JP2017049081A - Hairspring and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hairspring that in a speed control mechanism of a mechanical timepiece, even when a silicon-based hairspring is employed, is strong in shock, and a manufacturing method therefor.SOLUTION: A hairspring 1 includes: a collet 3 having an open hole 3a to be fitted to a rotational shaft body; a coil-shaped spring part 2 connected to the collet 3, and wound around the collet 3 with the open hole 3a as a center; and a stud 4 for fixing an outer end of the spring part 2 to a balance holder, wherein at an outermost side curve part or on at least one plane of the spring part 2 except for a connection part between itself and the collet 3, a groove part 7 is provided, and at the groove part 7 and on a hairspring surface, a resin layer 6 is provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hairspring for a watch and a method for manufacturing the same.

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

  The balance is connected to a mechanism called an escapement consisting of a escape wheel and an ankle, and energy is transmitted from the mainspring so that the balance keeps vibrating.

  Known balance springs are often formed by processing metal. For this reason, the shape as designed may not be obtained due to variations in processing accuracy or the influence of internal stress of the metal.

  Since the balance spring needs to maintain the isochronism by regularly vibrating the balance with the balance spring, if the balance spring cannot obtain the shape as designed, the balance wheel will not be able to move isochronously and the rate of the watch Deviation occurs. The rate of the watch indicates the degree of advance or delay of the watch per day.

  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.

  According to this technology, since the etching does not go under the part masked with photoresist, the mask pattern can be faithfully reproduced in the vertical depth direction, and the watch part is designed when etching the silicon substrate. It has become possible to manufacture accurately with the street shape.

  In the first place, silicon has better temperature characteristics than metal. It has a feature that it is less likely to be deformed with respect to ambient temperature than a metal used as a material for a conventional hairspring. For this reason, it is considered to apply this technique to a speed control mechanism of a timepiece.

  However, a silicon hairspring that takes these points into consideration is already known (see, for example, Patent Document 1).

  In the prior art shown in Patent Document 1, in order to obtain good isochronism, the thickness of the outer curved portion of the silicon balance spring is made thicker than other windings to increase the rigidity of the outer curved portion. is there.

Japanese Patent No. 5389999 (2nd page, FIG. 6)

  However, it has been found that the prior art disclosed in Patent Document 1 cannot sufficiently prevent the hairspring from being damaged when a large impact is applied to the timepiece. In other words, when the thickness of the outer curved portion is increased, the distance between the adjacent windings becomes narrower, so that the hairsprings easily come into contact with each other, and the hairspring may be damaged by the impact.

  When the hairspring is broken, the fragments may scatter and enter the timepiece mechanism, which not only stops the hairspring from moving, but also may cause a fatal failure to the timepiece itself.

  SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the object of the present invention is to provide a balance spring that is resistant to impact and has good isochronism even if a silicon balance spring is employed in a speed adjusting mechanism of a mechanical timepiece, and a method for manufacturing the same. Is to provide.

  The hairspring in the present invention for achieving the above-described object employs the following configuration.

  The hairspring of the present invention is a whisker having a through hole for fitting with a rotating shaft, a coil-shaped mainspring part connected to the whistle and wound around the whisker around the through hole, A mainspring having a hairspring for fixing the outer end of the mainspring portion to the balance holder, and having a groove portion on at least one plane of the mainspring portion excluding the outermost curved portion or the connection portion with the hairball. A resin layer is provided on the groove portion and the hairspring surface.

  As a result, when the timepiece is subjected to a large impact, the groove and the resin layer on the surface of the hairspring serve to prevent the hairspring from being damaged, and at the same time, the timepiece has good isochronism.

  The hairspring is preferably silicon.

  In this way, since the silicon is relatively light, a lightweight hairspring can be formed.

  The resin layer is preferably a paraxylylene resin.

  If it does in this way, since a resin layer is comparatively soft, it will become easy to absorb an impact.

  Moreover, you may make it the groove part penetrate from the one plane of the mainspring part to the other plane facing this.

  If it does in this way, the volume of a resin layer can be increased and the range which can adjust the characteristic of a hairspring will spread.

A hairspring in the present invention for achieving the above-described object employs the following manufacturing method.

The method of manufacturing the hairspring of the present invention includes a ball having a through hole for fitting with a rotating shaft body, a coil-shaped spring that is connected to the ball and wound around the ball around the through hole. And a hairspring having a hairpin for fixing the outer end of the mainspring portion to the balance holder, except for a portion of the mainspring portion that becomes a connection portion with the outermost curved portion or the hairball. A step of forming a groove on the substrate, an etching step of etching the substrate to form a hairspring having a shape having a groove on the mainspring portion, and a step of forming a resin layer on the surface of the groove and the mainspring. Features.

  According to such a manufacturing method, it is possible to easily manufacture a hairspring in which a resin layer is provided on the groove and the surface.

  Since the mainspring portion constituting the hairspring is tough, even if the watch is subjected to a strong impact, the hairspring becomes difficult to break, and at the same time the isochronism of the watch is improved.

It is the top view and sectional drawing explaining the structure of the hairspring in the 1st Embodiment of this invention. FIG. 3 is a cross-sectional view showing a method for manufacturing a hairspring in the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a method for manufacturing a hairspring in the first embodiment of the present invention. It is sectional drawing explaining the structure of the hairspring which is the 2nd and 3rd embodiment of this invention. It is a top view of the balance spring of a prior art, and is a simulation image explaining a problem.

  The hairspring of the present invention comprises a coil-shaped mainspring portion wound around a whisker ball made of a first material, and a groove portion is provided on one plane of the mainspring portion excluding the outermost curved portion connected to the whiskers 4. A resin layer of a second material having higher toughness than the first material is provided in the groove.

  Viscosity refers to the property of being hard to break against external pressure, tenacity. By providing a resin layer with high toughness in the groove of the mainspring portion, the brittleness of the mainspring portion is reduced and the mainspring portion can be strengthened.

  Hereinafter, the hairspring of the present invention will be described in detail with reference to the drawings. First, as a first embodiment, a schematic configuration of the hairspring of the present invention will be described with reference to FIG. 1, and then a further detailed configuration of the mainspring portion will be described with reference to FIG.

[First Embodiment]
[Description of the structure of the hairspring: FIG. 1]
A first embodiment of the hairspring will be described in detail with reference to FIG. Fig.1 (a) has shown the state of the hairspring before forming a resin layer, and shows a mode when planarly viewing the hairspring 1 from the axial direction of the rotating shaft body which is not shown in figure. An actual hairspring has a larger number of windings, but here, only four windings are shown in a simplified manner.

  In FIG. 1 (a), a hairspring 1 includes a whisker ball 3 having a through hole 3a for fitting with a spring which is a rotating shaft body (not shown) at the center, and a whisker ball 3 centering on the through hole 3a. The coil-shaped mainspring 2 is designed to be wound around the mainspring 2, and the whiskers 4 are connected to the winding end of the mainspring 2. The winding start of the mainspring portion 2 and the whistle ball 3 are connected by a connecting portion 3b.

  The first material of the hairspring 1 can be made of a material mainly composed of quartz, ceramics, silicon, silicon oxide film, or the like. If the first material is silicon, a light hairspring can be constructed, which is convenient. In the following description, the case where the first material is silicon that is light and easy to process will be described as an example.

  Assuming that the first material constituting the hairspring 1 is silicon, the manufacturing and processing of the hairspring 1 can use the deep RIE technique performed on the silicon semiconductor substrate, and the manufacturing of the semiconductor device. Similar known manufacturing techniques can be used.

  FIG. 1B is a view after the resin layer 6 is formed, and is an enlarged view of the mainspring portion 2 shown in FIG. 1A, and is a cross-sectional view taken along the line AA ′ shown in FIG. It is sectional drawing which shows a mode typically. The mainspring portion 2 is integrally formed, and has a shape that is wound around the hair ball 3. In FIG.1 (b), four parts of the mainspring part 2 are expanded and shown. The mainspring portion 2 is a single structure, and description will be given by giving the names of the mainspring arms 20a, 20b, 20c, and 20d to the four portions included in the AA ′ cross section of FIG.

  The groove portion 7 is not formed in the mainspring arm 20d of the outermost curved portion connected to the whiskers 4 and the mainspring arm (not shown in FIG. 1B) of the connection portion 3b of the beard ball 3, and the inner side thereof. A groove portion 7 is provided on a flat surface 2a of the winding mainspring arms 20a, 20b, and 20c. As described above, since the mainspring arms 20a to 20d are an integral structure, the groove portion 7 and the resin layer 6 are also one structure. A paraxylylene-based resin known as Parylene (registered trademark), which is a resin having lower rigidity than silicon, is formed as a resin layer 6 of the second material on the surface of the hairspring 1 and in the groove portion 7. The second material is a material having higher toughness than the first material.

  Although not particularly limited, for example, one mainspring arm has a width e of 60 μm and a height h of 100 μm. Thus, even if the mainspring arm is thin in the width direction, the mainspring portion 2 can be made brittle and toughened by forming the resin layer 6 in the groove portion 7 and on the surface of the mainspring arms 20a to 20d.

[Description of Effects of First Embodiment]
Although the winding width e and height h are the same regardless of the presence or absence of the groove portion 7, the paraxylene resin has lower rigidity than silicon, and therefore the mainspring arm 20 a in which the resin layer 6 is formed in the groove portion 7. The mainspring arm 20d of the outermost curved portion without the groove portion 7 and the mainspring arm of the connecting portion 3b of the beard ball 3 can be made more rigid than .about.20c. Further, since it is not necessary to increase the width e of the mainspring arm 20d of the outermost curved portion, there is little risk of contact with the adjacent winding, and damage to the mainspring 1 can be prevented. Furthermore, since the resin layer 6 with low rigidity (soft) is formed on the entire surface of the mainspring portion 2, even if it comes into contact, the risk of breakage is further reduced. Further, if the first material is silicon, a light hairspring can be constructed, which is convenient.

  For the hairspring formed as described above, when a model of the hairspring was created on the simulation software and a motion analysis was attempted, it was found that the stiffness of the hairspring affected the vibration characteristics. FIG. 5 is a simulation image showing the behavior of the hairspring. FIG. 5 (a) is an example of a model in which the hairspring is made uniform without providing the groove portion 7, and eccentricity occurs during vibration expansion and contraction (the through hole of the beard ball is not at the center of the entire hairspring). ). FIG. 5B is an example of the model of the mainspring 1 of the present invention in which the rigidity of the outermost curved portion is increased. In this case, no eccentricity is generated during the expansion and contraction motion of the vibration (the through hole of the beard ball has a hairspring). In the center of the whole).

As shown in FIG. 5A, if eccentricity occurs during the expansion and contraction movement, the time accuracy of the timepiece is deteriorated, and isochronism is deteriorated. On the other hand, as shown in FIG. 5B, when the rigidity is increased without forming a groove in the outermost curved portion, eccentricity does not occur during the telescopic movement, and the isochronism of the timepiece becomes very good.

  Furthermore, if the movement becomes eccentric when the hairspring 1 is operated, a portion where the interval between the mainspring arms is locally narrowed and the possibility of coming into contact with the adjacent mainspring arm is increased, the model of the present invention. If the movement is concentric like this, the risk of contact with the adjacent mainspring arm is reduced.

  When the hairspring 1 of the present invention was actually operated and the telescopic motion was photographed with a high-speed camera and confirmed, no eccentric motion was observed, and it was confirmed that the motion was concentric.

[Description of Manufacturing Method of First Embodiment: FIGS. 2 to 3]
Next, the manufacturing method of the hairspring 1 which is the 1st Embodiment of this invention is demonstrated using FIG.2 and FIG.3.

  First, the shape of the hairspring 1 having the groove portion 7 is formed, and the resin layer 6 is formed on the surface and groove portion of the hairspring in the next step.

  First, as shown in FIG. 2A, a silicon substrate 200 having at least an area and a thickness that allow the hairspring 1 to be taken out is prepared. If the productivity of the hairspring 1 is taken into consideration, it is preferable that the substrate 200 has a size that allows a large number of hairsprings 1 to be taken out.

  Next, as shown in FIG. 2B, a mask 8 having an opening corresponding to the groove portion 7 is known in order to form the groove portion 7 in the mainspring portion 2 of the hairspring 1 on the substrate 200. It is formed by photolithography technology. The mask 8 is a silicon oxide film, for example. Although not particularly limited, the mask 8 is formed with a film thickness of 1 μm.

Then, by using the mixed gas (SF ₆ + C ₄ F ₈ ) while managing the processing time, the substrate 200 is dry-etched by the RIE technique, and as shown in FIG. 1A, the mainspring portion of the hairspring 1 2, the beard ball 3, and the whiskers 4 are integrally formed. A groove 7 having a predetermined width and depth is formed in the mainspring 2.

  Thereafter, only the mask 8 is removed to obtain the substrate 200 shown in FIG. The removal of the mask 8 is performed, for example, by immersing the substrate 200 in a known etching solution mainly containing hydrofluoric acid.

  Next, as shown in FIG. 2D, the mask 9 is known so as to cover a portion (groove portion is covered) corresponding to the width of the mainspring arms 20a to 20d, which becomes the mainspring portion 2 of the substrate 200. It is formed by photolithography technology. As described above, the mask 9 has a shape that forms the entire hairspring 1 although not shown. The mask 9 is, for example, a silicon oxide film. Although not particularly limited, the mask 9 is formed to have a thickness of 2 μm from the surface of the substrate 200.

After that, using the mixed gas (SF ₆ + C ₄ F ₈ ), the substrate 200 is deeply etched and dry-etched by the RIE technique. Thereby, the mainspring arms 20a to 20d are separated from the substrate 200 as shown in FIG. In this state, although not shown, the hairspring 1 is cut out independently from the substrate 200, and the through-hole 3 a of the whistle ball 3 also penetrates.

Thereafter, only the mask 9 is removed to obtain the shape of the hairspring 1 provided with the groove 7 made of silicon, as shown in FIG. The removal of the mask 9 is performed, for example, by immersing the substrate 200 in a known etching solution mainly containing hydrofluoric acid.

  Next, a method for forming the resin layer 6 on the hairspring 1 will be described. After forming the hairspring 1 provided with the groove 7, the surface of the hairspring 1 and the groove 7 are simultaneously controlled by controlling the processing time by a thin film formation process of a vapor deposition polymerization method which is a known film forming technique. A resin layer 6 of paraxylylene resin is formed.

  Since the paraxylylene resin film formed by the vapor deposition polymerization method has good throwing power, it is formed with a uniform thickness over the entire surface of the hairspring 1 and is also formed inside the groove portion 7. At this time, the thickness of the thin film (resin layer 6) is increased and the groove portion 7 is filled. However, when the resin layer 6 is thin in relation to the size of the groove portion 7, as shown in FIG. Although the inside of 7 is not filled with the resin layer 6, when the resin layer 6 becomes thick, the groove portion 7 is filled with the resin layer 6 as shown in FIG.

  The resin layer 6 made of a paraxylylene-based resin film is a very stable material with little change over time, and thus has high reliability without changing the toughness even when used for a long time.

[Description of Effects of Manufacturing Method of First Embodiment]
As described above, assuming that the first material constituting the hairspring 1 is silicon, the deep RIE technique performed on the silicon semiconductor substrate can be used for manufacturing and processing the hairspring 1, and the semiconductor device This is convenient because a known manufacturing technique similar to that for manufacturing can be used. Further, when the resin layer 6 as the second material is formed on the surface of the mainspring portion 2 and the groove portion 7, it is convenient because it can be simultaneously processed by using a known CVD technique.

[Second Embodiment]
[Description of Mainspring Configuration in Second Embodiment: FIG. 4 (a)]
Next, a configuration example having a different shape from the hairspring 1 of the first embodiment will be described as a second embodiment with reference to FIG. In the description, a single mainspring arm will be described as an example.

  As described above, the mainspring arm is one continuous structure. For example, as shown in FIG. 4A, the mainspring arm 21a of the mainspring portion 2 is provided with a groove portion 17a on one plane 2a thereof. The groove portion 17b is also provided on the other plane 2b facing this one plane. Resin layers 16 are formed on the surfaces of the grooves 17a and 17b and the mainspring arm 21a, respectively. That is, the difference between the hairspring 1 in the first embodiment and the hairspring 11 in the second embodiment is that the hairspring 1 is provided with the groove portion 7 only on one plane 2a, whereas the hairspring 11 has two differences. That is, the grooves 17a and 17b are provided in both of the two planes 2a and 2b.

[Third Embodiment]
[Description of the configuration of the mainspring in the third embodiment: FIG. 4B]
Next, a further different configuration example of the hairspring 1 from the first embodiment and the shape of the heel will be described as a third embodiment with reference to FIG. As shown in FIG.4 (b), you may provide the groove part 27a so that the mainspring arm 22a may be penetrated. In other words, the mainspring arm 22a of the mainspring portion 2 is provided with a groove portion 27a penetrating the other flat surface 2b opposite to the one flat surface 2a. A resin layer 26 is formed on the surfaces of the groove 27a and the mainspring arm 22a. That is, the difference between the hairspring 1 in the first embodiment and the hairspring 21 in the third embodiment is that the hairspring 1 is provided with the groove portion 7 only in one plane 2a, whereas in the hairspring 21, the hairspring is different. That is, a groove portion 27a penetrating the arm 22a is provided. The materials of the hairspring 1 and the resin layer 26 are the same as those in the first embodiment.

[Description of Effects of Second and Third Embodiments]
If the configuration of the second embodiment and the third embodiment is used as described above, the characteristic of the hairspring 1 is not obtained simply by providing the groove portion 7 on one plane of the mainspring portion 2 as in the first embodiment. When sufficient, the ratio of the volume of the resin layer 16 or 26 to the mainspring arm 21a or 22a of the hairspring 11 or 21 having a constant cross-sectional area can be increased, and the range in which the characteristics of the hairspring can be adjusted. Is convenient to spread.

  In any of the embodiments, the example in which the groove portion is not formed in both the mainspring arm of the outermost curved portion and the mainspring arm of the connection portion with the whisker ball is shown, but the present invention is not limited to this. The groove portion may not be formed only in the mainspring arm of the outermost curved portion, and the groove portion may not be formed only in the mainspring arm of the connection portion with the whiskers. In either case, the same effect can be obtained.

  Since the strength of the hairspring can be improved, the present invention is particularly effective in a portable device such as a wristwatch because an unexpected impact is applied. In the present embodiment, the description has been given with respect to the silicon hairspring. However, the present invention is not limited to this, and the present invention is also effective in a ceramic or metal hairspring.

DESCRIPTION OF SYMBOLS 1, 11, 21 Hairspring 2 Spring main part 20a, 20b, 20c, 20d, 21a, 22a Mainspring arm 2a One plane 2b Plane 3 Beard ball 3a Through-hole 3b Connection part 4 Beard 6, 16, 26 Resin layer 7, 17a 17b, 27a Groove 8, 9 Mask 200 Silicon substrate

Claims (5)

A hair ball having a through hole for fitting with a rotating shaft body, a coil-shaped mainspring portion connected to the whisker ball and wound around the hair ball around the through hole, and A hairspring having a whisker for fixing the outer end to the balance holder,
A hairspring having a groove portion on at least one plane of the mainspring portion excluding an outermost curved portion or a connecting portion with a hairball, and a resin layer is provided on the groove portion and the surface of the hairspring.   The hairspring according to claim 1, wherein the hairspring is silicon.   The hairspring according to claim 1 or 2, wherein the resin layer is a paraxylylene resin.   The hairspring according to any one of claims 1 to 3, wherein the groove portion penetrates from the one plane of the mainspring portion to the other plane facing the mainspring portion. A hair ball having a through hole for fitting with a rotating shaft body, a coil-shaped mainspring portion connected to the whisker ball and wound around the hair ball around the through hole, and A method of manufacturing a hairspring having a whisker for fixing an outer end to a balance holder,
The step of forming a groove in the substrate, except for the location of the mainspring portion, which is the outermost curved portion or the connecting portion with the ball,
Etching the substrate and forming a mainspring having a shape having the groove in the mainspring portion; and
And a step of forming a resin layer on the groove and the surface of the hairspring.

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