JP2015049142A - Trank roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems, for example, when a trank roller is formed by processing a silicon material, if adjustment of inertia moment and a piece weight is required, it is impossible because silicon is a brittle material.SOLUTION: The trank roller body is formed by processing a substrate mainly formed of silicon. On at least one plane of the trank roller, a metal structure formed of a lower metal film which tightly contacts silicon, and an upper metal film which tightly contacts the lower metal film and is formed of a material different from that of the lower metal film, is provided. The metal structure can be formed into a columnar shape, a prismatic shape, a band shape or a ring shape, and plural metal structures can be provided. For adjusting inertia moment and a piece weight, the metal structure is removed.

Description

  The present invention relates to a balance wheel used in a speed governor of a mechanical timepiece.

  In a mechanical timepiece, a speed governor composed of a hairspring and a balance wheel is used in order to keep the operation of the machine at a regular and constant speed. The balance wheel regularly reciprocates by the expansion and contraction of the isochronous balance spring.

  The balance with the escapement composed of escape wheel and ankle is connected to the balance, and energy is transmitted from the balance spring through this escapement to sustain the vibration. Yes.

  In recent years, attempts have been made to manufacture timepiece parts by etching a silicon substrate. It is said that it has the advantage that it can be made lighter than the manufacture of watch parts using conventional metal parts, and the advantage that it can be mass-produced at low cost. Thereby, it is expected that a small and lightweight watch can be manufactured.

  When etching a silicon substrate, a reactive ion etching (RIE) technique, which is a dry etching technique, has recently progressed. Among them, deep RIE (Deep RIE) technology has been developed, and etching with a high aspect ratio has become possible.

  This technique allows the mask pattern to be faithfully reproduced in the vertical depth direction because the etching does not go under the portion masked with the photoresist, and when the silicon substrate is etched, the watch part is designed as designed. It has become possible to manufacture accurately with this shape.

  Since silicon has better temperature characteristics than metal, it is particularly advantageous when applied to a time governor. Above all, since the balance wheel constituting the balance must be regularly reciprocatingly rotated, if the balance wheel is composed of silicon, there is an advantage that it is not affected by temperature change.

  However, since silicon is a brittle material, it is difficult to machine, and has the disadvantage of low density, so that the moment of inertia necessary for a balance wheel cannot be obtained as it is.

  Therefore, a technique for increasing the inertia of the balance wheel by depositing metal in a ring shape made of silicon is known (for example, see Patent Document 1).

JP-T-2011-525614 (page 6-8, FIG. 6-9)

  However, the metal layer directly deposited on the balance wheel made of silicon in Patent Document 1 has a problem that the adhesion with silicon is not good because the coefficient of thermal expansion is different from that of silicon.

For this reason, the metal layer may peel off while being incorporated in a watch and operating as a watch. Then, it was found that the peeled metal layer could enter the timepiece mechanism and cause a malfunction.

  In addition, this is not only true for the prior art disclosed in Patent Document 1, but when the balance wheel is made of silicon, it is adjusted when there is a weight balance bias called a single spindle on the temporary balance wheel. It cannot be done. This is because, as described above, silicon is a brittle material and therefore cannot be machined substantially.

  In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a time governor for a timepiece that has a moment of inertia necessary for a balance wheel and does not cause an operation trouble of the timepiece mechanism even if it is a silicon balance wheel. To provide a balance wheel.

  The balance wheel according to the present invention for achieving the above-described object employs the following configuration.

  A balance wheel that engages and cooperates with a rotating shaft that constitutes a time governor for a watch, and is a substrate mainly composed of silicon in which a fitting portion that fits the rotating shaft and an outer peripheral portion are integrated. A metal structure is provided on the plane of the substrate perpendicular to the axial direction of the rotation axis, and the metal structure has a lower metal film in close contact with the substrate and an upper metal film of different materials in close contact with the lower metal film. It is characterized by being laminated.

  With such a configuration, the metal structure has good adhesion to a substrate mainly composed of silicon and does not peel off. Further, even when, for example, a single weight is generated and it is necessary to remove a part of the metal structure for the adjustment, the metal structure is provided on the plane of the substrate. be able to. If the metal structure is intentionally removed, the balance of the balance wheel and the moment of inertia can be adjusted.

  Further, the lower metal film and the upper metal film are preferably made of a metal having a specific gravity greater than that of the substrate.

  With this configuration, the moment of inertia of the balance wheel can be easily increased.

  Further, the metal structure may be in a bump shape.

  With such a configuration, a plurality of bumps can be disposed along the outer periphery of the balance wheel. Also, when adjustment of the single spindle occurs, it can be removed by pushing this metal structure from the side, etc., so the balance between the single spindle of the balance wheel and the moment of inertia can be adjusted easily. Convenient.

  The metal structure is preferably in the shape of a band.

  With such a configuration, for example, a metal structure can be formed with a larger area because it can be provided between the fitting portion that fits with the rotation shaft of the balance wheel and the outer peripheral portion.

  Further, the metal structure may have a ring shape having concentric rotation axes.

  With such a configuration, for example, it can be provided along the outer peripheral portion of the balance wheel, and a metal structure can be formed with a larger area.

  Moreover, you may provide a lower layer metal film in the whole surface of a plane.

  Such a configuration is convenient because a metal structure can be formed simply by providing an upper metal film in an arbitrary portion.

  Further, when a virtual straight line passing through the center of the rotation axis is drawn in parallel to the plane of the substrate and the area of the plane is divided, the weight of the metal structure in the divided area may be the same between the areas.

  By adopting such a configuration, the balance wheel can be configured with no balance of the balance wheel.

Even if the balance wheel of the present invention is a balance wheel mainly composed of silicon, it has a moment of inertia necessary for a balance wheel, does not cause an operation trouble of the timepiece mechanism, and can eliminate a single weight.
Since the metal structure can be easily removed when attempting to remove it, it is possible to adjust the balance of the balance wheel and the moment of inertia.

It is a top view of the balance wheel of the governor for timepieces which is the 1st Embodiment of this invention. It is sectional drawing of the balance wheel shown in FIG. It is a side view which shows the structure of the governor for timepieces of this invention. It is a top view of the balance wheel of the governor for timepieces which is the 2nd Embodiment of this invention. It is sectional drawing of the balance wheel shown in FIG. It is sectional drawing explaining the shape of the metal structure which is the 3rd Embodiment of this invention.

Hereinafter, a balance wheel of a time governor for a timepiece according to an embodiment of the present invention will be described in detail with reference to the drawings.
In the description, an example in which two metal films constituting a metal structure have the same shape will be described as the first embodiment. As a second embodiment, an example in which the shapes of two metal films are different will be described. As a third embodiment, a further different shape of the metal structure will be described.

[Description of the structure of the balance wheel of the first embodiment: FIGS. 1 and 2]
First, the structure of the balance wheel in the first embodiment will be described with reference to FIGS. 1 and 2.
FIG. 1A shows a shape of a balance wheel that is generally known. By connecting a fitting portion 2a and a peripheral portion 2b that are fitted to a rotating shaft (not shown) by a connecting portion 2c, the balance wheel body 2 is shown. It is a top view which shows the balance wheel 4 which has the hole 2d in a plane.
FIG.1 (b) is a top view which shows the balance wheel 4 which does not have the hole 2d and the balance ring body 2 becomes a uniform planar structure.
2 is a cross-sectional view showing a cross section cut along a virtual straight line L (two-dot chain line) passing through the center of the balance wheel body 2. FIG. 2 (a) is a cross-sectional view of FIG. ) Corresponds to FIG.

  The balance wheel 4 shown in FIGS. 1 and 2 has a structure in which a metal structure 3 is provided on a balance body 2 formed by etching a semiconductor substrate containing silicon as a main component. The balance wheel body 2 has a thickness of 450 μm, for example. The metal structure 3 includes a lower metal film 3a that is in close contact with the balance wheel body 2 and an upper metal film 3b that is in close contact with the lower metal film 3a.

1 (a) and 2 (a) has a fitting portion 2a having a through hole 4a that is a hole fitting with a rotating shaft (not shown) at the center of the balance wheel 4, and an outer peripheral portion 2b. It is connected by the connection part 2c. In this example, a case where there are four connection portions 2c is shown. If this shape is compared to a wheel of a car, the connecting portion 2c corresponds to a spoke. Of course, the number of the connecting portions 2c can be arbitrarily determined. And the part without the connection part 2c becomes the hole 2d.

  On one surface of the outer peripheral portion 2b of the balance wheel body 2, for example, chromium (Cr) having a thickness of 1 μm is formed in a circular shape in plan view as the lower metal film 3a. Examples of the material for the lower layer metal film 3a include aluminum (Al), titanium (Ti), tungsten (W), and the like, as well as chromium having good adhesion to silicon.

  On the lower metal film 3a, for example, gold (Au) having a thickness of 200 μm is formed as the upper metal film 3b. These metal films are metals having a specific gravity larger than that of the silicon constituting the balance wheel body 2. Examples of the material for the upper metal film 3b include gold, for example, copper (Cu), nickel (Ni), lead (Pb), tin (Sn), and the like, and metal compositions thereof.

  The metal structure 3 having such a shape has a cylindrical or prismatic protrusion shape. In the example of FIG. And it can form by the technique similar to formation of the connection electrode provided in the pad of a well-known semiconductor device.

  The shape of the upper end surface of the upper metal film 3b is flat, but may be a hemispherical so-called dome shape. Such a shape of the metal structure 3 is referred to as a bump shape.

  The configuration shown in FIGS. 1B and 2B does not have the hole 2d shown in FIG. 1A, and the balance wheel body 2 uses a disk-shaped substrate. Although there is a through hole 4a that fits with a rotation shaft (not shown) at the center of the balance wheel 4, since the periphery thereof is a fitting portion 2a, the fitting portion 2a is easy to understand in FIG. This is indicated by a dotted line.

  In the balance wheel body 2 shown in FIG. 1 (b), the metal structure 3 is arranged on one surface corresponding to the outer peripheral portion 2b shown in FIG. 1 (a).

  A plurality of such metal structures 3 shown in FIGS. 1 (a) and 1 (b) are provided on a concentric circle with different distances from the through holes 4 a of the fitting portion 2 a that is the center of the balance wheel body 2. Are arranged at equal intervals. The size of the metal structure 3 in plan view can be arbitrarily determined depending on the size of the balance wheel body 2. The number of metal structures 3 provided on the balance wheel body 2 is also arbitrary. However, in order to prevent the balance wheel 4 from causing a single spindle, a well-balanced arrangement is good. For this purpose, the total number of metal structures 3 is It is preferable to be an even number.

  As shown in FIGS. 1 (a) and 1 (b), when a virtual straight line L passing through the center of the balance wheel body 2 is defined in a plan view, the plane area of the balance wheel body 2 is divided into two areas by the virtual straight line L. When divided, the total weight of the metal structures 3 in each divided region may be equal to each other.

  The metal structures 3 do not have to be arranged at equal intervals on concentric circles having different distances from the through holes 4a. For example, in the example of FIG. You may provide along.

  In the example shown in FIG. 1, the metal structure 3 is circular in plan view, but may be polygonal. At this time, it is preferable to make the line symmetric with respect to the virtual straight line L so that the balance is not easily lost.

The plurality of metal structures 3 may vary in weight.
For example, changing the volume changes the weight. In that case, for example, by changing the film thickness of the lower metal film 3a and the upper metal film 3b, the height is changed and the volume is changed. Of course, the volume may be changed by changing the size in plan view.

  For example, the weight is changed by changing the material. In that case, for example, the material of the lower metal film 3a or the upper metal film 3b or both of the metal films may be changed depending on the arrangement location of the metal structure 3. For example, the concentric metal structure 3 that is far from the through hole 4 a uses a metal having a higher specific gravity than the close metal structure 3. In this way, the moment of inertia can be further increased.

[Description of the configuration of the time governor: FIG. 3]
Here, the structure of the governor having the described balance wheel will be described with reference to FIG.
As shown in FIG. 3, the time governor 1 for a timepiece includes a balance wheel 4, a balance spring 5 that is a rotating shaft of the balance wheel 4 fitted to the balance wheel 4, and a hairspring 6 combined with the balance spring 5. The balance stem 5 is pivotally supported by the balance 7 and the main plate 8. The time governor 1 for timepieces receives the energy of the mainspring from an escapement (not shown) and regularly swings to maintain the time rate of the timepiece (the degree of advance / delay of the day) constant.

  In the example shown in FIG. 3, the balance wheel 4 is provided with the metal structure 3 on the surface of the balance wheel body 2 in the direction opposite to the direction facing the balance spring 6. With such a configuration, the clearance between the hairspring 6 and the balance wheel 4 can be reduced.

[Explanation of balance wheel adjustment: FIGS. 1, 2, and 3]
As already explained, the balance wheel 4 needs to reciprocally rotate in a regular manner. Since the balance wheel body 2 is formed by processing a silicon semiconductor substrate, it can be processed into a shape as designed, so that adjustment by processing the shape is unnecessary. However, it may be necessary to adjust the balance wheel.

  For example, when the metal structure 3 is mistakenly disposed on the balance wheel body 2 (when the metal structure 3 is displaced when the metal structure 3 is installed), a single weight may be generated. is there. Further, when the balance wheel 4 is assembled as a governor, it is necessary to adjust the moment of inertia according to the rate.

  Even in such a case, adjustment can be performed so that the balance wheel can regularly reciprocate. The method will be described below.

  The metal structure 3 functions as a weight for imparting an appropriate moment of inertia to the balance wheel 4. The balance wheel 4 is adjusted by partially removing the metal structure 3.

  As already described, the metal structure 3 is formed by the same formation technique as the connection electrode provided on the pad of the semiconductor device. For example, the metal film is formed by selectively determining the location using a mask or the like. The metal structure 3 is removed from the balance wheel body 2 by applying a rod-like structure body (for example, a tungsten needle) made of hard metal or the like from the side surface in the same manner as the known connection electrode removal method. Can be done.

  The lower metal film 3a and the upper metal film 3b constituting the metal structure 3 are in close contact with each other, but both of them can be peeled against this, so that only the lower metal film 3a may be left. it can.

By the way, how much the weight per each of the metal structures 3 provided on the balance wheel body 2 can be determined by conducting experiments and simulations in advance.
Since part or all of the metal structure 3 can be removed from the balance wheel body 2 by an adjustment operation to be described later, the total number provided in the balance wheel body 2 is determined in advance.

[Adjustment of single spindle]
The adjustment of the single spindle of the balance wheel 4 will be described.
First, the balance 5 constituting the rotating shaft body for adjustment or the speed governor shown in FIG. 3 is fitted into the through hole 4a.
Then, after holding the rotary shaft body or the balance stem 5 to be horizontally rotatable, the balance wheel 4 is slowly rotated and left.
Then, if there is a single spindle on the balance wheel 4, the balance wheel 4 stops with the heavy part at the lowest point, so the metal structure 3 closest to the lowest point is deleted.
Thereafter, the movement of the balance wheel 4 is confirmed, and this operation is repeated until the balance wheel 4 stops at any position, thereby eliminating the single spindle.

[Inertia moment adjustment]
Next, the adjustment work of the moment of inertia of the balance wheel 4 will be described.
First, a speed governor is assembled by combining the balance spring 6 with the balance wheel 4 as shown in FIG.
While experimentally measuring the rate of the watch, the magnitude of the rate to be adjusted and the number of metal structures 3 to be removed from the balance wheel 4 (ie the weight of the weight) to adjust the rate of this magnitude Know the relationship in advance.
At this time, the weight per metal structure 3 should be determined in advance.

  Then, the speed governor to be adjusted is assembled, the rate of the rate to be adjusted by measuring the rate, and the number of metal structures 3 to be removed (2n: n is an integer) corresponding to this is known. Then, one of the plurality of metal structures 3 is selected and removed.

At this time, for example, while selecting a pair of metal structures 3 that are symmetrical with respect to the center of the balance wheel 4 such as the metal structures 3A and 3A ′ shown in FIG. It is removed by the same method as in the case of adjusting the single spindle until it reaches the individual. In other words, it is removed with a good balance.
In this way, the inertia moment of the balance wheel 4 is adjusted by adjusting the rate of the watch.

[Description of the structure of the balance wheel of the second embodiment: FIGS. 4 and 5]
Next, the structure of the balance wheel in the second embodiment will be described with reference to FIGS.
4 (a) and 4 (b) are plan views of the balance wheel viewed from the same direction as FIG. FIG. 5 is a cross-sectional view taken along the imaginary straight line L (two-dot chain line) in FIGS. 4 (a) and 4 (b). A feature of the second embodiment is that the lower metal film constituting the metal structure is formed larger and the shape of the upper metal film is different.

  In the example shown in FIGS. 4A and 5, a lower metal film 13 a constituting the metal structure 13 is provided on the entire surface of the balance wheel 12 except for the through holes 14 a. An upper metal film 13b is provided in a band shape on the outer periphery of the balance wheel body 12 above the lower metal film 13a. The lower metal film 13a is made of chromium, for example, and the upper metal film 13b is made of gold, for example.

The example shown in FIGS. 4B and 5 is the same in that the lower layer metal film 13a is provided on the entire surface of the balance wheel body 12, but the upper layer provided on the outer peripheral portion of the balance wheel body 12 thereabove. The metal film 13b has a ring shape. Also in this example, the lower metal film 13a is made of, for example, chromium, and the upper metal film 13b is made of, for example, gold.

  The film thickness of chromium constituting the lower metal film 13a is, for example, 1 μm thick, and the gold film thickness of the upper metal film 13b is, for example, 300 μm thick.

  With such a configuration, the weight of the metal structure 13 can be increased. In the example shown in FIG. 4, the case where the band-shaped or ring-shaped upper layer metal film 13b is formed on one concentric circle with respect to the through hole 14a has been described. A film 13b may be provided.

  Adjustment of the half weight and the moment of inertia in the second embodiment is basically the same as in the first embodiment. The metal structure 13 can be removed by the same method. However, since the lower layer metal film 13a is on the entire surface of the balance ring body 12, the upper layer metal film 13b can be easily removed.

In that case, in the example shown in FIG. 4, while selecting a pair of metal structures 13 that are symmetrical with respect to the center of the balance wheel 14, such as the metal structures 13 </ b> B and 13 </ b> B ′ shown in FIG. 4. Remove until the desired quantity is reached.
Taking the adjustment of the moment of inertia as an example, the rate m of the watch is measured to determine the weight m of the area to be removed, and the metal structures 13B and 13B ′ are each scraped by m / 2.

  In FIG. 4, the metal structures 13B and 13B ′ are shown as dotted circles for ease of explanation, but of course, the amount to be removed is not limited to a circle. It may be removed in a rectangular shape or a band shape.

  In the second embodiment described above, the example in which the lower metal film 13a is uniformly provided on the entire surface of the balance wheel body 12 has been described, but the present invention is not limited to this. The lower metal film 13a may not be provided partially, or the lower metal film 13a may be locally thinned. The shape of the metal structure 13 may be determined in view of the size and weight of the balance wheel 14.

[Description of the structure of the balance wheel of the third embodiment: FIG. 6]
Next, the structure of the balance wheel in the third embodiment will be described with reference to FIG.
FIG. 6 is a cross-sectional view of the balance wheel viewed from the same direction as in FIGS. 2 and 5 and is an enlarged view of the metal structure portion.

  In the embodiment already described, the lower metal film and the upper metal film have the same shape, or an example in which the lower metal film is provided on the entire surface of the balance wheel, but the third embodiment has a different shape. Will be explained. As shown in FIG. 6, the metal structure 23 may have a shape that makes it easy for a rod-like structure such as a hard metal to be caught when the metal structure 23 is removed.

  For example, as shown in FIG. 6A, the upper metal film 23b may be formed to be slightly larger than the lower metal film 23a so as to have a so-called mushroom shape. If it does in this way, a rod-shaped structure will be caught in the constriction part 23c, and it will become easy to remove the metal structure 23. FIG.

  Further, as shown in FIG. 6B, a groove 24 may be formed on the upper end surface or side surface of the metal structure. If it does in this way, a rod-shaped structure will be caught in the groove | channel 24, and it will become easy to remove the metal structure 23. FIG.

  Of course, the thickness of the lower layer metal film and the upper layer metal film constituting the metal structure in the embodiment described above is not limited to the exemplified numerical values, but the lower layer metal film and the upper layer metal film are Of course, other materials from the examples used in the description can also be used. Further, these two metal films may have a laminated structure of different metal films. For example, the lower metal film may be a laminated film of titanium and tungsten, and the upper metal film may be a laminated film of gold and platinum (Pt).

  Further, in the embodiment of the present invention described above, the example in which the metal structure comes to the lower surface of the balance wheel body when the balance wheel is placed on the governor has been described, but this is directed to the upper surface of the balance wheel body. You may do it. In that case, it goes without saying that the clearance from the balance spring is made as specified.

  Of course, the metal structure may be provided on both sides of the balance wheel. In that case, one surface may be configured as shown in FIG. 1, and the other surface may be configured as shown in FIG. Of course, the arrangement form may be changed for each surface in consideration of easy removal when the metal structure is removed for adjustment. In such a case, it may be determined in view of the size and weight of the balance wheel.

  According to the present invention, even if a silicon balance wheel, which is a brittle material, is used, the half weight and the moment of inertia can be adjusted. Therefore, it is suitable as a speed governor for a small and light wristwatch.

DESCRIPTION OF SYMBOLS 1 Timepiece for timepieces 2, 12 Balance wheel body 2a Fitting part 2b Outer peripheral part 2c Connection part 3, 13, 23 Metal structure 3a, 13a, 23a Lower layer metal film (for example, chromium)
3b, 13b, 23b Upper metal film (for example, gold)
4, 14 Balance wheel 4a, 14a Through hole 5 Balance 6 Balance spring 7 Balance holder 8 Ground plate 23c Constricted portion 24 Groove

Claims (7)

  A balance wheel that fits and cooperates with a rotating shaft that constitutes a time governor for a watch, and has a fitting portion that fits on the rotating shaft and an outer peripheral portion, and is composed mainly of silicon. A metal structure is provided on a plane of the substrate that is formed of a substrate and is orthogonal to the axial direction of the rotation axis, and the metal structure is in close contact with the lower metal film and the lower metal film that are in close contact with the substrate, and different materials. A balance wheel characterized by being laminated with an upper metal film.   The balance wheel according to claim 1, wherein the lower metal film and the upper metal film are made of a metal having a specific gravity greater than that of the substrate.   The balance wheel according to claim 1, wherein the metal structure has a bump shape.   The balance wheel according to claim 1, wherein the metal structure has a band shape.   The balance wheel according to claim 4, wherein the metal structure has a ring shape in which the rotation shaft is a concentric circle.   The balance wheel according to any one of claims 1 to 5, wherein the lower metal film is provided on the entire surface of the plane. When a virtual straight line passing through the center of the rotation axis is drawn in parallel to the plane, and the area of the plane is divided, the weight of the metal structure in the divided area is the same between the areas. The balance wheel according to any one of claims 1 to 6.

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