JP2014163784A - Temperature-compensated balance, timepiece movement, and mechanical timepiece - Google Patents

Abstract

A temperature-compensated balance with a sufficient strength and a temperature correction amount for a required moment of inertia, and a timepiece movement and a mechanical timepiece having the temperature-compensated balance.
And a plurality of bimetal portions arranged in a circumferential direction around the pivot shaft of the stem and extending in an arc shape along the circumferential direction of the pivot shaft; A balance wheel having a connecting member for connecting the plurality of bimetal portions 50 and the balance stem in the radial direction, and the bimetal portion 50 includes a first member 60 and a second member 61 having different thermal expansion coefficients in the radial direction. The laminated body is overlapped, and one end in the circumferential direction is a fixed end 50A connected to the connecting member, the other end in the circumferential direction is a free end 50B, and the bimetal portion 50 is a free end from the fixed end 50A side. The thickness along the radial direction is gradually reduced toward the 50B side.
[Selection] Figure 6

Description

  The present invention relates to a temperature-compensated balance, a timepiece movement, and a mechanical timepiece.

The governor of a mechanical timepiece is generally composed of a balance with a balance and a hairspring. Of these, the balance with a balance and a balance wheel fixed to the balance is a member that periodically vibrates and vibrates around the rotation axis of the balance. At this time, it is important that the vibration cycle of the balance with hairspring is set within a predetermined value. This is because if the vibration period deviates from the specified value, the rate of the mechanical timepiece (timepiece delay, degree of advancement) changes. However, the vibration period of the balance with hairspring is easily changed due to various causes, for example, it is also changed due to a temperature change.
Here, the vibration period T is expressed by the following equation (1).

In the above formula (1), I represents “the moment of inertia of the balance”, and K represents “the spring constant of the hairspring”. Therefore, when the moment of inertia of the balance or the spring constant of the hairspring changes, the vibration period also changes.
Here, the metal material used for the balance with hairspring is generally a material having a positive coefficient of linear expansion, and expands as the temperature rises. As a result, the balance wheel expands in diameter and increases the moment of inertia. Moreover, since the Young's modulus of the steel material generally used for the hairspring has a negative temperature coefficient, the spring constant is lowered by the temperature rise.

  As described above, when the temperature rises, the moment of inertia increases and the spring constant of the mainspring decreases. Therefore, as apparent from the above formula (1), the vibration period of the balance with hairspring becomes a characteristic that is short at a low temperature and long at a high temperature. For this reason, the time characteristic of the timepiece is such that it proceeds at a low temperature and is delayed at a high temperature.

Therefore, as a measure for improving the temperature characteristic of the vibration frequency of the balance with the balance, a part of the rim constituting the balance wheel has one end in the circumferential direction as a fixed end and the other end in the circumferential direction as a free end. A method using a bimetal obtained by joining metal plates made of materials having different coefficients of thermal expansion in the radial direction is known (see Non-Patent Document 1).
Among the above-described bimetals, for example, a low thermal expansion material such as Invar is used as the material of the metal plate located on the radially inner side, and a high thermal expansion material such as brass is used as the material of the metal plate located on the radially outer side. By doing so, when the temperature rises, the bimetal deforms inward so that the free end side moves inward in the radial direction due to the difference in thermal expansion coefficient. As a result, the average diameter of the rim portion can be reduced to reduce the moment of inertia, and the temperature characteristic of the moment of inertia can have a negative slope. As a result, the temperature dependency of the vibration period of the balance with hairspring can be kept low.

Swiss College of Watchmaking, “The Theory of History”, English version, 2nd edition, April 2003, p136-137

However, in the above-described method, since the other end portion in the circumferential direction of the rim portion is a free end, the rim portion may be plastically deformed or damaged due to an impact or the like when using the timepiece. As a result, the balance of the balance with the balance or the moment of inertia changes, resulting in a deviation in the rate, which may reduce the timing accuracy.
In particular, a balance with a balance may have a weight part such as a chiller screw attached to the rim part in order to increase the temperature correction amount of the moment of inertia (the amount of change in the radial direction of the rim part). The risk of damage and the like becomes more prominent.

  On the other hand, it is conceivable to increase the thickness of the rim portion along the radial direction to improve the strength of the rim portion, but the amount of deformation of the bimetal is inversely proportional to the plate thickness. There is a problem that the amount of deformation of the bimetal is reduced, and the necessary temperature correction amount of the moment of inertia cannot be secured.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a temperature-compensated balance that can secure a temperature correction amount of a necessary moment of inertia while securing strength, and a timepiece including the same. Movement and mechanical watch.

The present invention provides the following means in order to solve the above problems.
(1) The temperature-compensated balance according to the present invention is arranged with the balance rotating around the shaft center and the circumferential direction around the rotation shaft of the balance, and along the circumferential direction of the rotation shaft. A plurality of bimetal portions extending in an arc shape, and a balance wheel having a connecting member for connecting the plurality of bimetal portions and the balance stem in the radial direction, wherein the bimetal portions have different coefficients of thermal expansion. A laminated body in which the member and the second member are overlapped in the radial direction, one end in the circumferential direction is a fixed end connected to the connecting member, the other end in the circumferential direction is a free end, and the bimetal portion is The thickness along the radial direction gradually decreases from the fixed end side toward the free end side.

  According to this configuration, when a temperature change occurs, the bimetal portion bends and deforms in the radial direction from the fixed end due to the difference in thermal expansion coefficient between the first member and the second member. It can be moved inward or outward in the direction. Thereby, the position of the free end of a bimetal part can be changed to radial direction. Therefore, the average diameter of the balance wheel can be reduced or expanded, and the moment of inertia of the entire balance of the balance can be changed by changing the distance from the rotation axis of the balance. Thereby, the inclination of the temperature characteristic of the moment of inertia can be changed, and temperature correction can be performed.

Here, since the thickness along the radial direction of the bimetal portion is gradually reduced from the fixed end side toward the free end side, the bimetal portion is easily bent and deformed from the fixed end side toward the free end side. Specifically, the bimetal portion is deformed so as to be inclined in the radial direction toward the free end side. Therefore, the amount of change along the radial direction on the free end side of the bimetal portion (hereinafter simply referred to as radius change amount) is larger than the radius change amount on the fixed end side. Therefore, the amount of change in radius on the free end side can be increased while maintaining the thickness on the fixed end side, so that a necessary temperature correction amount for the moment of inertia can be ensured while ensuring the strength.
As a result, plastic deformation and damage of the bimetal part due to impact etc. can be suppressed, temperature correction work can be performed stably as intended, the rate does not change easily due to temperature change, and high quality with excellent temperature compensation performance Can be a tempura.

(2) In the temperature-compensated balance according to the present invention, the first member is disposed radially inward of the second member, and is integrally formed with the connecting member by a ceramic material. And among the said 2nd member, the thickness in alignment with the radial direction in the said 1st member may become gradually thin as it goes to the said free end side from the said fixed end side.
According to this configuration, the balance can be created using a semiconductor process such as a photolithography technique by forming the connecting member and the first member from a ceramic material such as silicon. In this case, it is possible to provide a balance with high accuracy and high accuracy compared with the case where the connecting member and the first member are created by machining or the like. Moreover, since it can form simply and efficiently, it is easy to improve and improve manufacturing efficiency.
And, in the case where the first member is formed of a ceramic material which is a brittle material by forming at least the first member gradually thinner from the fixed end side toward the free end side among the first member and the second member. Even if it exists, after ensuring intensity | strength in the fixed end side, the amount of radius changes can be ensured.

(3) In the temperature compensated balance according to the present invention, the thickness ratio of the first member and the second member in the radial direction may be constant from the fixed end side to the free end side.
According to this configuration, the degree of deformation of the first member and the second member is constant from the fixed end side to the free end side based on the thermal expansion coefficient and Young's modulus. In other words, since the variation in the degree of deformation due to the difference in thickness ratio can be suppressed, the bimetal portion can be stably deformed, and the length along the circumferential direction of the bimetal portion according to the temperature correction amount of the required moment of inertia. It becomes easy to set the size.

(4) In the temperature compensation type balance according to the present invention, a weight portion may be provided at the free end of the bimetal portion.
According to this configuration, since the weight of the free end of the bimetal portion can be increased by the weight portion, the temperature of the moment of inertia can be more effectively corrected with respect to the amount of radius change at the free end. Therefore, it is easy to improve the temperature compensation performance.

(5) In the timepiece movement according to the present invention, a barrel wheel having a power source, a train wheel for transmitting the rotational force of the barrel wheel, an escapement mechanism for controlling the rotation of the train wheel, and the escapement mechanism The temperature compensated balance of the present invention may be provided.
According to this configuration, since the temperature compensation balance with high temperature compensation performance is provided as described above, it is possible to obtain a high-quality timepiece movement with less error in yield.

(6) The mechanical timepiece according to the present invention may include the timepiece movement according to the present invention.
According to this configuration, since the timepiece movement described above is provided, a high-quality mechanical timepiece with less error in rate can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring intensity | strength, the temperature compensation type balance which can ensure the temperature correction amount of a moment of inertia, the movement for timepieces provided with this, and a mechanical timepiece can be provided.

It is a figure which shows embodiment which concerns on this invention, Comprising: It is a block diagram of the movement of a mechanical timepiece. It is a perspective view of the balance (temperature compensation type balance) which comprises the movement shown in FIG. It is AA sectional drawing shown in FIG. It is a top view of the balance wheel which comprises the balance shown in FIG. It is BB sectional drawing shown in FIG. It is an enlarged plan view of a bimetal part. FIG. 5 is a process diagram when the balance wheel shown in FIG. 4 is manufactured, and is a cross-sectional view showing a state in which a silicon oxide film is formed on a silicon substrate. It is sectional drawing which shows the state which formed the circular-arc-shaped groove part in the silicon oxide film from the state shown in FIG. It is a perspective view of the state shown in FIG. It is sectional drawing which shows the state which formed the resist pattern on the silicon oxide film from the state shown in FIG. It is a perspective view of the state shown in FIG. It is a top view of the state shown in FIG. It is sectional drawing which shows the state which removed the silicon oxide film selectively from the state shown in FIG. 10 using a resist pattern as a mask. It is a perspective view of the state shown in FIG. It is sectional drawing which shows the state which removed the silicon substrate selectively from the state shown in FIG. 13 by using a resist pattern and a silicon oxide film as a mask. It is a perspective view of the state shown in FIG. It is sectional drawing which shows the state which removed the resist pattern from the state shown in FIG. 15, and formed the precursor. It is a perspective view of the state shown in FIG. FIG. 18 is a cross-sectional view illustrating a state in which the precursor illustrated in FIG. 17 is reversed and then bonded to the adhesive layer of the first support substrate. It is a perspective view of the state shown in FIG. FIG. 20 is a cross-sectional view showing a state in which the second member is formed by growing gold by electroforming in the precursor electroforming open space from the state shown in FIG. 19. It is a perspective view of the state shown in FIG. FIG. 22 is a cross-sectional view showing a state in which the precursor is removed from the first support substrate and reversed again from the state shown in FIG. 21, and then bonded to the adhesive layer of the second support substrate. It is sectional drawing which shows the state which removed the guide wall for electroforming from the state shown in FIG. It is a perspective view which shows the state which removed the 2nd support substrate from the state shown in FIG. FIG. 26 is a cross-sectional view showing a state where the silicon oxide film is removed from the state shown in FIG. 25. It is a perspective view of the state shown in FIG. It is a graph which shows radius change amount (DELTA) R (mm) with respect to circular arc angle (theta) (deg) in a bimetal part.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
[Configuration of mechanical watch, watch movement, temperature compensation balance]
As shown in FIG. 1, the mechanical timepiece 1 of the present embodiment is, for example, a wristwatch, and includes a movement (timepiece movement) 10 and a casing (not shown) that houses the movement 10.

(Composition of movement)
This movement 10 has a base plate 11 constituting a substrate. A dial (not shown) is arranged on the back side of the main plate 11. A train wheel incorporated on the front side of the movement 10 is referred to as a front train wheel 28, and a train wheel incorporated on the back side of the movement 10 is referred to as a back train wheel.
A winding stem guide hole 11a is formed in the base plate 11, and a winding stem 12 is rotatably incorporated therein. The winding stem 12 is positioned in the axial direction by a switching device having a setting lever 13, a yoke 14, a yoke spring 15 and a back presser 16. In addition, a chichi wheel 17 is rotatably provided on the guide shaft portion of the winding stem 12.

  Under such a configuration, the winding stem 12 is rotated in a state where the winding stem 12 is at the first winding stem position (0th stage) closest to the inside of the movement 10 along the rotation axis direction, for example. As a result, the chisel wheel 17 rotates through the rotation of the pinion wheel (not shown). And when this chi-wheel 17 rotates, the round hole wheel 20 which meshes with this rotates. And when this round hole wheel 20 rotates, the square wheel 21 which meshes with this rotates. Further, when the square hole wheel 21 rotates, the mainspring (power source) (not shown) housed in the barrel complete 22 is wound up.

  The front wheel train 28 of the movement 10 includes a second wheel 25, a third wheel 26 and a fourth wheel 27 in addition to the barrel wheel 22, and has a function of transmitting the rotational force of the barrel wheel 22. . Further, an escapement mechanism 30 and a speed control mechanism 31 for controlling the rotation of the front train wheel 28 are disposed on the front side of the movement 10.

The center wheel 25 is a gear that meshes with the barrel complete 22. The third wheel 26 is a gear that meshes with the second wheel 25. The fourth wheel 27 is a gear that meshes with the third wheel 26.
The escapement mechanism 30 is a mechanism that controls the rotation of the front wheel train 28 described above, and an escape wheel 35 that meshes with the fourth wheel 27 and an ankle that moves the escape wheel 35 and rotates it regularly. 36.
The speed regulating mechanism 31 is a mechanism for regulating the escapement mechanism 30, and includes a balance (temperature compensated balance) 40.

(Structure of balance)
As shown in FIGS. 2 and 3, the balance with hairspring 40 rotates around an axis (rotation axis) O (rotates about the axis) and a balance wheel 42 attached to the balance 41. And a balance spring (spring spring) 43, and is a member that is rotated forward and backward around the axis O with a constant vibration cycle by the power transmitted from the balance spring 43.
In the present embodiment, a direction orthogonal to the axis O is referred to as a radial direction, and a direction around the axis O is referred to as a circumferential direction.

  The balance stem 41 is a rotating shaft body that extends vertically along the axis O, and the upper end portion and the lower end portion thereof are pivotally supported by members (not shown) such as a base plate and a balance holder that constitute the above-described movement 10. A substantially intermediate portion in the vertical direction of the balance stem 41 is a large diameter portion 41a having the largest diameter. Further, in the balance stem 41, a cylindrical swing seat 45 is externally provided coaxially with the axis O at a portion located below the large diameter portion 41a. The swing seat 45 has an annular flange 45a projecting outward in the radial direction, and a swing stone 46 for swinging the ankle 36 is fixed to the flange 45a. .

The hairspring 43 is, for example, a flat whiskers wound spirally in one plane, and the inner end portion of the hairspring 43 is fixed to a portion located above the large-diameter portion 41 a of the balance stem 41 via a whisker ball 47. ing. The balance spring 43 plays a role of storing the power transmitted from the fourth wheel 27 to the escape wheel 35 and transmitting the power to the balance wheel 42 as described above.
In addition, the hairspring 43 of the present embodiment is formed of a general steel material having a negative temperature coefficient of Young's modulus, and has a characteristic that the spring constant decreases as the temperature increases.

  As shown in FIGS. 4 and 5, the balance wheel 42 includes three bimetal portions 50 arranged in the circumferential direction around the axis O of the balance stem 41, and the three bimetal portions 50 and the balance stem 41. And a connecting member 51 that is connected in the radial direction.

The connecting member 51 is disposed coaxially with the axis O, and includes a connecting disc 55 having an axial hole 55a formed at the center thereof, and a connecting ring that surrounds the connecting disc 55 with a gap from the outside in the radial direction. 56, and three connection bridges 57 that connect the outer periphery of the connection disk 55 and the inner periphery of the connection ring 56.
The connecting member 51 is integrally attached to the balance stem 41 by being fixed to the large-diameter portion 41a of the balance stem 41 by, for example, press fitting through the shaft hole 55a.

  Three support protrusions 58 protrude from the outer peripheral portion of the connection ring 56 toward the outer side in the radial direction. These three support protrusions 58 are equally arranged with a certain interval in the circumferential direction. Each support protrusion 58 is formed with an inclined surface 58a that is inclined toward one side (in the direction of arrow Q shown in FIG. 4) in the circumferential direction from the outer peripheral portion of the coupling ring 56 toward the outer side in the radial direction. ing.

  The connection bridge 57 is a member that connects the connection disk 55 and the connection ring 56 in the radial direction, and is evenly arranged at a certain interval in the circumferential direction. In the illustrated example, the three connection bridges 57 and the three support protrusions 58 are disposed in a state where the positions thereof are shifted from each other in the circumferential direction. However, the present invention is not limited to this case.

  The bimetal part 50 is a laminated body in which a first member 60 located on the inner side in the radial direction and a second member 61 located on the outer side in the radial direction of the first member 60 are joined to each other in the radial direction. Yes, it is formed in a strip shape extending in an arc shape along the circumferential direction. And this bimetal part 50 is arrange | positioned in the state which left the space | interval outer side of the connection ring 56 in the radial direction, and was located in a line with the circumferential direction, and fixed end 50A with which the one end part of the circumferential direction was connected with the connection member 51. It is said that.

  Specifically, the fixed end 50 </ b> A of the bimetal part 50 is connected to a surface opposite to the inclined surface 58 a in the support protrusion 58 protruding from the connection ring 56. The bimetal portion 50 extends from the support protrusion 58 in the arrow Q direction along the circumferential direction. Thereby, the three bimetal parts 50 are equally arrange | positioned in the circumferential direction.

The other end in the circumferential direction of the bimetal portion 50 is a free end 50B that is movable in the radial direction by bending deformation accompanying a temperature change. The free end 50 </ b> B is mainly formed by the first member 60, and is formed wider in the radial direction than the other parts of the bimetal portion 50 by projecting inward in the radial direction.
Thereby, the weight of the free end 50 </ b> B is designed to be heavier than the other parts of the bimetal part 50. Moreover, a weight hole 62 is formed in the free end 50B of the present embodiment, and a weight portion 65 (see FIGS. 2 and 3) is attached to the weight hole 62 by, for example, press fitting. Therefore, the free end 50 </ b> B is designed to be sufficiently heavier than the other parts of the bimetal part 50 with the weight of the weight part 65 added.

2 and 3, the weight portion 65 is formed like a rivet with a shaft portion 65a inserted into the weight hole 62 and a head portion 65b exposed on the upper surface of the free end 50B. Take the case as an example.
Further, as shown in FIG. 4, a portion of the free end 50 </ b> B facing inward in the radial direction is opposed to the inclined surface 58 a of the support protrusion 58, and is opposed to the inclined surface 66 inclined according to the inclination of the inclined surface 58 a. It is said that.

  Incidentally, as described above, the bimetal portion 50 is formed by laminating the first member 60 and the second member 61 in the radial direction as shown in FIGS. 4 and 5. It is made of materials with different coefficients of thermal expansion.

Specifically, the first member 60 located inside in the radial direction is formed of a ceramic material, which is a low thermal expansion material, in this embodiment, silicon (Si). On the other hand, the second member 61 located on the outer side in the radial direction is a high thermal expansion material having a larger coefficient of thermal expansion than the first member 60, and is an electroforming metal material, which is gold (Au) in this embodiment. Is formed.
Therefore, when the temperature rises, the second member 61 expands more thermally than the first member 60, so that the bimetal portion 50 has the free end 50B moving inward in the radial direction with the fixed end 50A as a base point. Bends and deforms.

  Further, the first member 60 of this embodiment is formed integrally with the connecting member 51. Accordingly, the connecting member 51 is also formed of silicon, as with the first member 60. That is, in the balance wheel 42 constituting the balance 40, the connecting member 51 and the first member 60 are made of silicon, and only the second member 61 is made of gold.

Moreover, the second member 61 is an electroformed product formed by electroforming, and is tightly bonded to the first member 60 during the gold growth process by electroforming. In addition, both end portions in the circumferential direction of the second member 61 are formed with wedge portions 67 having a V-shape in a plan view and gradually extending in the circumferential direction toward the inner side in the radial direction. It joins in the state engaged with the recessed part 68 of the planar view V shape formed.
Thereby, the second member 61 is joined to the first member 60 in a state where the second member 61 is positioned in the circumferential direction.

Here, as shown in FIG. 6, the bimetal portion 50 of the present embodiment, the thickness of the part thickness T ₁ along the radial direction of the portion located on the fixed end 50A side, which is located on the free end 50B side T It is thicker than ₂ , and gradually becomes thinner as it goes from the fixed end 50A side to the free end 50B side as a whole.
In the present embodiment, the thicknesses of the first member 60 and the second member 61 described above gradually become thinner from the fixed end 50A side toward the free end 50B side. In the illustrated example, the thickness of the portion of the first member 60 located on the fixed end 50A side is S ₁₁ , the thickness of the portion located on the free end 50B side is S ₂₁ (S ₁₁ > S ₂₁ ), of the second member 61, the thickness of the portion where the thickness of the portion located on the fixed end 50A side S12, positioned on the free end 50B side is in _{S 22 (S 12> S 22} ).

In addition, the thickness ratio between the first member 60 and the second member 61 at the same position along the circumferential direction in the bimetal portion 50 is set to be constant over the entire circumferential direction of the bimetal portion 50. In this case, for example, the thickness ratio (S ₁₁ / S ₁₂ ) on the fixed end 50A side is set to be equal to the thickness ratio (S ₂₁ / S ₂₂ ) on the free end 50B side ( (See the following formula (2)).

Furthermore, when the Young's modulus of the first member 60 is E ₁ and the Young's modulus of the second member 61 is E ₂ , the thickness S ₁ of the first member 60 at the same position in the circumferential direction of the bimetal portion 50 (for example, The thickness ratio between S ₁₁ and S ₂₁ ) and the thickness S ₂ of the second member 61 (for example, S ₂₁ and S ₂₂ ) is preferably set so as to satisfy the following expression (3). Thereby, the deformation amount to the radial direction in the arbitrary positions along the circumferential direction of the bimetal part 50 can be enlarged.

[Method for manufacturing balance]
Next, a method for manufacturing the balance with hairspring 40 will be described with reference to the drawings.
The method of manufacturing the balance with hairspring 40 includes a step of manufacturing the balance stem 41, a step of manufacturing the balance wheel 42, a step of manufacturing the hairspring 43, and a step of assembling them together. Here, the process of manufacturing the main wheel 42 will be described in detail.

First, as shown in FIG. 7, after preparing a silicon substrate 70 to be a connection member 51 and a first member 60 later, a silicon oxide film (SiO ₂ ) 71 is formed on the surface thereof. At this time, a silicon substrate 70 that is thicker than the thickness of the balance wheel 42 is used. The silicon oxide film 71 is formed by a method such as plasma enhanced chemical vapor deposition (PCVD) or thermal oxidation.

  Here, in order to simplify the description, a case where only one balance wheel 42 is manufactured from a silicon substrate 70 having a square shape in plan view will be described as an example. However, a wafer-like silicon substrate may be prepared and a plurality of balance wheels 42 may be manufactured simultaneously.

  Subsequently, as shown in FIGS. 8 and 9, a part of the silicon oxide film 71 is selectively removed by etching or the like so that the three arc-shaped groove portions 72 are arranged at intervals in the circumferential direction. Form. The groove 72 is a groove for forming an electroforming guide wall 70 </ b> A (see FIG. 15) to be formed later, and is formed so as to be positioned on the outer side in the radial direction than the second member 61.

  Subsequently, as shown in FIGS. 10 to 12, after forming a photoresist on the inner region surrounded by the three grooves 72 on the silicon oxide film 71, a resist pattern 73 is formed by patterning the photoresist. . At this time, the resist pattern main body 73A patterned according to the shapes of the connecting member 51 and the first member 60, and the guide wall pattern in which the both end portions in the circumferential direction are connected to the resist pattern 73 while entering the three groove portions 72 described above. The resist pattern 73 is formed so as to be composed of 73B.

  Note that the photoresist may be formed by a general method such as spin coating or spray coating. The resist pattern 73 may be formed by patterning a photoresist by a general method such as a photolithography technique.

Subsequently, as shown in FIGS. 13 and 14, a region of the silicon oxide film 71 that is not masked by the resist pattern 73 is selectively removed. Specifically, the silicon oxide film 71 is removed by wet etching using a buffered hydrofluoric acid aqueous solution or etching processing by dry etching such as reactive ion etching (RIE).
Thereby, the silicon oxide film 71 can be left only under the resist pattern 73, and the silicon oxide film 71 can be patterned into a shape following the resist pattern 73.

Subsequently, as shown in FIGS. 15 and 16, a region of the silicon substrate 70 that is not masked by the resist pattern 73 and the silicon oxide film 71 is selectively removed. Specifically, the silicon substrate 70 is removed by etching using dry etching such as deep reactive ion etching (DRIE).
Thereby, the silicon substrate 70 can be left only under the resist pattern 73 and the silicon oxide film 71, and the silicon substrate 70 can be patterned into a shape following the resist pattern 73.

  In particular, the portion of the patterned silicon substrate 70 left under the guide wall pattern 73B functions as an electroforming guide wall 70A.

  Subsequently, as shown in FIGS. 17 and 18, the resist pattern 73 used as a mask is removed. Examples of this removal method include dry etching using fuming nitric acid and dry etching using oxygen plasma.

  Through the above steps, the silicon substrate 70 is processed by semiconductor technology, and the three first members 60 are integrally connected to the connecting member 51, and the open space S for electroforming is formed between each first member 60. The precursor 75 in which the guide wall 70A for electroforming to be defined is integrally connected to each first member 60 can be obtained.

  After the precursor 75 is formed, the second member 61 is formed by growing gold in the electroforming open space S by electroforming, and the first member 60 and the second member 61 are joined to each other. An electroforming process for forming 50 is performed. This electroforming process will be specifically described.

  First, as shown in FIGS. 19 and 20, after preparing a first support substrate 80 in which an adhesive layer 80C is bonded to the substrate body 80A via an electrode layer 80B, for example, the precursor 75 is turned upside down. Then, the patterned silicon oxide film 71 is bonded to the adhesive layer 80C. In the illustrated example, the precursor 75 and the first support substrate 80 are bonded to such an extent that the silicon oxide film 71 is embedded in the adhesive layer 80C.

  The adhesive layer 80C is not particularly limited, but for example, a photoresist is preferably used. In this case, bonding may be performed in a state where the photoresist is in a paste state, and then the photoresist may be cured to a state where the paste is removed.

And after performing the said bonding, as shown in FIG. 19, the part connected to the open space S for electroforming of the precursor 75 among the adhesive layers 80C is selectively removed. Thereby, the electrode layer 80B can be exposed in the open space S for electroforming.
At this time, for example, when the adhesive layer 80 </ b> C is a photoresist, it is possible to easily perform an operation of selectively removing by a photolithography technique.

Subsequently, as shown in FIGS. 21 and 22, electroforming is performed using the electrode layer 80 </ b> B, gold is gradually grown from the electrode layer 80 </ b> B in the electroforming open space S, and the electroforming open space S An electroformed product 81 is produced that fills the interior and further expands the open space S for electroforming. Then, the expanded electroformed product 81 is polished so as to be flush with the precursor 75. Thereby, this electroformed product 81 can be used as the second member 61, and the bimetal portion 50 in which the first member 60 and the second member 61 are joined can be formed.
In addition, when performing the said grinding | polishing, you may grind | polish the silicon substrate 70 of the precursor 75 simultaneously.

At this stage, the above-described electroforming process is completed. In FIGS. 21 and 22, illustration of general structural members (such as an electroforming tank) necessary for electroforming is omitted.
After the electroforming is completed, a removal step of removing the electroforming guide wall 70A from the first member 60 is performed. This removal step will be specifically described.

  First, as shown in FIG. 23, after preparing the second support substrate 85 in which the adhesive layer 85B is formed on the substrate body 85A, the precursor 75 removed from the first support substrate 80 is reversed again and again, The surface of the silicon substrate 70 opposite to the side on which the silicon oxide film 71 is formed is bonded to the adhesive layer 85B.

Subsequently, as shown in FIG. 24, only the electroforming guide wall 70A of the precursor 75 is selectively removed. Specifically, in the precursor 75, for example, a region other than the electroforming guide wall 70A is covered with a mask (not shown) from above, and is masked by an etching process using dry etching such as deep reactive ion etching (DRIE). The electroforming guide wall 70A which is not present is removed.
At this stage, the removal process is completed.

Subsequently, after the second support substrate 85 is removed as shown in FIG. 25, the remaining silicon oxide film 71 is removed by wet etching using BHF, for example, as shown in FIGS.
The silicon oxide film 71 is not necessarily removed, but is preferably removed. In FIGS. 26 and 27, since the thickness of the silicon oxide film 71 is exaggerated, a step is generated between the first member 60 and the second member 61. It is slightly (for example, about 1 μm), and is substantially equivalent to no step between the first member 60 and the second member 61 as shown in FIG.

Finally, the balance wheel 42 shown in FIG. 2 can be manufactured by fixing the weight portion 65 to the weight hole 62 by press-fitting or the like.
Thereafter, as described above, the balance 40 and the balance spring 43 manufactured separately and the balance wheel 42 are assembled together to complete the production of the balance 40.

(Temperature correction method)
Next, a method for correcting the temperature of the moment of inertia using the balance 40 will be described.
According to the balance with hairspring 40 of the present embodiment, as shown in FIG. 2, when a temperature change occurs, the bimetal portion 50 has the fixed end 50 </ b> A as a base point due to a difference in thermal expansion coefficient between the first member 60 and the second member 61. Since it is bent and deformed in the radial direction, the free end 50B of the bimetal portion 50 can be moved toward the inside or the outside in the radial direction. That is, when the temperature rises, the bimetal part 50 bends and deforms inward in the radial direction, so that the free end 50B can be moved toward the inside in the radial direction. It can be moved outward in the radial direction.

  Therefore, the average diameter of the balance wheel 42 can be reduced or expanded, and the moment of inertia of the balance 40 can be changed by changing the distance from the axis O of the balance stem 41. That is, when the temperature rises, the average diameter of the balance wheel 42 can be reduced to reduce the moment of inertia, and when the temperature drops, the average diameter of the balance wheel 42 can be increased to increase the moment of inertia. Can be bigger. Thereby, the inclination of the temperature characteristic of the moment of inertia can be changed to a negative inclination, and temperature correction can be performed.

  That is, even if the hairspring 43 having a negative temperature coefficient of Young's modulus is provided, the moment of inertia can be reduced simultaneously with the decrease of the Young's modulus of the hairspring 43 when the temperature rises. The period can be kept constant and temperature correction can be performed. Further, when the temperature is lowered, the moment of inertia can be increased simultaneously with the increase of the Young's modulus of the hairspring 43, so that the vibration cycle of the balance 40 can be kept constant and the temperature can be corrected.

FIG. 28 is a graph showing the radius variation ΔR (mm) with respect to the arc angle θ (deg) in the bimetal part 50.
The arc angle θ is a straight line connecting the fixed end 50A of the bimetal portion 50 and the axis O among the central angles around the axis O, and the reference line (0 (deg)) is defined from the reference line to the bimetal portion 50. It is an angle formed by an arc up to an arbitrary position along the circumferential direction. Further, as shown in FIG. 6, the radius change amount ΔR is a change vector (for example, from the initial position (solid line in the figure) to the change position (dashed line in the figure) at an arbitrary position along the circumferential direction of the bimetal portion 50. , H ₁ , H ₂ ), the radial component toward the axis O. Further, in the graph shown in FIG. 28, the above-described bimetal portion 50 of the present embodiment is indicated by a solid line, and has the same thickness (for example, T ₁ ) as the fixed end 50A of the present embodiment from the fixed end 50A to the free end 50B. The extending bimetal part 50 is shown by a broken line as a comparative example.

Here, as shown in FIGS. 6 and 28, according to the present embodiment, since the thickness of the bimetal portion 50 gradually decreases from the fixed end 50A side toward the free end 50B side, the fixed end 50A side It becomes easy to bend and deform as it goes to the free end 50B side. Specifically, when the temperature rises, the bimetal part 50 is deformed so as to incline radially inward as it goes to the free end 50B side. Therefore, the radius change amount ΔR ₂ on the free end 50B side of the bimetal portion 50 (for example, the center of the weight portion 65) is larger than the radius change amount ΔR ₁ on the fixed end 50A side.

Accordingly, the bimetal portion 50 of the present embodiment, while maintaining the thickness of the fixed end 50A side, it is found that can be increased compared to the radius variation [Delta] R ₂ at the free end 50B side to the comparative example.
Further, according to this embodiment, as change vector of H ₂ free end 50B as the temperature changes toward the direction of the axis O, in other words, the axis from the distal end side of the bimetal 50 is present at the free end 50B O Therefore, the radius change amount ΔR can be increased as compared with the case where the thickness is constant. Therefore, it is possible to effectively secure the radius variation [Delta] R ₂ even in a limited arc length of the bimetal unit 50.

Thus, according to the balance 40 of the present embodiment, the bimetal portion 50 is gradually thinner than the free end 50B side from the fixed end 50A side, so ensuring the thickness on the fixed end 50A side, A radius change amount ΔR ₂ on the free end 50B side can be secured. Therefore, it is possible to secure the necessary temperature correction amount of the moment of inertia while ensuring the strength of the bimetal portion 50.
As a result, the plastic deformation and damage of the bimetal part 50 due to impact or the like can be suppressed, the temperature correction work can be stably performed as intended, the rate is difficult to change due to a temperature change, and the temperature compensation performance is excellent. A high-quality balance 40 can be obtained.

In particular, in the present embodiment, the balance member 51 and the first member 60 are formed of a ceramic material such as silicon, so that the balance 40 can be formed using a semiconductor process such as a photolithography technique. In this case, it is possible to provide the balance 40 with a high degree of freedom in shape and high accuracy as compared with the case where the connecting member 51 and the first member 60 are formed by machining or the like. Moreover, since it can form simply and efficiently, it is easy to improve and improve manufacturing efficiency.
Of the first member 60 and the second member 61, at least the first member 60 is formed to be gradually thinner from the fixed end 50 </ b> A side toward the free end 50 </ b> B side, so that the first member is made of a ceramic material that is a brittle material. Even when 60 is formed, it is possible to secure the amount of change in radius after securing the strength on the fixed end 50A side.

Furthermore, since the thickness ratio of the first member 60 and the second member 61 in the radial direction is constant from the fixed end 50A side to the free end 50B side, the degree of deformation of the first member 60 and the second member 61 However, it becomes constant from the fixed end 50A side to the free end 50B side based on the thermal expansion coefficient and Young's modulus E ₁ and E ₂ . That is, since variation in the degree of deformation due to the difference in thickness ratio can be suppressed, the bimetal part 50 can be stably deformed, and in the circumferential direction of the bimetal part 50 according to the temperature correction amount of the required moment of inertia. It becomes easy to set the length along.

Further, according to the movement 10 of the present embodiment, since the temperature compensation balance 40 having high temperature compensation performance is provided, it is possible to obtain a high-quality movement with less error in yield.
Furthermore, according to the mechanical timepiece 1 of this embodiment provided with the movement 10, a high-quality timepiece having a low rate error is similarly obtained.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the number of the bimetal portions 50 is three, but may be two or four or more. Even in these cases, the bimetal portions 50 may be evenly arranged in the circumferential direction, and similar effects can be obtained. Moreover, the shape of the connection member 51 is an example, and may be changed as appropriate.

  In the above embodiment, a constant elastic material such as Elinvar is used as the material of the hairspring 43, and the second member 61 in the bimetal portion 50 is made of a metal material having a lower thermal expansion coefficient than the first member 60 made of a ceramic material. It may be formed. Even in this case, the temperature characteristic of the moment of inertia can be finely adjusted so as to cancel the positive temperature coefficient of the hairspring 43.

Moreover, in the said embodiment, although the connection member 51 and the 1st member 60 which comprise the balance wheel 42 were made into silicon | silicone, it should just be formed with the ceramic material, and is not limited to silicon. For example, silicon carbide (SiC), silicon dioxide (SiO ₂ ), sapphire, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), glassy carbon (C), or the like may be employed as the ceramic material. . Even if any of these is adopted, it is possible to suitably perform the etching process, particularly the dry etching process, and the connecting member 51 and the first member 60 can be formed more simply and efficiently, further increasing the production efficiency. easy.
Further, for example, the first member 60 can be made of a metal material other than a ceramic material. For example, an alloy having a low coefficient of thermal expansion such as Invar can be used.

  In addition, as a ceramic material in this embodiment, it is preferable to have insulation with high electrical resistance. Further, a coating film such as an oxide film or a nitride film may be provided on the surfaces of the connecting member 51 and the first member 60.

The second member 61 constituting the balance wheel 42 is gold. However, the first member 60 may be any metal material that has a different coefficient of thermal expansion (preferably large) and can be electroformed, and is limited to gold. Is not to be done.
For example, Au, Ni, Ni alloy (Ni—Fe, etc.), Sn, Sn alloy (Sn—Cu, etc.) may be adopted. Even if any of these is adopted, the metal material can be grown smoothly by electroforming, and the second member 61 can be formed efficiently.
Further, for example, the second member 61 can be made of a material having a larger coefficient of thermal expansion than the above-described metals and alloys. For example, it can be made of stainless steel or brass having a higher thermal expansion coefficient than the above-mentioned invar.

Moreover, in the said embodiment, although the weight part 65 was provided in the free end 50B of the bimetal part 50, this weight part 65 is not essential and does not need to be provided. However, since the weight of the free end 50B can be increased by providing the weight portion 65, the temperature of the moment of inertia can be more effectively corrected for the amount of change in radius at the free end 50B. It is easy to improve the compensation performance.
The shape of the weight portion 65 may be determined from the weight of the weight portion 65 and the amount of inertia moment required for the weight portion 65.

  Moreover, when providing the weight part 65, it is not restricted to the weight part 65 fixed to the weight hole 62 like the said embodiment by press injection etc., You may change freely. For example, an electroformed product obtained by growing gold in the weight hole 62 by electroforming may be used as the weight portion.

  Moreover, although the said embodiment demonstrated the structure which makes both the 1st member 60 and the 2nd member 61 gradually thin as it goes to the free end 50B side from the fixed end 50A side, it is not restricted to this, The bimetal part 50 whole is demonstrated. It is only necessary that the thickness is gradually reduced from the fixed end 50A side toward the free end 50B side. In other words, at least one of the first member 60 and the second member 61 (preferably the first member 60) may be formed so as to gradually become thinner from the fixed end 50A side toward the free end 50B side. Absent.

Further, the first member 60 and the second member 61 may have the same thickness, or one of them may be thicker. However, among the first member 60 and the second member 61, it is preferable to thin a material having a high Young's modulus.
Moreover, although embodiment mentioned above demonstrated the case where the thickness ratio of the 1st member 60 and the 2nd member 61 was set uniformly over the whole circumferential direction of the bimetal part 50, it is not restricted to this. Alternatively, the thickness ratio may be set to change along the circumferential direction.
Further, when the first member 60 is made of a metal material having a low coefficient of thermal expansion such as Invar other than the ceramic material and the second member 61 is made of stainless steel or brass having a high coefficient of thermal expansion, cutting, etching, laser, etc. The outer shape can be formed by processing or the like. Alternatively, the first member 60 and the second member 61 may be formed separately, and the first member 60 and the second member 61 may be joined by fitting, bonding, welding, or the like.

  In addition, in the range which does not deviate from the meaning of this invention, it is possible to replace suitably the component in the above-mentioned embodiment with a well-known component, and you may combine each above-mentioned modification suitably.

O ... Axis (rotating axis)
S ₁₁ , S ₁₂ , S ₂₁ , S ₂₂ , T ₁ , T ₂ ... Thickness 1 ... Mechanical watch 10 ... Movement (watch movement)
22 ... barrel wheel 28 ... front wheel train
30 ... Escapement mechanism 31 ... Speed control mechanism 40 ... Balance (temperature compensation type balance)
DESCRIPTION OF SYMBOLS 41 ... Tenshin 42 ... Balance wheel 50 ... Bimetal part 50A ... Fixed end 50B ... Free end 51 ... Connecting member 60 ... First member 61 ... Second member 65 ... Weight part

Claims (6)

With the balance rotating around the axis,
A plurality of bimetal portions that are arranged in a circumferential direction around the rotation axis of the balance shaft and extend in an arc shape along the circumferential direction of the rotation shaft, and a diameter of each of the plurality of bimetal portions and the balance stem A balance wheel having a connecting member connected in the direction,
The bimetal portion is a laminated body in which a first member and a second member having different thermal expansion coefficients are overlapped in the radial direction, and one end portion in the circumferential direction is connected to the connecting member, and the other in the circumferential direction. The end is a free end,
The temperature-compensated balance balance characterized in that the bimetal portion gradually decreases in thickness along the radial direction from the fixed end side toward the free end side. The first member is disposed radially inward of the second member, and is integrally formed with the connecting member by a ceramic material.
The thickness along the radial direction of at least the first member among the first member and the second member is gradually reduced from the fixed end side toward the free end side. The temperature-compensated balance according to 1.   3. The temperature compensation type according to claim 1, wherein a thickness ratio of the first member and the second member in a radial direction is constant from the fixed end side to the free end side. Tempu.   The temperature compensated balance according to any one of claims 1 to 3, wherein a weight portion is provided at the free end of the bimetal portion. A barrel complete with a power source;
A train wheel for transmitting the rotational force of the barrel wheel,
An escapement mechanism for controlling rotation of the train wheel;
2. A timepiece movement comprising: the temperature compensation balance according to claim 1, wherein the escapement mechanism is speed-controlled.   A mechanical timepiece comprising the timepiece movement according to claim 5.

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