JP2014062783A - Balance wheel, watch movement, watch, and method for manufacturing balance wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balance wheel, a watch movement, a watch, and a method for manufacturing the balance wheel capable of improving machining accuracy as a structure enabled to select various metals, capable of being hardly affected by magnetism, and capable of stably reducing the temperature dependency of a vibration frequency.SOLUTION: A rim part 25 of a balance wheel 21 is formed by stacking a low thermal expansive metal plate 27 arranged on the inner peripheral side and a high thermal expansive metal plate 28 arranged on the outer peripheral side, and an uncross part 26 of the balance wheel 21 is configured by an approximately circular-arc first arm part 31 and second arm part 32 formed by stacking a high thermal expansive metal plate 33 arranged on the inner peripheral surface side and a low thermal expansive metal plate 34 arranged on the outer peripheral surface side.

Description

  The present invention relates to a balance with a balance, a movement for a timepiece, a timepiece, and a balance with a balance.

For example, a speed governor of a mechanical timepiece includes a balance with a balance and a hairspring. The balance with hairspring is a member that includes a balance and a balance wheel fixed to the balance, and vibrates by rotating forward and backward periodically around the rotation axis of the balance. At this time, it is important that the vibration period 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 cycle is likely to change due to various causes, and for example, changes due to temperature changes.
Here, the vibration period T is expressed by the following equation (1).

In the 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.
As a metal material used for the balance with hairspring, a material having a positive linear expansion coefficient is generally used and expands due to a temperature rise. For this reason, the diameter of the balance wheel is increased, and the moment of inertia is increased. 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 accordingly, and the spring constant of the mainspring decreases. Therefore, as apparent from the equation (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.

Then, the following two methods are known as a countermeasure for improving the temperature characteristic of the vibration cycle of the balance with hairspring.
As a first method, by adopting a constant elastic material such as coelin bar as a material for the hairspring, the temperature coefficient of Young's modulus near the operating temperature range of the watch (for example, 23 ° C. ± 15 ° C.) is positive. It is a method. As a result, the change in the moment of inertia of the balance with respect to the temperature can be canceled within the above operating temperature range, and the temperature dependence of the vibration cycle of the balance can be kept low.

  As a second method, a metal plate made of a material having a different coefficient of thermal expansion, in which one end portion in the circumferential direction is a fixed end and the other end portion in the circumferential direction is a free end on a part of the rim portion constituting the balance wheel. There is known a method of adopting a so-called bimetal structure in which slabs are joined in the radial direction (see Non-Patent Document 1).

More specifically, a balance with a bimetal structure for the rim will be described with reference to FIG.
FIG. 18 is a plan view of a conventional balance.
As shown in the drawing, a conventional balance 700 includes a balance stem 711 that is rotatably supported around a rotation axis O, and a balance wheel 712 fixed to the balance stem 711.
In the following description, a direction orthogonal to the rotation axis O is referred to as a radial direction, and a direction around the rotation axis O is referred to as a circumferential direction.

The balance wheel 712 is formed in a substantially arc shape so as to surround the balance stem 711 from the outer side in the radial direction about a half circumference, and has two rim portions 720 disposed on both sides around the balance stem 711, and these rim portions 720 An amid portion 721 for connecting the balance stem 711 in the radial direction is provided.
The rim portion 720 is joined so that a low thermal expansion metal plate 725 and a high thermal expansion metal plate 726 made of materials having different coefficients of thermal expansion overlap in the radial direction. Of these metal plates 725 and 726, the low thermal expansion metal plate 725 located on the radially inner side, that is, on the inner peripheral surface side, is formed of invar, which is a material having a low coefficient of thermal expansion. On the other hand, the high thermal expansion metal plate 726 located on the outer side in the radial direction, that is, on the outer peripheral surface side is formed of brass which is a material having a higher thermal expansion coefficient than the low thermal expansion metal plate 725.

The amid portion 721 is a belt-like member extending in the radial direction so as to pass through the balance stem 711, and the longitudinal center thereof is fixed to the balance stem 711. Further, the amid portion 721 is formed of a thermal expansion material such as invar, like the low thermal expansion metal plate 725 of the rim portion 720.
One end of each rim portion 720 is fixed to each end of the amid portion 721. Thereby, both ends of each rim portion 720 are set to a fixed end 720a fixed to the amidor portion 721 and a free end 720b located on the opposite end to the fixed end 720a. In addition, the two rim portions 720 are arranged in a point-symmetric manner with the balance 711 as the center, and the two rim portions 720 surround the entire circumference of the balance 711. Furthermore, weight portions 727 are provided at the free ends 720b.

  Under such a configuration, when the temperature rises, the free end 720b side is deformed inward so as to move inward in the radial direction due to the difference in thermal expansion coefficient between the two metal plates 725 and 726 of the rim portion 720 ( (See arrow Y700 in FIG. 18). Accordingly, the average diameter of the rim portion 720 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 cycle of the balance with hairspring 700 can be suppressed to a low level. Further, by changing the attachment position of the weight part 727 provided on the rim part 720 along the circumferential direction, the temperature dependency of the vibration period of the balance with hairspring 700 can be more effectively suppressed to be low.

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

By the way, in the above-described prior art, as the low thermal expansion metal plate 725, invar which is a material having a low thermal expansion coefficient is used, while as the high thermal expansion metal plate 726, brass which is a material having a high thermal expansion coefficient is used. Both are joined by brazing. As described above, in order to sufficiently change the rim portion 720 according to the temperature change, usable materials are limited.
Here, when brazing invar and brass, after processing the invar (processing of the part that becomes the interface between the two types of metal), remove it once from the processing machine, fix the brass ring by brazing, and reprocess Fix to the machine and process into the shape of a balance wheel. At this time, since there is a change of the processing machine, the central axis of the boundary surface (cylindrical shape) of the two types of metal and the central axis of the inner and outer surfaces of the balance wheel are shifted, and the thickness of the two types of metal in the bimetallic structure The ratio tends to vary. In addition, variations in the metal thickness of the joint portion can be considered, and there is a problem that it is difficult to perform highly accurate processing such as making the thickness ratio of the two types of metal in the rim portion uniform.

  Further, the thermal expansion coefficient of Invar changes due to the influence of magnetism, and the displacement amount of the rim portion 720 when the temperature rises becomes small. For this reason, there is a problem that it is difficult to stably keep the temperature dependency of the vibration period of the balance with hairspring 700 low.

  Accordingly, the present invention has been made in view of the above-described circumstances, and can improve the processing accuracy as a structure in which various metals can be selected, and can be less affected by magnetism. The present invention provides a balance with a temperature, a movement for a timepiece, a timepiece, and a balance with which the temperature dependence of the vibration period can be stably kept low.

  In order to solve the above-mentioned problem, a balance, at least two rim portions formed in an arc shape so as to surround the balance stem from the outside in the radial direction, and one end of the rim portion and an outer peripheral portion of the balance A balance wheel having a connecting amid portion, wherein the rim portion is formed by laminating two materials having different coefficients of thermal expansion in a radial direction, and at least a portion of the amid portion is heated. It is formed by laminating two materials having different expansion coefficients in the radial direction, and is formed so that an intermediate portion protrudes from both end portions of the amid portion, and according to a temperature change, the free end of the rim portion And a connecting end of the amid portion with the rim portion is deformed in a direction opposite to each other.

  With this configuration, when the same material as the conventional material is used for the bimetal structure, the amount of displacement by which the free end of the rim portion moves toward the inside in the radial direction when the temperature rises can be made larger than in the past. For this reason, the difference of the thermal expansion coefficient of two materials which comprise a rim | limb part and an amider part can be set smaller than before. As a result, the choice of materials to be selected for a bimetallic structure can be increased, and by selecting a material that can use a highly accurate processing method, the processing accuracy of the balance can be improved as a result. it can. In addition, the displacement amount of the rim portion can be easily adjusted, and for example, even when the weight portion is provided on the rim portion, the attachment position of the weight portion can be easily adjusted.

  Furthermore, since a nonmagnetic material other than Invar can be used as the material constituting the rim portion as in the prior art, it is possible to prevent the displacement amount of the rim portion from being reduced due to the influence of magnetism. For this reason, the temperature dependence of the vibration cycle of the balance with hairspring can be stably suppressed to a low level.

  In the balance according to the present invention, the rim portion is set so that the thermal expansion coefficient of the material on the radially outer side of the rim portion is larger than the material on the radially inner side of the rim portion. It is formed so as to have an arc-shaped portion that is partially curved, and at least the arc-shaped portion is formed by laminating two materials having different coefficients of thermal expansion in the radial direction, and a material radially inward of the arc-shaped portion. Further, the coefficient of thermal expansion of the material on the radially outer side of the arc-shaped portion is set to be smaller.

  By configuring in this way, it is possible to reliably change both the rim part and the amid part with a temperature change. For this reason, it becomes possible to provide the balance with which various metals can be selected reliably.

  The balance according to the present invention is provided with at least one weight portion on the rim portion, and the total weight of the weight portion provided on the free end side with respect to the longitudinal center of the rim portion is provided on the fixed end side. It is set so that it may become larger than the total weight of a weight part.

  By comprising in this way, the variation | change_quantity of the moment of inertia accompanying the displacement of a rim | limb part can be enlarged. For this reason, it becomes possible to suppress the temperature dependence of the vibration cycle of the balance with hair effectively.

  The balance according to the present invention is characterized in that the position of the fixed end on the balance side in the amid portion is located on the opposite side from the fixed end of the corresponding rim portion with the balance in the center. And

  By comprising in this way, the full length of an amid part can be set long compared with the case where the position of the fixed end connected with the spring of an amid part is set to the free end side of an amid part. For this reason, the amount of displacement of the amid portion accompanying the temperature change can be increased, and as a result, the amount of displacement of the rim portion can be reliably increased.

  The balance with hairspring according to the present invention has a plurality of arm portions formed in an arc shape by laminating two materials having different coefficients of thermal expansion in the radial direction. The end portions are connected to each other through a connecting member.

  By comprising in this way, the displacement amount of the whole amidor part can be enlarged more by displacing each arm part individually. In addition to this, since the arm portions can be arranged while being wrapped in the radial direction, the size of each arm portion can be set as large as possible, and the displacement amount of the entire amid portion can be further increased. .

  The balance with hairspring according to the present invention is characterized in that the connecting member is formed of a material having a low coefficient of thermal expansion among two materials having different coefficients of thermal expansion.

  By configuring in this way, it is possible to effectively set the displacement amount of the entire amid portion due to a temperature change as compared with the case where the connecting member is formed of the same material as the material on the radially inner side of the amid portion. .

  A timepiece movement according to the present invention includes a barrel wheel having a power source, a train wheel that transmits a rotational force of the barrel wheel, an escapement mechanism that controls rotation of the train wheel, and a speed control of the escapement mechanism. The balance according to claim 1 is provided.

  By configuring in this way, it is possible to provide a timepiece movement that can improve the machining accuracy, easily assemble and adjust the rim, and can stably suppress the temperature dependence of the vibration period to a low level. be able to.

  The timepiece according to the present invention includes a timepiece movement.

  By configuring in this way, it is possible to provide a timepiece capable of improving the machining accuracy and easily assembling and adjusting the rim portion, and stably keeping the temperature dependence of the vibration period low. it can.

  The balance with hairspring manufacturing method according to the present invention comprises a rotatably supported balance, an arc-shaped rim that surrounds the balance from the radially outer side and is arranged coaxially with the balance, and one end of the rim. And a balance wheel having an amid portion for connecting the outer periphery of the balance stem in the radial direction, wherein the rim portion is patterned in an arc shape by arranging two materials having different coefficients of thermal expansion. The amid portion is formed so as to have at least part of an arc-shaped portion, and the arc-shaped portion is formed by arranging two materials having different coefficients of thermal expansion and patterning them in an arc shape. To do.

  By providing such a method, it is possible to improve the processing accuracy, easily assemble and adjust the rim portion, and provide a balance that can stably suppress the temperature dependence of the vibration cycle. Can do.

  According to the present invention, when the same material as the conventional material is used as the bimetal structure, the amount of displacement by which the free end of the rim portion moves toward the inside in the radial direction when the temperature rises can be made larger than before. For this reason, the difference of the thermal expansion coefficient of two materials which comprise a rim | limb part and an amider part can be set smaller than before. As a result, the choice of materials to be selected for a bimetallic structure can be increased, and by selecting a material that can use a highly accurate processing method, the processing accuracy of the balance can be improved as a result. it can. In addition, the displacement amount of the rim portion can be easily adjusted, and for example, even when the weight portion is provided on the rim portion, the attachment position of the weight portion can be easily adjusted.

  Furthermore, since a nonmagnetic material other than Invar can be used as the material constituting the rim portion as in the prior art, it is possible to prevent the displacement amount of the rim portion from being reduced due to the influence of magnetism. For this reason, the temperature dependence of the vibration cycle of the balance with hairspring can be stably suppressed to a low level.

It is a partially notched top view of the complete front side of the mechanical timepiece according to the first embodiment of the present invention. It is a perspective view of the balance with a balance in a 1st embodiment of the present invention. It is a longitudinal cross-sectional view of the balance with a balance in 1st Embodiment of this invention. It is action | operation explanatory drawing of the balance with the temperature rise in 1st Embodiment of this invention. It is action | operation explanatory drawing of the balance with the temperature fall in 1st Embodiment of this invention. It is explanatory drawing which compared the displacement amount of the rim | limb part in 1st Embodiment of this invention at the time of temperature rise, and the conventional rim | limb part. It is explanatory drawing which compared the displacement amount of the rim | limb part in 1st Embodiment of this invention at the time of temperature fall, and the conventional rim | limb part. It is the graph which showed the change rate of the inertia moment of the balance in 1st Embodiment of this invention, and compared with the change rate of the inertial moment of the conventional balance. It is a top view of the balance with a balance in a 2nd embodiment of the present invention. It is a top view of the balance with a balance in a 3rd embodiment of the present invention. It is a top view of the balance with a balance in a 4th embodiment of the present invention. It is a longitudinal cross-sectional view of the balance with a balance in 4th Embodiment of this invention. It is a top view of the balance with a balance in a 5th embodiment of the present invention. It is a longitudinal cross-sectional view of the balance with a balance in 5th Embodiment of this invention. It is a top view of the balance with a balance in a 6th embodiment of the present invention. It is a top view of the balance with a balance in a 7th embodiment of the present invention. It is a top view of the balance with the eighth embodiment of the present invention. It is a top view of the conventional balance.

(First embodiment)
(Mechanical watch)
Next, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a partially cutaway plan view of a complete front side of a mechanical timepiece which is an example of a timepiece according to the present invention. In the following description, a mechanical body including a timepiece driving portion is referred to as a “movement”. A state in which a dial and hands are attached to the movement and put into a watch case to make a finished product is called “complete” of the watch. Of the two sides of the base plate constituting the watch substrate, the glass case side of the watch case, that is, the dial plate side is called the “back side” or “glass side” or “dial side” of the movement. . Of the two sides of the main plate, the side with the back cover of the watch case, that is, the side opposite to the dial is referred to as “front side” or “back side” of the movement.

As shown in FIG. 1, the complete 1 a of the mechanical timepiece 1 has a movement 100 housed in a timepiece case 3, and the movement 100 has a dial 2 having a scale 3 a indicating information about time, and a time. An hour hand 4a for indicating, a minute hand 4b for indicating minute, and a hand 4 including a second hand 4c for indicating second are provided.
Further, a crown 5 is provided on the side surface of the watch case 3 on the 3 o'clock side. The crown 5 is for operating the movement 100 from the outside of the watch case 3, and is integrated with a winding stem 10 inserted into the watch case 3 from the 3 o'clock side surface of the watch case 3. The winding stem 10 is provided so as to be rotatable about an axis with respect to the watch case 3. A movement 100 is linked to the opposite side of the winding stem 10 from the crown 5.

The movement 100 includes a barrel wheel 120, a second wheel 124, a third wheel 126, and a fourth wheel 128 that constitute a front wheel train, and an escapement and speed control mechanism 20 for controlling the rotation of the front wheel train. Have. The front train wheel is rotatably supported by a ground plate and a train wheel bridge (not shown) arranged on the front side and the back side so as to sandwich the front train wheel.
When the crown 5 is rotated, the winding stem 10 integrated with the crown 5 rotates, and the mainspring (not shown) housed in the barrel complete 120 is wound up.

When the barrel wheel 120 is rotated by the restoring force of the mainspring, the second wheel 124, the third wheel 126, the fourth wheel 128, and the escape wheel 130 constituting the escapement and speed control mechanism 20 are rotated by the rotation of the barrel wheel 120. Rotate sequentially.
Under such a configuration, when the center wheel & pinion 124 is rotated, a cylindrical pinion (not shown) is simultaneously rotated based on the rotation, and the minute hand 4b attached to the cylindrical pinion indicates "minute". Further, the hour wheel (not shown) rotates through the rotation of the hour wheel (not shown) based on the rotation of the hour pinion, and the hour hand 4a attached to the hour wheel displays “hour”.

  The escapement and speed control mechanism 20 includes an ankle 142 and a balance 21 in addition to the escape wheel & pinion 130. Teeth 130 a are formed on the outer periphery of the escape wheel & pinion 130. The ankle 142 is rotatably supported between a ground plate (not shown) and an ankle receiver, and includes a pair of pallets 142a and 142b. The escape wheel 130 is temporarily stopped in a state where one pallet 142a of the ankle 142 is engaged with the teeth 130a of the escape wheel 130.

(Tempo)
FIG. 2 is a perspective view of the balance with hairspring, and FIG. 3 is a longitudinal sectional view of the balance with the balance.
As shown in FIG. 1 to FIG. 3, the balance with hairspring 21 reciprocally rotates at a constant cycle, so that a pair of pallets 142 a of the ankle 142 are alternately engaged with the teeth 130 a of the escape wheel 130. The gear 130 is escaped at a constant speed.
The balance with hairspring 21 has a balance stem 22 supported so as to be rotatable around the rotation axis O, a balance wheel 23 fixed to the balance stem 22, and a hairspring (not shown). Then, the balance spring is rolled up or loosened, so that the balance with hairspring 21 rotates around the rotation axis O in a forward and reverse direction with a constant vibration cycle.

The balance stem 22 is a rotary shaft body that extends vertically along the rotary shaft O, and has an upper end portion and a lower end portion that are rotatably supported by a base plate and a balance holder (not shown), respectively. The balance stem 22 is formed so as to be gradually reduced in diameter by a step as it goes to both ends, and is a large-diameter portion 22a in which the shaft diameter at the central portion in the axial direction is the largest.
A swing seat 24 is fitted and fixed coaxially with the rotation axis O on the ground plane side (lower side in FIGS. 2 and 3) with respect to the large diameter portion 22 a of the balance stem 22. The swing seat 24 is formed by projecting a ring-shaped flange portion 24b outwardly in the radial direction on a cylindrical portion 24a that is externally fitted and fixed to the balance 22. The collar portion 24b is provided with a rock stone (not shown) for swinging the ankle 142.

  A balance wheel 23 is fixed to the large diameter portion 22 a of the balance stem 22. The balance wheel 23 is formed in a substantially arc shape so as to surround the balance stem 22 from the outer side in the radial direction about a half circumference, and two rim portions 25 arranged on both sides around the balance stem 22, An amid portion 26 that connects the balance stem 22 in the radial direction is provided.

The rim portion 25 has a bimetallic structure in which a low thermal expansion metal plate 27 and a high thermal expansion metal plate 28 made of materials having different thermal expansion coefficients are joined so as to overlap in the radial direction. Of the two metal plates 27 and 28, the low thermal expansion metal plate 27 located on the radially inner side, that is, on the inner peripheral surface side, is formed of a material having a low coefficient of thermal expansion, for example, silicon (Si). on the other hand,
The high thermal expansion metal plate 28 located on the radially outer side, that is, on the outer peripheral surface side, is formed of a high thermal expansion material having a higher thermal expansion coefficient than that of the low thermal expansion metal plate 27, for example, gold (Au).

The material of the low thermal expansion metal plate 27 is not limited to silicon, and various materials may be appropriately selected and used. Similarly, the material of the high thermal expansion metal plate 28 is not limited to gold, and various materials may be appropriately selected and used.
Here, one end of each rim portion 25 is set to a fixed end 25a to which the amidor portion 26 is connected, and the other end is set to a free end 25b. The two rim portions 25 are disposed such that the fixed ends 25a face each other with the balance 22 as the center.

  The amid portion 26 includes a fixing ring 29 that is externally fitted and fixed to the large diameter portion 22 a of the balance stem 22. Between the outer peripheral portion of the fixing ring 29 and the fixing end 25a of each rim portion 25, two arm portions 31 and 32 of a first arm portion 31 and a second arm portion 32 are provided, respectively. That is, each rim portion 25 is fixed to the balance 22 through the fixing ring 29, the first arm portion 31, and the second arm portion 32.

  Of the two rim portions 25, two arm portions 31 and 32 that connect one rim portion 25 and the fixing ring 29, and two arm portions 31 that connect the other rim portion 25 and the fixing ring 29. , 32 have the same structure, in the following description, only the two arm portions 31, 32 connected to one rim portion 25 and the fixing ring 29 will be described, and the other rim portion 25 and the fixing ring are described. The two arm portions 31 and 32 that connect to 29 are denoted by the same reference numerals, and description thereof is omitted.

  The two arm portions 31 and 32 are each formed in a substantially arc shape when viewed from the axial direction so as to extend about a half circumference, and the axial width H1 thereof is larger than the axial width H2 of the rim portion 25. Is also set to be shorter. The two arm portions 31 and 32 have a bimetallic structure in which two metal plates 33 and 34 made of materials having different thermal expansion coefficients are joined so as to overlap in the radial direction.

Of the two metal plates 33 and 34, the high thermal expansion metal plate 33 located on the inner peripheral surface side is formed of a material having a high thermal expansion coefficient, for example, gold (Au). On the other hand, the low thermal expansion metal plate 34 located on the outer peripheral surface side is formed of a material having a lower thermal expansion coefficient than that of the high thermal expansion metal plate 33, for example, silicon (Si).
The material of the high thermal expansion metal plate 33 is not limited to gold, and various materials may be appropriately selected and used. Similarly, the material of the low thermal expansion metal plate 34 is not limited to silicon, and various materials may be appropriately selected and used.

The two arm portions 31 and 32 formed in this way are arranged side by side along the radial direction, and are arranged so that the bending directions are staggered. Further, the two arm portions 31 and 32 are arranged so that their bending directions are in a horizontal direction orthogonal to the axial direction. As a result, the entire amid portion 26 is in a state where the intermediate portion protrudes from both end portions thereof.
Further, the respective radii of curvature R1a and R1b of the arm portions 31 and 32 are set to be substantially the same size, and set to be slightly larger than about ¼ of the curvature radius R2 of the rim portion 25. ing.

  More specifically, one end of the first arm portion 31 disposed on the radially inner side of the two arm portions 31 and 32 is connected to the outer peripheral portion of the fixing ring 29. The fixed end 31 b of 31 is set at a position opposite to the fixed end 25 a of the corresponding rim portion 25 with the balance 22 as the center. That is, the connecting portion 35 between the fixed end 31 b of the first arm portion 31 and the fixing ring 29 is set at a position opposite to the fixed end 25 a of the corresponding rim portion 25 with the balance 22 as the center. .

  The first arm portion 31 extends outward in the radial direction from the connecting portion 35 of the fixing ring 29 while curving toward the opposite side to the curving direction of the corresponding rim portion 25. And the free end 31a on the opposite side to the connection part 35 of the 1st arm part 31 is located in the approximate center between the rotating shaft O and the fixed end 25a of the rim | limb part 25 corresponding. One end of the second arm portion 32 is connected to the free end 31a of the first arm portion 31 via the connecting member 36 on the radially inner side, that is, on the inner peripheral surface side.

The connection member 36 is formed in a substantially rectangular cross section by the same material as the low thermal expansion metal plate 34 disposed on the outer peripheral surface side of the two arm portions 31 and 32.
Further, the second arm portion 32 disposed on the radially outer side than the first arm portion 31 is directed outward in the radial direction while being bent in the same direction as the bending direction of the corresponding rim portion 25 from the connection member 36. Is extended. And the fixed end 25a of the rim | limb part 25 is connected to the radial direction outer side, ie, the outer peripheral surface side, to the free end 32a on the opposite side to the connection member 36 of the 2nd arm part 32. FIG.

  Here, the position of the connection portion 35 between one end of the first arm portion 31 and the fixing ring 29 is set to a position opposite to the fixed end 25a of the corresponding rim portion 25 with the balance 22 as the center. As a result, the radius of curvature R1a of the first arm portion 31 can be set larger than when the connecting portion 35 is set at a position on the fixed end 25a side of the corresponding rim portion 25 of the fixing ring 29. In other words, the circumferential length of the first arm portion 31 is increased by setting the position of the connecting portion 35 to the position opposite to the fixed end 25a of the corresponding rim portion 25 with the balance 22 as the center. Can be set.

  Moreover, since the 1st arm part 31 and the 2nd arm part 32 are the states with which the internal peripheral surfaces of the edge part were respectively connected via the connection member 36, the position of the 2nd arm part 32 is made into the 1st. Compared with the case where the outer peripheral surfaces of the 1 arm part 31 and the 2nd arm part 32 are connected, it can be set as the shape offset in the radial direction inner side. In other words, a part of the first arm part 31 and a part of the second arm part 32 can be disposed so as to wrap in the radial direction. For this reason, the radius of curvature R1b of the second arm portion 32 can be set large, and as a result, the circumference of the second arm portion 32 can be set long.

(Rim part and manufacturing method of each arm part)
As a manufacturing method of the rim part 25, the first arm part 31, and the second arm part 32 configured as described above, for example, first, a predetermined mask (none of which is not shown) is used on a substrate such as a silicon wafer. Then, dry etching such as RIE (reactive ion etching) is performed to form slits corresponding to the rim portion 25, the first arm portion 31, and the second arm portion 32, respectively. And the high thermal expansion metal plates 28 and 33 (Au) are formed in this slit by electroforming.

  Subsequently, grooves for forming the low thermal expansion metal plates 27 and 34 are formed in a substrate (not shown). Specifically, a predetermined groove is formed again by performing etching such as RIE on a substrate (not shown) using a predetermined mask (both not shown). When the rim portion 25 is formed, the groove is formed along the inner peripheral surface of the high thermal expansion metal plate 28. On the other hand, when forming the 1st arm part 31 and the 2nd arm part 32, it forms along the outer peripheral surface of the high thermal expansion metal plate 33. FIG.

  Then, the low thermal expansion metal plates 27 and 34 (Si) are formed in the formed grooves. Thereafter, the electroformed portion protruding from the substrate (a part of the high thermal expansion metal plates 28 and 33) is removed, and the rim portion 25, the first arm portion 31, and the second arm portion are taken out from the substrate (not shown). 32 is completed.

In addition, the manufacturing method of the rim | limb part 25, the 1st arm part 31, and the 2nd arm part 32 is not restricted to the above-mentioned manufacturing method, Various manufacturing methods for forming a bimetal structure are employable. .
For example, low thermal expansion metal plates 27 and 34 (Si) corresponding to the curved shapes of the rim portion 25, the first arm portion 31, and the second arm portion 32 are prepared in advance. It is also possible to adopt a method of forming the high thermal expansion metal plates 28 and 33 (Au) on the surface. For film formation of the high thermal expansion metal plates 28 and 33, film formation methods such as sputtering, vapor deposition and electroless plating can be employed.

(Function of balance)
Next, based on FIG. 4, FIG. 5, the effect | action of the balance with hairspring 21 is demonstrated.
FIG. 4 is a diagram illustrating the operation of the balance with the temperature rising, and FIG. 5 is a diagram illustrating the operation of the balance with the temperature decreasing.
First, based on FIG. 4, the operation of the balance with the temperature rise will be described.
As shown in the figure, the rim portion 25 has a low thermal expansion metal plate 27 disposed on the inner peripheral surface side and a high thermal expansion metal plate 28 disposed on the outer peripheral surface side. The outer peripheral surface expands more thermally than the peripheral surface. As a result, the free end 25b side of the rim portion 25 is displaced toward the radially inner side.

  Further, in the first arm portion 31 and the second arm portion 32 constituting the amid portion 26, the high thermal expansion metal plate 33 is disposed on the inner peripheral surface side, while the low thermal expansion metal plate 34 is disposed on the outer peripheral surface side. Has been. For this reason, as the temperature rises, in the first arm portion 31 and the second arm portion 32, the free ends 31 a and 32 a are displaced outward in the radial direction.

  At this time, the curvature radius R1a of the first arm portion 31 and the curvature radius R1b of the second arm portion 32 are slightly larger than about ¼ with respect to the curvature radius R2 of the rim portion 25, respectively. The amount of displacement of 31 and 32 is smaller than the amount of displacement of the rim portion 25. Furthermore, since the connection member 36 that connects the first arm portion 31 and the second arm portion 32 is formed by the low thermal expansion metal plate 34 of each arm portion 31, 32, the thermal expansion hardly occurs. For this reason, the second arm portion 32 is not displaced radially inward.

  Thus, the amid portion 26 is deformed so as to extend slightly toward the radially outer side. Accordingly, the fixed end 25a of the rim portion 25 is displaced toward the outer side in the radial direction while being slightly displaced toward the side opposite to the free end 25b in the circumferential direction. As a result, the free end 25b of the rim portion 25 is further displaced radially inward (see arrow Y1 in FIG. 4). The balance wheel 23 as a whole is in a state as indicated by a two-dot chain line in FIG.

Then, based on FIG. 5, the effect | action of the balance 21 at the time of temperature fall is demonstrated.
Here, when the temperature falls, the displacement is opposite to that when the temperature rises. That is, when the temperature is lowered, the outer peripheral surface side of the rim portion 25 contracts more than the inner peripheral surface side. For this reason, the free end 25b side of the rim | limb part 25 is displaced toward a radial direction outer side. On the other hand, as for the 1st arm part 31 and the 2nd arm part 32, each free end 31a, 32a displaces toward radial inside.

  Thus, the amid portion 26 is deformed so as to be slightly degenerated toward the radially inner side. Thereby, the fixed end 25a of the rim portion 25 is displaced toward the inner side in the radial direction while being slightly displaced toward the free end 25b in the circumferential direction. As a result, the free end 25b of the rim portion 25 is further displaced radially outward (see arrow Y2 in FIG. 5). The balance wheel 23 as a whole is in a state as indicated by a two-dot chain line in FIG.

Here, based on FIG. 6 and FIG. 7, a comparison is made between the displacement amount associated with the temperature change of the rim portion 25 in the first embodiment and the displacement amount associated with the temperature change of the conventional rim portion 720.
6 and 7, in order to compare the first embodiment with the conventional one, the low thermal expansion metal plate 27 and the high thermal expansion metal plate 28 constituting the rim portion 25, the arm portions 31, The materials used for the low thermal expansion metal plate 34 and the high thermal expansion metal plate 33 constituting the base plate 32 are the same as those used in the prior art. That is, the material used for the low thermal expansion metal plates 27 and 34 is Invar, and the material used for the high thermal expansion metal plates 28 and 33 is brass. 6 and 7, the balance wheel 23 of the first embodiment is indicated by a solid line, and the conventional balance wheel 712 is indicated by a two-dot chain line.

FIG. 6 is an explanatory diagram comparing displacement amounts of the rim portion in the first embodiment and the conventional rim portion when the temperature rises.
As shown in the figure, in the first embodiment, as the temperature rises, the amid portion 26 is displaced so as to extend slightly outward in the radial direction, so that the free end 25b of the rim portion 25 is It is displaced radially inward from the free end 720b of the conventional rim portion 720.

FIG. 7 is an explanatory diagram comparing the displacement amounts of the rim portion in the first embodiment and the conventional rim portion when the temperature drops.
As shown in the figure, in the present embodiment, the amid portion 26 is displaced so that the amid portion 26 is slightly retracted radially inward as the temperature decreases. 25b is displaced radially outward from the free end 720b of the conventional rim portion 720.

  Here, as shown in FIG. 6, when the temperature rises, the position of the fixed end 25 a of the rim portion 25 is simply shifted radially outward as compared with the conventional one, while the position of the free end 25 b of the rim portion 25. However, it can be considered that it is shifted inward in the radial direction as compared with the conventional case. However, most of the rim portion 25 as a whole is displaced radially inward from the conventional rim portion 720. For this reason, the moment of inertia is reduced as compared with the conventional balance 700.

  On the other hand, as shown in FIG. 7, when the temperature is lowered, the position of the fixed end 25a of the rim portion 25 is simply shifted radially inward as compared with the conventional case, while the position of the free end 25b of the rim portion 25 is It can also be considered that it has just shifted to the outside in the radial direction compared to the conventional case. However, most of the rim portion 25 as a whole is in a state of being displaced radially outward from the conventional rim portion 720. For this reason, the moment of inertia increases as compared with the conventional balance 700.

This will be described in more detail with reference to FIG.
FIG. 8 is a graph comparing the change rate of the moment of inertia of the balance with the vertical axis as the rate of change of the moment of inertia of the balance and the horizontal axis as the temperature.
As shown in the figure, it can be confirmed that the inertia moment of the balance 21 of the first embodiment is smaller than the inertia moment of the conventional balance 700 in the temperature rise region. It can be confirmed that the difference in moment of inertia increases as the temperature increases.
On the other hand, it can be confirmed that the inertia moment of the balance 21 of the first embodiment is larger than the inertia moment of the conventional balance 700 in the temperature drop region. It can be confirmed that the difference in moment of inertia increases as the temperature increases.

(effect)
Therefore, according to the above-described first embodiment, both the rim portion 25 and the amider portion 26 can be displaced with a temperature change. That is, when the same material as the conventional material is used for the bimetal structure, the amount of displacement by which the rim portion 25 moves toward the inside in the radial direction when the temperature rises can be made larger than that of the conventional material. For this reason, the difference of the thermal expansion coefficient of the two materials which comprise the rim | limb part 25 and the amider part 26 can be set smaller than before. As a result, it is possible to increase the choice of materials to be selected for the bimetal structure. That is, for example, silicon (Si) can be used as the low thermal expansion metal plates 27 and 34, while gold (Au) can be used as the high thermal expansion metal plates 28 and 33.
For this reason, it is not necessary to join two metal plates (invar and brass) by brazing as in the prior art, and for example, high-precision processing such as RIE processing and electroforming can be performed as in the above-described manufacturing method. A manufacturing method can be adopted. Therefore, the processing accuracy of the balance with hairspring 21 can be improved as compared with the prior art.

Further, when adopting a bimetal structure like the rim portion 25 and the arm portions 31 and 32 as in the prior art, a non-magnetic material other than Invar can be used as the material, so that the rim portion 25 is affected by the influence of magnetism. It is possible to prevent the amount of displacement of the lens from becoming small. For this reason, it is possible to stably keep the temperature dependence of the vibration period of the balance with hairspring 21 low.
Furthermore, since the displacement amount of the rim portion 25 accompanying the temperature change can be made larger than before, the rim portion 25 can be thickened accordingly. For this reason, the rigidity of the rim | limb part 25 can be improved and the assembly | attachment property of the balance with hairspring 21 can be improved.

  Then, the amid portion 26 includes a fixing ring 29, a first arm portion 31 and a second arm portion 32 provided between the outer peripheral portion of the fixing ring 29 and the fixing end 25a of each rim portion 25, A connecting member 36 that connects the first arm portion 31 and the second arm portion 32 is configured, and the arm portion 26 is displaced by displacing each of the arm portions 31 and 32 with a temperature change. For this reason, it is possible to efficiently increase the amount of displacement of the entire amid portion 26 while suppressing an increase in the size of the amid portion 26 as compared with the case where the entire amid portion 26 is curved and displaced.

  Moreover, while setting the position of the connection part 35 of the end of the 1st arm part 31 and the fixing ring 29 to the fixed end 25a of the corresponding rim | limb part 25 on the opposite side centering on the balance stem 22, The first arm portion 31 and the second arm portion 32 are arranged such that the inner peripheral surfaces of the end portions are connected to each other via a connecting member 36 so that both the 31 and 32 are wrapped in the radial direction. For this reason, the perimeter of each arm part 31 and 32 can be set as long as possible, and the amount of displacement of the entire amidor part 26 can be increased more reliably by this amount.

  Further, since the connection member 36 that connects the first arm portion 31 and the second arm portion 32 is formed by the low thermal expansion metal plate 34 of each arm portion 31 and 32, the thermal expansion hardly occurs. For this reason, it can suppress that the relative position of the 1st arm part 31 and the 2nd arm part 32 changes, and the displacement amount of the whole amider part 26 can be enlarged effectively.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a plan view of the balance with the balance according to the second embodiment. The same aspects as those in the first embodiment will be described with the same reference numerals (the same applies to the following embodiments).
In the second embodiment, the complete 1a of the mechanical timepiece 1 has a movement 100 housed in a timepiece case 3, and the movement 100 has a dial 2 having a scale 3a indicating information about time, and a time. The movement 100 includes a barrel wheel 120, a second wheel 124, and a third wheel 126 that constitute a front train wheel. The hour hand 4a, the minute hand 4b that indicates the minute, and the needle 4 that includes the second hand 4c that indicates the second are provided. And the fourth wheel & pinion 128 and the escapement / regulation mechanism 20 for controlling the rotation of the front train wheel. The escapement / regulation mechanism 20 includes an escape wheel 130, an ankle 142 and the balance with hairspring 121 (see FIG. 1 above), the balance with hairspring 121 is supported so as to be rotatable around the rotation axis O, and the balance wheel fixed to the balance with the balance 22 23, not shown The balance wheel has a mainspring 23. The balance wheel 23 is formed in a substantially arc shape so as to surround the balance stem 22 from the outer side in the radial direction about a half circumference, and two rims arranged on both sides of the balance stem 22 as a center. A fixing ring that is externally fixed to the large-diameter portion 22a of the balance stem 22 in that it includes a portion 25 and an amid portion 26 that connects the rim portion 25 and the balance stem 22 in the radial direction. 29, and a first arm portion 31 and a second arm portion 32 provided between the outer peripheral portion of the fixing ring 29 and the fixing end 25a of each rim portion 25. These first arm portions The basic configuration such as the point 31 and the second arm portion 32 are joined via a connection member 36 (see FIG. 9 above) is the same as that of the first embodiment described above (the following embodiments). The same applies to.

Here, the difference between the second embodiment and the first embodiment is that the outer peripheral surface of the rim portion 25 of the second embodiment is provided with one large weight portion 41 and six small weight portions 42. In contrast, the rim portion 25 of the first embodiment is not provided with the large weight portion 41 and the small weight portion 42.
As shown in detail in FIG. 9, the mass portion 41 is provided on the free end 25 b side of the rim portion 25. Further, the six small weight portions 42 are provided at arbitrary positions between the large weight portion 41 and the fixed end 25 a of the rim portion 25.

The attachment position of the small weight part 42 will be described more specifically.
Here, the position of the approximate center in the circumferential direction of the rim portion 25 is P1. A range from the position P1 to the fixed end 25a of the rim portion 25 is a fixed end area W1, and a range from the position P1 to the free end 25b of the rim portion 25 is a free end area W2. At this time, the six small weight portions 42 have a large weight portion 41 provided in the free end side area W2 and a small weight portion, rather than the total weight of the small weight portions 42 provided in the fixed end side area W1. It arrange | positions so that the total weight of 42 may become large.

That is, three small weight portions 42 are arranged in each of the fixed end side area W1 and the free end side area W2. Furthermore, one of the three small weight portions 42 disposed in the fixed end side area W1 is disposed closer to the position P1.
Here, the displacement amount accompanying the temperature change of the rim portion 25 increases as it goes to the free end 25b (see FIG. 4). For this reason, the total weight of the large weight part 41 and the small weight part 42 provided in the free end side area W2 is larger than the total weight of the small weight part 42 provided in the fixed end side area W1. Therefore, the amount of change in the moment of inertia accompanying the displacement of the rim portion 25 can be increased.

  Therefore, according to the second embodiment described above, in addition to the same effects as those of the first embodiment described above, it is possible to more effectively suppress the temperature dependence of the vibration period of the balance with hairspring 21. Further, as described in the first embodiment, since the processing accuracy of the balance with hairspring 21 can be improved as compared with the conventional one, each weight portion 41 is provided in order to suppress the temperature dependence of the vibration cycle of the balance with hairspring 21 more effectively. , 42 can be easily adjusted.

  In the second embodiment described above, the case where one large weight portion 41 and six small weight portions 42 are provided on the outer peripheral surface of the rim portion 25 has been described. However, the numbers of the large weight portions 41 and the small weight portions 42 are not particularly limited, and can be set to an arbitrary number. At this time, it is only necessary to set the total weight of the weight portion provided in the free end area W2 to be larger than the total weight of the weight portion provided in the fixed end area W1.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 10 is a plan view of the balance with the balance according to the third embodiment.
As shown in the figure, the difference between the third embodiment and the first embodiment is that, in the balance 221 of the third embodiment, the shape of the first arm portion 231 constituting the amid portion 226 is the first embodiment. This is in a point different from the shape of the first arm portion 31 in the form.

  More specifically, the first arm portion 231 in the third embodiment is formed in a substantially U shape when viewed from the axial direction, and includes an arm main body 251 formed in a substantially arc shape, and the arm main body 251. A pair of extending portions 252 and 252 extending from both ends so as to be parallel to each other are integrally formed. The high thermal expansion metal plate 233 is disposed on the inner peripheral surface side, while the low thermal expansion metal plate 234 is disposed on the outer peripheral surface side.

The arm main body 251 is formed in substantially the same shape as the first arm portion 31 and the second arm portion 32 of the first embodiment described above. One end of the pair of extending portions 252 and 252 is a connecting portion 35 with the fixing ring 29. Furthermore, the inner peripheral surface side of the other end portion of the pair of extending portions 252 and 252 is connected to one end of the second arm portion 32 via the connection member 36.
In the third embodiment, the free end 25b of the rim portion 25 is provided with one weight portion 243 on the outer peripheral surface side. However, the present invention is not limited to this, and the weight portion 243 is not provided. Also good.

Therefore, according to the above-described third embodiment, the same effects as those of the above-described first embodiment can be obtained.
The first arm portion 231 includes an arm body 251 having substantially the same shape as the first arm portion 31 and the second arm portion 32, and a pair of extending portions 252 extending from both ends of the arm body 251. 25, the displacement amount between the pair of extending portions 252 and 252 is larger than the displacement amount between the both end portions of the first arm portion 31 of the first embodiment described above. For this reason, the amount of displacement of the amid portion 226 accompanying the temperature change can be made larger than that in the first embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 11 is a plan view of the balance in the fourth embodiment, and FIG. 12 is a longitudinal sectional view of the balance in the fourth embodiment.
As shown in the figure, the difference between the fourth embodiment and the first embodiment is that the balance with the balance 321 of the fourth embodiment is located on the outer side in the radial direction of the balance wheel 23 having the rim portion 25 and the amid portion 26. In contrast to the annular outer balance wheel 61 formed so as to surround the balance wheel 23, the balance wheel 61 of the first embodiment is not provided with the outer balance wheel 61. is there.

The outer balance wheel 61 is arranged so as to be coaxial with the balance stem 22. Further, the axial width H3 of the outer balance wheel 61 is set to be longer than the axial width H2 of the rim portion 25. An outer balance wheel 61 is attached to the balance stem 22 via an outer amid portion 62.
The outer amid portion 62 is formed in a band shape along the radial direction, and is disposed on the main plate side (not shown, lower side in FIG. 12) of the balance wheel 23.

  Under such a configuration, the rim portion 25 and the amid portion 26 constituting the balance wheel 23 are displaced with the temperature change, while the outer balance wheel 61 is hardly displaced. For this reason, the amount of change in the amount of displacement is the same as in the first embodiment described above, but the moment of inertia of the balance 321 can be increased because the outer balance wheel 61 is provided.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS.
FIG. 13 is a plan view of the balance in the fifth embodiment, and FIG. 14 is a longitudinal sectional view of the balance in the fifth embodiment.
As shown in the figure, the difference between the fifth embodiment and the first embodiment is that a balance 421 of the fifth embodiment has a weight in addition to a balance wheel 23 having a rim portion 25 and an amid portion 26. Whereas the plate 71 is provided, the balance plate 71 of the first embodiment is not provided with the weight plate 71.

  The weight plate 71 has a strip-shaped plate body 72 extending along the radial direction. The balance stem 22 is attached to the center of the plate body 72 in the longitudinal direction. The length of the plate body 72 is set to a length that protrudes radially outward from the balance wheel 23. At both ends in the longitudinal direction of the plate body 72, weight blocks 73 are respectively provided on the balance receiving side (not shown) (the front side in FIG. 13 and the upper side in FIG. 14).

  Therefore, according to the above-described fifth embodiment, the weight moment of the balance 421 can be increased by the weight block 73, and the same effect as in the above-described fourth embodiment can be obtained.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIG.
FIG. 15 is a plan view of the balance with the balance according to the sixth embodiment.
As shown in the figure, the difference between the sixth embodiment and the first embodiment is that, in the balance 521 of the sixth embodiment, the arrangement angles of the arm portions 31 and 32 constituting the amida portion 526 are This is in a point different from the arrangement angle of the arm portions 31 and 32 constituting the amid portion 26 of the embodiment.

  More specifically, the amid portion 526 includes a fixing ring 29, a first arm portion 31 and a second arm portion 32 provided between the outer peripheral portion of the fixing ring 29 and the fixing end 25 a of each rim portion 25. The connection member 36 that connects the free end 31 a of the first arm portion 31 and one end of the second arm portion 32 is provided. Each arm part 31 and 32 is arrange | positioned along with radial direction, and is arrange | positioned so that a curve direction may become alternate.

Here, although each arm part 31 and 32 of 1st Embodiment is arrange | positioned so that these curve directions may turn into the horizontal direction orthogonal to an axial direction, each arm part 31 and 32 of 6th Embodiment is These bending directions are arranged in a state inclined by an angle α with respect to the horizontal direction.
Even in this case, the same effects as those of the first embodiment described above can be obtained.

(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described with reference to FIG.
FIG. 16 is a plan view of a balance with a balance according to the seventh embodiment.
As shown in the figure, the difference between the seventh embodiment and the first embodiment is that the balance portion 26 of the balance 21 in the first embodiment is the outer peripheral portion of the fixing ring 29 and the fixed end of each rim portion 25. While the two arm portions 31 and 32 of the first arm portion 31 and the second arm portion 32 are provided between the arm portion 626 of the balance 721 in the seventh embodiment, The arm portion 631 is provided between the outer peripheral portion of the fixing ring 29 and the fixed end 25a of each rim portion 25.

The arm portion 631 has a bimetallic structure in which two metal plates 633 and 634 made of materials having different thermal expansion coefficients are joined so as to overlap in the radial direction. In addition, the structure of these metal plates 633 and 634 is the same as that of the metal plates 33 and 34 in 1st Embodiment.
Further, the arm portion 631 is disposed so that the bending direction is a horizontal direction orthogonal to the axial direction. Further, the curvature radius R3 of the arm portion 631 is set to be slightly larger than about ½ of the curvature radius R2 of the rim portion 25.

  Further, the fixed end 631b of the arm portion 631 is set to a position opposite to the fixed end 25a of the corresponding rim portion 25 with the balance 22 as the center. That is, the connecting portion 35 between the fixed end 631b of the arm portion 631 and the fixing ring 29 is set at a position opposite to the fixed end 25a of the corresponding rim portion 25 with the balance 22 as the center.

Furthermore, the arm portion 631 extends outward in the radial direction from the connecting portion 35 of the fixing ring 29 while being bent in the same direction as the bending direction of the corresponding rim portion 25. The free end 631a opposite to the connection portion 35 of the arm portion 631 is connected to the fixed end 25a of the corresponding rim portion 25.
Even in this case, the same effects as those of the first embodiment described above can be obtained.

(Eighth embodiment)
Next, an eighth embodiment of the present invention will be described with reference to FIG.
FIG. 17 is a plan view of the balance with the balance according to the eighth embodiment.
As shown in the figure, the difference between the eighth embodiment and the first embodiment is that the amid portion 26 of the balance 21 in the first embodiment is formed by arm portions 31 and 32 formed in a substantially arc shape. However, the amid portion 726 of the balance with hairspring 721 in the eighth embodiment is not formed in a substantially arc shape.

More specifically, the amid portion 726 has a fixing ring 29, and a first bar 731 extending along the tangential direction is connected to the outer peripheral portion of the fixing ring 29 and connected to the tangential direction. . The first bar 731 has a bimetallic structure in which two metal plates 733 and 734 made of materials having different thermal expansion coefficients are joined so as to overlap in the radial direction.
In addition, the structure of these metal plates 733 and 734 is the same as that of the metal plates 33 and 34 in 1st Embodiment. That is, of the two metal plates 733 and 734, the high thermal expansion metal plate 733 is disposed on the radially inner side, that is, on the fixing ring 29 side. On the other hand, of the two metal plates 733 and 734, the low thermal expansion metal plate 734 is arranged on the outer side in the radial direction, that is, on the side opposite to the fixing ring 29.

  A second bar 732 having the same configuration as the first bar 731 is disposed on the outer side in the radial direction from the first bar 731 so as to be substantially parallel to the first bar 731. Of the two metal plates 733 and 734, the second bar 732 also has the high thermal expansion metal plate 733 arranged on the inner side in the radial direction, and the high thermal expansion metal plate 733 is opposed to the low expansion metal plate 734 of the first bar 731. It is in the state.

  A connection bar 736 is provided between the free end 731 a of the first bar 731 and one end of the second bar 732 so as to straddle both 731 and 732. The connection bar 736 has a substantially rectangular cross section made of the same material as the low thermal expansion metal plate 734 disposed on the radially outer side of the two bars 731 and 732. Furthermore, a connection bar 737 is provided between the free end 732 a of the second bar 732 opposite to the connection bar 736 and the fixed end 25 a of the rim portion 25 so as to straddle both 732 and 25. The connection bar 737 is also formed in a substantially rectangular cross section with the same material as the low thermal expansion metal plate 734 disposed on the radially outer side of the two bars 731 and 732.

Under such a configuration, the entire amid portion 726 is in a state in which the intermediate portion protrudes from both ends thereof.
Therefore, according to the above-described eighth embodiment, the same effects as those of the above-described first embodiment can be obtained.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in the first embodiment, the second embodiment, the fourth embodiment, the fifth embodiment, and the sixth embodiment described above, between the outer peripheral portion of the fixing ring 29 and the fixed end 25a of each rim portion 25. The case where the two arm portions 31 and 32 of the first arm portion 31 and the second arm portion 32 are provided has been described. In the third embodiment described above, the two arm portions 231 of the first arm portion 231 and the second arm portion 32 are provided between the outer peripheral portion of the fixing ring 29 and the fixing end 25a of each rim portion 25, respectively. , 32 has been described. Further, in the seventh embodiment described above, the case where one arm portion 631 is provided between the outer peripheral portion of the fixing ring 29 and the fixed end 25a of each rim portion 25 has been described. However, the number of the arm portions 31, 32, 231, 631 disposed between the outer peripheral portion of the fixing ring 29 and the fixed end 25a of each rim portion 25 is not limited to one or two, but 3 There may be more than one.

1 Mechanical clock (clock)
20 Escapement / regulation mechanism 21, 121, 221, 321, 421, 521, 621, 721 balance 22 balance stem 25 rim portion 25a fixed end (connection end)
25b Free end 26, 226, 526, 626, 726 Amida portion 27, 34, 634, 734 Low thermal expansion metal plate (material)
28, 33, 633, 733 High thermal expansion metal plate (material)
29 Fixing rings 31 and 231 First arm part (arc-shaped part, arm part)
31a, 631a, 731a Free end 31b, 631b, 731b Fixed end 32 Second arm part (arc-shaped part, arm part)
35 connection part 36 connection member 41 large weight part (weight part)
42 Small weight (weight)
243, 343, 443 Weight 100 movement (watch movement)
120 incense wheel 124 second wheel (wheel train)
126 Third wheel (wheel train)
128 Number 4 (Wheel train)
631 Arm portion 736, 737 Connection bar W1 Fixed end side area W2 Free end side area

Claims (9)

Tenshin,
A balance comprising at least two rim portions formed in an arc shape so as to surround the balance stem from the outside in the radial direction, and a balance wheel having an amid portion for connecting one end of the rim portion to the outer peripheral portion of the balance stem. There,
The rim portion is formed by laminating two materials having different thermal expansion coefficients in the radial direction,
The amid portion is formed by laminating at least a portion of two materials having different coefficients of thermal expansion in the radial direction, and is formed such that an intermediate portion protrudes from both end portions of the amid portion,
The balance with hairspring, wherein a free end of the rim portion and a connection end of the amid portion with the rim portion are deformed in a direction opposite to each other according to a temperature change. The rim portion is set so that the thermal expansion coefficient of the material on the radially outer side of the rim portion is larger than the material on the radially inner side of the rim portion,
The amid portion is formed so as to have an arc-shaped portion curved at least partially, and at least the arc-shaped portion is formed by laminating two materials having different thermal expansion coefficients in the radial direction, and the arc-shaped portion The balance according to claim 1, wherein the balance is set so that the thermal expansion coefficient of the material radially outside the arc-shaped portion is smaller than the material radially inside. The rim portion is provided with at least one weight portion,
The total weight of the weight portion provided on the free end side from the longitudinal center of the rim portion is set to be larger than the total weight of the weight portion provided on the fixed end side. The balance with hairspring according to claim 1 or 2.   The position of the fixed end on the balance side in the amid portion is located on the opposite side from the fixed end of the corresponding rim portion with the balance as a center. The balance of any one of items 3. The amid portion has a plurality of arm portions formed in an arc shape by laminating two materials having different thermal expansion coefficients in the radial direction,
The balance according to any one of claims 1 to 4, wherein end portions on the inner peripheral surface side of each arm portion are connected to each other via a connecting member.   The balance according to claim 5, wherein the connecting member is formed of a material having a low coefficient of thermal expansion among two materials having different coefficients of thermal expansion. 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;
A timepiece movement comprising the balance according to claim 1, which adjusts the speed of the escapement mechanism.   A timepiece comprising the timepiece movement according to claim 7. Tenshin is supported rotatably,
A balance wheel having an arcuate rim portion that surrounds the balance spring from the outside in the radial direction and is coaxially arranged with the balance stem, and an amid portion that connects one end of the rim portion and the outer peripheral portion of the balance scale in the radial direction. A method for producing a balance comprising:
The rim part is formed by arranging two materials having different coefficients of thermal expansion and patterning them in an arc shape,
Forming the amid portion so as to have an arc-shaped portion at least partially;
A method for manufacturing a balance with the arc-shaped portion formed by arranging two materials having different coefficients of thermal expansion and patterning them in an arc shape.

Images