG. 12 / FIG. 13, FIG. 14, FIG. 15, FIG. 16). It may also be combined with the configuration and may be the case of a partition surface without portions engaging each other. The same is true for feature f. And features and f. Applies to configurations that do not have Features a. -Feature f. All combinations of are conceivable.

  In the example shown, the two materials are arranged so that they can be seen when both materials are viewed from the top, i.e. when viewed from the axial direction. This is preferred because it allows optical orientation. This can simplify the adjustment. However, this feature is not essential. For example, to obtain a certain aesthetic effect, the entire balance mass may actually be coated with one of the two materials or a third material.

If neglected, a balanced mass with more than two materials is possible.
Instead of the gold and nickel-phosphorus material combinations described above, infinite combinations of other materials are possible. A combination of two materials of different densities that can be precipitated by galvanic is preferred. However, this is not essential. Thus, for example, one of the two materials may be further formed by plastic, and preferably the entire balance mass is coated with a metal that precipitates, for example, in a chemical manner.

Claims (16)

  A flywheel (1) for a watch comprising a flywheel body and at least one balancing mass (10) rotatable about the axis of rotation relative to the flywheel body, the balancing mass being different Manufactured from at least two different materials (11, 12) having a density, wherein the arrangement of the different materials is asymmetric with respect to rotation about the axis of rotation and the center of gravity of the balancing mass is the rotation Handwheel (1), characterized in that it is performed in a manner that does not exist on the shaft.   The flywheel according to claim 1, characterized in that there are several balancing masses (10), the balancing masses being arranged in pairs with respect to the oscillation axis of the flywheel (1).   The flywheel according to claim 1 or 2, characterized in that there are several balancing masses (10) arranged in contrast to the vibration axis.   The flywheel according to any one of claims 1 to 3, characterized in that the balancing mass (10) is rotatable approximately 360 °.   The shape of the counterbalance mass (10), excluding the optional engagement opening (14) for the rotary tool, is rotationally symmetric about the axis of rotation or approximately at an angle to the rotation. The flywheel according to any one of the preceding claims, characterized in that it is symmetrical.   The flywheel according to any one of the preceding claims, characterized in that a geometric midpoint of the balancing mass (10) lies on the axis of rotation.   The balance mass (10) according to any one of the preceding claims, characterized in that it is essentially disk-shaped without the optional engagement opening (14) for the rotary tool. The flywheel described in 1.   6. The method according to claim 1, wherein the balancing mass is held by holding means surrounding the balancing mass at least partly along a peripheral lateral surface. The listed flywheel.   9. Handwheel according to claim 8, characterized in that the holding means comprise two receiving leg (6) at least partly surrounding the lateral surface.   The flywheel according to claim 9, characterized in that the balance mass (10) can be transported between the receiving leg (6) by movement in the axial direction.   11. A flywheel according to any one of claims 8 to 10, characterized in that the at least one balancing mass includes a peripheral collar (19) forming an axial abutment.   The flywheel according to any one of claims 1 to 7, wherein the balance mass is held on the flywheel body by a pin guided through a guide opening.   The balance mass can be fixed on the flywheel body by movement in the axial direction with respect to the rotating shaft, and the flywheel body forms contact portions (7, 9) for this axial movement. A flywheel according to any one of the preceding claims, characterized in that   A flywheel according to any one of the preceding claims, characterized in that the first (11) of the materials is gold and the second (12) is a nickel alloy.   A mechanical timepiece comprising a flywheel (1) according to any one of the preceding claims and a spiral spring with which the flywheel together forms a vibration system.   16. A mechanical timepiece according to claim 15, characterized in that the spiral spring is connected to the flywheel (1) without a regulator.