Balance-spring mechanism and manufacturing method therefor, movement, mechanical timepiece

Abstract

This invention provides a balance wheel and hairspring mechanism and its manufacturing method, movement, and mechanical watch, enabling the easy manufacture of a metal hairspring. The balance wheel and hairspring mechanism disclosed herein comprises: a balance shaft rotatably supported on a support member; an inner stud fixed to the balance shaft; and a metal hairspring fixed to the inner stud, the hairspring having: an inner end portion fixed to the inner stud; a first winding portion continuously formed from the inner end portion along a Grossman shape; and a second winding portion continuously formed from the first winding portion along an Archimedean curve. The inner stud has: a fixing portion fixing the inner end portion of the hairspring; and an outer peripheral shape portion disposed at a position opposite to the inner surface of the first winding portion for forming the first winding portion into a Grossman shape.

Description

Technical Field

[0001] This invention relates to a balance wheel and hairspring mechanism, a movement, a mechanical watch, and a method for manufacturing the balance wheel and hairspring mechanism. Background Technology

[0002] Patent document 1 discloses a method for manufacturing a speed regulator hairspring in a mechanical clock by micro-machining amorphous materials such as silicon wafers or crystalline materials.

[0003] In Patent Document 1, this allows the hairspring to be shaped like a Grossmann, thereby improving isochronism.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-15534

[0005] However, in Patent Document 1, in order to manufacture a metal hairspring, LIGA technology is required to form a mold corresponding to the desired profile of the hairspring. Therefore, Patent Document 1 presents a problem where it is not easy to manufacture a metal hairspring. Summary of the Invention

[0006] The balance wheel and hairspring mechanism disclosed herein comprises: a balance shaft rotatably supported on a support member; an inner stud fixed to the balance shaft; and a metal hairspring fixed to the inner stud, the hairspring having: an inner end portion fixed to the inner stud; a first winding portion continuously formed from the inner end portion along a Grossman-type shape; and a second winding portion continuously formed from the first winding portion along an Archimedean curve, the inner stud having: a fixing portion fixing the inner end portion of the hairspring; and an outer peripheral shape portion disposed at a position opposite to the inner surface of the first winding portion for forming the first winding portion into a Grossman-type shape.

[0007] The movement disclosed herein has the aforementioned balance wheel and hairspring mechanism.

[0008] The mechanical clock disclosed herein has the aforementioned movement.

[0009] The method for manufacturing the balance wheel and hairspring mechanism disclosed herein is a method for manufacturing a balance wheel and hairspring mechanism having the following parts: a balance shaft, which is rotatably supported on a support member; an inner stud, which is fixed to the balance shaft; and a metal hairspring, the inner end of which is fixed to the inner stud. In this method for manufacturing the balance wheel and hairspring mechanism, the following steps are included: forming the hairspring along an Archimedean curve; fixing the inner end of the hairspring to the inner stud; and using the outer peripheral shape of the inner stud to form the section of the hairspring from the inner end to a predetermined length into a Grossman-type shape. Attached Figure Description

[0010] Figure 1 This is a front view of a mechanical clock representing one implementation.

[0011] Figure 2 This is a front view showing the movement of the described embodiment.

[0012] Figure 3 This is a front view showing the balance wheel and hairspring mechanism of the described embodiment.

[0013] Figure 4 It is Figure 3 A magnified portion of the main view.

[0014] Figure 5 This is a cross-sectional view showing the internal pile of the described embodiment.

[0015] Figure 6 This is a perspective view of the inner pile of the described embodiment.

[0016] Figure 7 This is a front view showing the manufacturing method of the hairspring.

[0017] Figure 8 This is a front view showing the manufacturing method of the hairspring.

[0018] Figure 9 This is a cross-sectional view showing the manufacturing process of the hairspring.

[0019] Figure 10 This is a front view showing the manufacturing method of the hairspring.

[0020] Figure 11 This is a front view showing the manufacturing method of the hairspring.

[0021] Label Explanation

[0022] 1: Mechanical watch; 2: Outer case; 3: Dial; 3A: Date window; 4A: Hour hand; 4B: Minute hand; 4C: Second hand; 5: Power reserve hand; 6: Date wheel; 7: Crown; 10: Movement; 11: Case back; 12: First bridge; 13: Balance wheel and hairspring mechanism bridge; 21: Barrel wheel; 23: Third wheel; 24: Fourth wheel; 25: Escapement wheel; 26: Escapement fork; 27: Regulator; 30: Manual winding mechanism; 31: Crown; 32: Clutch wheel; 33: Balance wheel; 40: Small steel wheel; 51: First intermediate wheel; 52: Second intermediate wheel; 2. Intermediate wheel; 60: Large steel wheel; 70: Hairspring; 71: Inner end; 72: First winding part; 73: Second winding part; 74: Outer end; 170: Hairspring material; 400: Balance wheel and hairspring mechanism; 410: Balance shaft; 420: Balance wheel; 440: Inner stud; 441: Inner stud body; 442: Fixing part; 443: Outer peripheral shape part; 444: Balance shaft insertion hole; 445: Center of gravity adjustment part; 446: Support part; 4411: Thin-walled part; 4421: First abutment part; 4422: Second abutment part; 4423: Third abutment part. Detailed Implementation

[0023] [Implementation Method]

[0024] Hereinafter, a mechanical clock 1 according to one embodiment of the present disclosure will be described based on the accompanying drawings.

[0025] Figure 1 This is the front view of mechanical clock 1. Figure 2 This is the front view of the movement 10.

[0026] like Figure 1 , 2 As shown, the mechanical watch 1 is a wristwatch worn on the user's wrist, and has a cylindrical outer casing 2. A dial 3 is arranged on the inner circumference of the outer casing 2. The front opening of the outer casing 2 is closed by a glass cover, and the back opening is closed by a back cover.

[0027] In addition, the mechanical clock 1 includes: a movement 10 housed within an outer case 2; an hour hand 4A, a minute hand 4B, and a second hand 4C that display time information; and a power reserve hand 5 that indicates the duration of the mainspring (not shown) provided in the movement 10.

[0028] The hour hand 4A, minute hand 4B, second hand 4C, and power reserve hand 5 are mounted on the pointer axis of the movement 10 and are driven by the movement 10.

[0029] A calendar window 3A is provided on the dial 3, through which the date wheel 6 can be seen.

[0030] A crown 7 is provided on the side of the outer casing 2. The crown 7 can be pulled out 2 levels from the 0 level position, which is pressed in toward the center of the mechanical clock 1.

[0031] If the crown 7 is rotated to position 0, the mainspring can be wound, as described later. In conjunction with the winding of the mainspring, the power reserve hand 5 moves. The mechanical clock 1 of this embodiment can ensure a duration of approximately 40 hours when the mainspring is fully wound. If the crown 7 is pulled to position 1 and rotated, the date wheel 6 can be moved to align with the date. If the crown 7 is pulled to position 2, the second hand 4C stops; if the crown 7 is rotated in position 2, the hour hand 4A and minute hand 4B can be moved to align with the time.

[0032] [Motion]

[0033] The movement 10 includes a base plate 11, a first bridge 12, and a balance wheel and hairspring mechanism bridge 13. Between the base plate 11 and the first bridge 12 are arranged a barrel wheel 21 (containing the mainspring), a second wheel, a third wheel 23, a fourth wheel (not shown), and an escapement wheel 25. Additionally, between the base plate 11 and the balance wheel and hairspring mechanism bridge 13 are an escapement fork 26, a regulator 27, etc. Furthermore, in this embodiment, the regulator 27 includes a balance wheel and hairspring mechanism 400.

[0034] [Manual top-of-the-line mechanism]

[0035] The manual winding mechanism 30 includes a stem 31 rotatably supported on a first plate 12, a clutch wheel 32, a vertical wheel 33, a small steel wheel 40, a first intermediate wheel 51, and a second intermediate wheel 52. It transmits rotational power from the crown 7 to the mainspring wheel 60, causing the mainspring to wind by rotating the mainspring wheel 60 and the barrel shaft. The small steel wheel 40 consists of a first small steel wheel 41 that meshes with the vertical wheel 33, and a second small steel wheel 42 that rotates integrally with the first small steel wheel 41 and meshes with the first intermediate wheel 51.

[0036] Balance wheel and hairspring mechanism

[0037] Figure 3 This is the front view of the balance wheel and hairspring mechanism 400.

[0038] like Figure 3 As shown, the balance wheel and hairspring mechanism 400 is configured to include a balance shaft 410, a balance wheel 420, an inner stud 440, and a hairspring 70.

[0039] The balance shaft 410 is rotatably supported on the base plate 11 and the balance wheel and hairspring mechanism clamp 13. Furthermore, the base plate 11 and the balance wheel and hairspring mechanism clamp 13 are an example of the support components of this disclosure.

[0040] A balance wheel 420 and an inner stud 440 are fixed to the balance shaft 410, and they rotate as a single unit. The inner end 71 of the hairspring 70 is fixed to the inner stud 440, and the outer end 74 is fixed to the outer stud (not shown). The outer stud is fixed to the balance wheel and hairspring mechanism clamp 13.

[0041] Furthermore, in this balance wheel and hairspring mechanism 400, if the balance wheel 420 rotates about the balance axis 410, the inner stud 440 also rotates accordingly. Therefore, the force of the hairspring 70 acts on the balance wheel 420. If this force balances the inertial force of the balance wheel 420, the rotation of the balance wheel 420 stops. Through the force of the hairspring 70, the balance wheel 420 rotates in the opposite direction. That is, the balance wheel 420 oscillates repeatedly about the balance axis 410.

[0042] [gossamer]

[0043] Figure 4 It is Figure 3 A magnified top view of a portion of the image.

[0044] like Figure 3 , 4 As shown, the hairspring 70 is formed of a metal plate-shaped elastic material. Specifically, it is formed of a plate-shaped elastic material such as Coeriva alloy, which is an alloy containing Cr, Ni, Co, etc.

[0045] In this embodiment, the hairspring 70 has an inner end portion 71, a first winding portion 72, a second winding portion 73, and an outer end portion 74.

[0046] The inner end 71 is the part that is inserted into and fixed to the fixing part 442 of the inner pile 440, which will be described later.

[0047] The first winding portion 72 is formed continuously from the inner end portion 71. In this embodiment, when viewed from above in the axial direction of the swing shaft 410, the first winding portion 72 is formed along a Grossman-type shape.

[0048] Specifically, in Figure 4 In the first winding portion 72, the center of gravity is located on an imaginary line segment M that is perpendicular to the imaginary line segment N connecting the connection point E of the first winding portion 72 and the second winding portion 73 and the center point C of the pendulum axis 410, and the center of gravity is located at an imaginary point P. The length Q between the imaginary point P and the center point C of the pendulum axis 410 satisfies the following formula (1).

[0049]

[0050] In addition, in the above formula (1), R is the length of the imaginary line segment N from the center point C of the swing shaft 410 to the connection point E of the first winding portion 72 and the second winding portion 73. In addition, L is the length of the arc from the connection point S of the inner end 71 and the first winding portion 72 to the connection point E of the first winding portion 72 and the second winding portion 73, that is, the length of the first winding portion 72.

[0051] In this embodiment, the first winding portion 72 is configured such that its length L is slightly shorter than the length of the outer peripheral shape portion 443, which will be described later.

[0052] The second winding portion 73 is formed continuously from the first winding portion 72. In this embodiment, when viewed from above along the axial direction of the pendulum axis 410, the second winding portion 73 is formed along an Archimedean curve. In addition, in this embodiment, a bend 722 is formed in the middle of the outermost periphery of the second winding portion 73.

[0053] The outer end portion 74 is continuously formed from the second winding portion 73 and is fixed as an outer stud (not shown in the figure). That is, the inner end portion 71 of the hairspring 70 is fixed to the inner stud 440, and the outer end portion 74 is fixed to the outer stud (not shown in the figure).

[0054] [Inner pile]

[0055] Figure 5 This is a sectional view showing the inner pile 440. Figure 6 This is a three-dimensional diagram representing the inner pile 440.

[0056] like Figures 3-6 As shown, the inner pile 440 is fixed to the swing shaft 410. In this embodiment, the inner pile 440 includes an inner pile main body 441, a fixing part 442, an outer peripheral shape part 443, a swing shaft insertion hole 444, a center of gravity adjustment part 445, and a support part 446.

[0057] The inner pile body 441 is formed in a generally cylindrical shape. Furthermore, the outer peripheral surface of the inner pile body 441 is provided as an outer peripheral shape portion 443. In addition, when viewed from the axial direction of the swing shaft 410, a swing shaft insertion hole 444 is formed in the inner pile body 441 at a position eccentric from the center of the inner pile body 441.

[0058] Furthermore, in this embodiment, a thin-walled portion 4411 with a reduced wall thickness is formed in the inner pile body portion 441. Therefore, when the pendulum shaft 410 is inserted into the pendulum shaft insertion hole 444, if the torque when the inner pile 440 is fixed to the pendulum shaft 410 is too strong, this thin-walled portion 4411 will break, thereby adjusting the torque to an appropriate value. Therefore, by aligning the rotational phase with the pendulum pin (not shown), the torque when the inner pile 440 rotates relative to the pendulum shaft 410 can be stabilized. Additionally, when the aforementioned torque when the pendulum shaft 410 is inserted into the pendulum shaft insertion hole 444 is appropriate, the thin-walled portion 4411 is configured not to break.

[0059] The fixing part 442 is the part that fixes the inner end 71 of the hairspring 70. In this embodiment, the fixing part 442 includes a first abutting part 4421, a second abutting part 4422, and a third abutting part 4423.

[0060] The first abutting portion 4421 abuts against one surface of the inner end portion 71 at a position near the first winding portion 72. The second abutting portion 4422 abuts against another surface of the inner end portion 71 near approximately the center. Furthermore, the third abutting portion 4423 abuts against one surface of the inner end portion 71 at a position on the inner end side. That is, in this embodiment, the fixing portion 442 fixes the inner end portion 71 by having the first abutting portion 4421 and the third abutting portion 4423 abut against one surface of the inner end portion 71, and the second abutting portion 4422 abut against the other surface of the inner end portion 71, thereby clamping the inner end portion 71 in place using the first abutting portion 4421, the second abutting portion 4422, and the third abutting portion 4423.

[0061] As described above, the outer peripheral shape portion 443 is configured as the outer peripheral surface of the cylindrical inner stud body portion 441. That is, the outer peripheral shape portion 443 is arc-shaped when viewed from above from the axial direction of the pendulum axis 410. Furthermore, in this embodiment, the outer peripheral shape portion 443 is positioned opposite the inner surface of the first winding portion 72, and is configured to form the first winding portion 72 into the aforementioned Grossman-type shape. The method for using the outer peripheral shape portion 443 to form the first winding portion 72 into a Grossman-type shape will be described later.

[0062] The pendulum shaft insertion hole 444 is an insertion hole for inserting the pendulum shaft 410. In this embodiment, as described above, the pendulum shaft insertion hole 444 is formed in the inner pile body 441 at a position eccentric from the center of the inner pile body 441.

[0063] The center of gravity adjustment unit 445 is a component used to adjust the center of gravity of the inner pile 440.

[0064] Here, as mentioned earlier, since the pendulum shaft insertion hole 444 is formed at a position eccentric to the center point C of the inner pile body 441, the center of gravity of the inner pile body 441 is offset from the center point C of the pendulum shaft 410. Therefore, when the inner pile body 441 is rotated about the pendulum shaft 410 as the rotation axis, it rotates in a state where the center of gravity is offset from the center of rotation.

[0065] Therefore, in this embodiment, the center of gravity adjustment part 445 is integrally formed with the inner pile main body part 441. Specifically, the center of gravity adjustment part 445 is formed such that the center of gravity of the inner pile 440 coincides with the center point C of the pendulum axis 410. Thus, when the inner pile 440 rotates around the pendulum axis 410 as the center of rotation, it is possible to prevent the center of gravity of the inner pile 440 from being misaligned with the center point C of the pendulum axis 410.

[0066] In addition, in this embodiment, the center of gravity adjustment part 445 is formed at two locations when viewed from the axial direction of the swing shaft 410, sandwiching the thin-walled part 4411 of the inner pile main body part 441.

[0067] In this embodiment, when viewed from the side in a direction perpendicular to the axial direction of the balance shaft 410, the center-of-gravity adjustment part 445 is formed at a position offset from the fixing part 442 in the axial direction of the balance shaft 410, i.e., in the thickness direction of the inner stud body 441. Therefore, when the inner end portion 71 of the hairspring 70 is fixed to the fixing part 442, the hairspring 70 and the center-of-gravity adjustment part 445 are positioned offset in the thickness direction of the inner stud body 441. Thus, interference between the center-of-gravity adjustment part 445 and the hairspring 70 can be prevented.

[0068] The support portion 446 is integrally formed with the inner stud body portion 441, and serves as the support for the hairspring 70 when the first winding portion 72 is formed along the Grossman-type shape. Details regarding the support of the hairspring 70 by the support portion 446 will be described later.

[0069] [Manufacturing method of hairspring]

[0070] Next, the manufacturing method of the hairspring 70 will be explained.

[0071] Figures 7-11 This is a diagram illustrating the manufacturing method of the hairspring 70.

[0072] First, such as Figure 7 As shown, a spiral spring material 170, made of a plate-shaped elastic material of metal, is formed along the Archimedes curve. Then, the inner end of the spiral spring material 170 is fixed to the inner stake 440. At this time, it is also possible to pre-install the inner stake 440 with the inner stake 440. Figure 4 The connection point S is bent near the location shown, and then the inner end of the hairspring material 170 is fixed to the fixing part 442 of the inner pile 440.

[0073] Next, the inner stud 440, to which the hairspring material 170 is fixed, is installed on the rotary table B equipped with the terminal T. At this time, with the portion of the hairspring material 170 that is connected to the inner end of the fixing part 442, i.e., the portion of the hairspring material 170 that extends out of the fixing part 442, sandwiched between the outer peripheral shape part 443 and the terminal T, the protrusion BA of the rotary table B is inserted into the swing shaft insertion hole 444 of the inner stud 440.

[0074] Next, as Figure 8 As shown, with the hairspring material 170 sandwiched between the outer peripheral shape portion 443 and the terminal T, the rotary table B rotates counterclockwise around the protrusion BA of the rotary table B as the rotation center. At this time, as... Figure 9 As shown, the terminal T is operated by pressing the hairspring material 170 against the outer peripheral shape portion 443 under a specified load. Thus, as... Figure 8 As shown, the hairspring material 170 is wound along the outer peripheral shape portion 443. At this time, a portion of the hairspring material 170 is supported by the support portion 446 of the inner stud 440. Therefore, it is possible to prevent the hairspring material 170 from being wound around the outer peripheral shape portion 443 in a state of displacement in the thickness direction of the inner stud body portion 441.

[0075] Then, as Figure 10 As shown, while rotating the rotary table B at a specified rotational speed, the section of the hairspring material 170 from the inner end to a specified length is wound along the outer peripheral shape portion 443.

[0076] In addition, in this embodiment, when viewed from above, the length of the section of the hairspring material 170 wound along the outer peripheral shape portion 443, that is, the length of the first winding portion 72, is configured to be shorter than the length of the outer peripheral shape portion 443.

[0077] Then, if terminal T is separated from the hairspring material 170 and inner stud 440 is removed from the rotary table B, then as follows Figure 11 As shown, a hairspring 70 is manufactured having a first winding portion 72 formed along a Grossman shape and a second winding portion 73 formed along an Archimedes curve. That is, in this embodiment, during the manufacturing process of the hairspring 70, the outer peripheral shape portion 443 of the inner stud 440 is used to form the first winding portion 72 into a Grossman shape.

[0078] Furthermore, the specified load on the hairspring material 170 pressed at terminal T is confirmed through prior testing. That is, the specified load is set in such a way that the section of hairspring material 170 wound along the outer peripheral shape portion 443 up to the specified length is formed into a Grossman-type shape.

[0079] Then, the inner stud 440 with the hairspring 70 fixed and the balance wheel 420 fixed to the balance shaft 410 are manufactured to create the balance wheel and hairspring mechanism 400.

[0080] [Effects of the Implementation Method]

[0081] The following effects can be obtained from this embodiment.

[0082] In this embodiment, the inner stud 440 is positioned opposite the inner surface of the first winding portion 72 and has an outer peripheral shape portion 443 for forming the first winding portion 72 into a Grossman-type shape.

[0083] Therefore, by winding the portion of the hairspring 70 corresponding to the first winding portion 72 along the outer peripheral shape portion 443, the first winding portion 72 can be made into a Grossman-type shape. Therefore, even without using LIGA technology, a portion of the hairspring 70 can be formed into a Grossman-type shape, thus making it easy to manufacture a metal hairspring 70 with excellent isochronism.

[0084] In this embodiment, the inner pile 440 has a center of gravity adjustment part 445 for adjusting the center of gravity of the inner pile 440 to the center position of the swing axis 410.

[0085] Therefore, even if the pendulum shaft insertion hole 444 for inserting the pendulum shaft 410 is located off-center from the center of the inner pile 440, the center of gravity of the inner pile 440 can be aligned with the center of the pendulum shaft 410. Thus, adverse conditions caused by the misalignment of the center of the pendulum shaft 410 with the center of gravity of the inner pile 440 can be suppressed.

[0086] In this embodiment, the outer peripheral shape portion 443 is configured as the outer peripheral surface of the cylindrical inner pile main body portion 441. That is, the outer peripheral shape portion 443 is formed as an arc when viewed from above from the axial direction of the pendulum axis 410.

[0087] Therefore, the outer peripheral shape portion 443 used to make the first winding portion 72 into a Grossman-type shape can be formed with a simple structure. Therefore, the inner pile 440 can be easily manufactured. Furthermore, the shape of the outer peripheral shape portion 443 can be formed with high precision, so when the first winding portion 72 is formed using the outer peripheral shape portion 443, the shape deviation of the first winding portion 72 can be reduced.

[0088] In this embodiment, when viewed from above from the axial direction of the swing shaft 410, the length of the first winding portion 72 is configured to be shorter than the length of the outer peripheral shape portion 443.

[0089] Therefore, the portion corresponding to the first winding portion 72 can be reliably wound onto the outer peripheral shape portion 443, thereby reducing the shape deviation of the first winding portion 72.

[0090] In this embodiment, the manufacturing process of the balance wheel and hairspring mechanism 400 includes the following steps: forming the hairspring material 170 along the Archimedes curve; fixing the inner end of the hairspring material 170 to the inner stud 440; and using the outer peripheral shape portion 443 of the inner stud 440 to form the section of the hairspring material 170 from the inner end to a predetermined length into a Grossman shape.

[0091] Therefore, the specified intervals in the hairspring material 170 can be easily formed into a Grossman-type shape.

[0092] [Variation Example]

[0093] Furthermore, this disclosure is not limited to the aforementioned embodiments, and modifications and improvements within the scope of achieving the purpose of this disclosure are included in this disclosure.

[0094] In the described embodiment, the fixing portion 442 is configured to have a first abutting portion 4421, a second abutting portion 4422, and a third abutting portion 4423 that abut against the inner end portion 71 of the hairspring 70, but it is not limited to this. For example, the fixing portion may be configured as a groove that holds the inner end portion of the hairspring, or it may be configured to laser weld the inner end portion to the fixing portion, as long as it is configured to fix the inner end portion.

[0095] In the described embodiment, the center of gravity adjustment part 445 is integrally formed with the inner pile main body part 441, but it is not limited to this. For example, the center of gravity adjustment part may also be provided by a component different from the inner pile main body part.

[0096] In the embodiment described above, the outer peripheral shape portion 443 is configured as the outer peripheral surface of the cylindrical inner pile body portion 441, but it is not limited to this, as long as the first winding portion can be formed into a Grossman-type shape.

[0097] Furthermore, when the hairspring 70 contracts along with the rotational motion of the balance wheel and hairspring mechanism 400, if the differential rate effect caused by the change in contact state near the connection point S becomes a problem, a localized recessed shape can be provided in the outer peripheral shape portion 443 near the location opposite the connection point S. For example, when viewed from above in the axial direction of the balance shaft 410, the outer peripheral shape portion 443 can be provided with a straight line instead of an arc shape. Alternatively, it can be configured such that a component with a shape that forms only a Grossman-type shape near the connection point S is provided on the rotating platform B.

[0098] In the described embodiment, a thin-walled portion 4411 is formed in the inner pile body portion 441, but this is not a limitation. For example, the case in which the inner pile body portion does not form a thin-walled portion is also included in this disclosure. In this case, the pendulum shaft can be inserted into the pendulum shaft insertion hole of the inner pile in accordance with the rotation phase of the pendulum pin. Furthermore, the thin-walled portion can also be provided in the portion of the outer peripheral shape portion that does not wrap around the first winding portion. Furthermore, it is also possible to configure a gap extending from the pendulum shaft insertion hole along the outer peripheral direction in the portion of the outer peripheral shape portion that does not wrap around the first winding portion, instead of the thin-walled portion, so that when the inner pile and the pendulum shaft are engaged, the inner pile and the pendulum shaft are fixed with a stable holding torque by the reaction force of the elastic deformation of the gap opening.

[0099] [Summary of this disclosure]

[0100] The balance wheel and hairspring mechanism disclosed herein comprises: a balance shaft rotatably supported on a support member; an inner stud fixed to the balance shaft; and a metal hairspring fixed to the inner stud, the hairspring having: an inner end portion fixed to the inner stud; a first winding portion continuously formed from the inner end portion along a Grossman-type shape; and a second winding portion continuously formed from the first winding portion along an Archimedean curve, the inner stud having: a fixing portion fixing the inner end portion of the hairspring; and an outer peripheral shape portion disposed at a position opposite to the inner surface of the first winding portion for forming the first winding portion into a Grossman-type shape.

[0101] Therefore, by winding the portion of the hairspring corresponding to the first winding portion along the outer circumferential shape, the first winding portion can be formed into a Grossman-type shape. Thus, even without using LIGA technology, a portion of the hairspring can be formed into a Grossman-type shape, making it easy to manufacture metal hairsprings with excellent isochronism.

[0102] In the balance wheel and hairspring mechanism disclosed herein, the inner stud may also have a center of gravity adjustment part for adjusting the center of gravity of the inner stud to the center position of the balance shaft.

[0103] Therefore, even if the insertion hole for inserting the pendulum shaft is located off-center from the center of the inner pile, the center of gravity of the inner pile can still be aligned with the center of the pendulum shaft. This prevents adverse conditions caused by the center of the pendulum shaft being misaligned with the center of gravity of the inner pile.

[0104] In the balance wheel and hairspring mechanism disclosed herein, the outer peripheral shape may be formed as an arc when viewed from above from the axial direction of the balance shaft.

[0105] Therefore, the outer peripheral shape portion used to make the first winding portion into a Grossman-type shape can be formed with a simple structure. Thus, the inner pile can be easily manufactured. Furthermore, the shape of the outer peripheral shape portion can be formed with high precision, thereby reducing shape deviations of the first winding portion when using this outer peripheral shape portion to form the first winding portion.

[0106] In the balance wheel and hairspring mechanism disclosed herein, the length of the first winding portion may be shorter than the length of the outer peripheral shape portion when viewed from the axial direction of the balance shaft.

[0107] Therefore, in the hairspring, the first winding portion can be reliably wound onto the outer peripheral shape portion. Thus, when the first winding portion is formed using the outer peripheral shape portion, shape deviation of the first winding portion can be reduced.

[0108] The movement disclosed herein has the aforementioned balance wheel and hairspring mechanism.

[0109] The mechanical clock disclosed herein has the aforementioned movement.

[0110] The method for manufacturing the balance wheel and hairspring mechanism disclosed herein is a method for manufacturing a balance wheel and hairspring mechanism having the following parts: a balance shaft, which is rotatably supported on a support member; an inner stud, which is fixed to the balance shaft; and a metal hairspring, the inner end of which is fixed to the inner stud. In this method for manufacturing the balance wheel and hairspring mechanism, the following steps are included: forming the hairspring along an Archimedean curve; fixing the inner end of the hairspring to the inner stud; and using the outer peripheral shape of the inner stud to form the section of the hairspring from the inner end to a predetermined length into a Grossman-type shape.

[0111] Therefore, it is easy to form a specified range in the hairspring into a Grossman-type shape.

Claims

1. A balance wheel and hairspring mechanism, characterized in that, This balance wheel and hairspring mechanism has the following features: The pivot axis rotates freely and is supported by the supporting components; The inner stake, which is fixed to the swing shaft; and A metal hairspring, which is fixed to the inner stud. The hairspring has: an inner end portion fixed to the inner stud; a first winding portion continuously formed from the inner end portion along a Grossman-shaped pattern; and a second winding portion continuously formed from the first winding portion along an Archimedean curve. The inner stud has: a fixing portion for fixing the inner end of the hairspring; and an outer peripheral shape portion disposed at a position opposite to the inner surface of the first winding portion for forming the first winding portion into a Grossman-type shape.

2. The balance wheel and hairspring mechanism according to claim 1, characterized in that, The inner pile has a center of gravity adjustment part for adjusting the center of gravity of the inner pile to the center position of the pendulum axis.

3. The balance wheel and hairspring mechanism according to claim 1 or 2, characterized in that, When viewed from above from the axial direction of the pendulum axis, the outer peripheral shape is formed as an arc.

4. The balance wheel and hairspring mechanism according to claim 1 or 2, characterized in that, When viewed from above from the axial direction of the swing shaft, the length of the first winding portion is formed to be shorter than the length of the outer peripheral shape portion.

5. A movement, wherein, The movement has the balance wheel and hairspring mechanism as described in any one of claims 1 to 4.

6. A mechanical clock, wherein, The mechanical clock has the movement described in claim 5.

7. A method for manufacturing a balance wheel and hairspring mechanism, the balance wheel and hairspring mechanism comprising: a balance shaft rotatably supported on a support member; an inner stud fixed to the balance shaft; and a metal hairspring, the inner end of which is fixed to the inner stud, the method for manufacturing the balance wheel and hairspring mechanism being characterized by comprising the following steps: The hairspring is formed along the Archimedean curve; The inner end of the hairspring is fixed to the inner stud; and The outer peripheral shape of the inner stud is used to form the section of the hairspring from the inner end to a predetermined length into a Grossman shape.

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