Method for manufacturing timepiece gear, plate-shaped member, timepiece gear, and timepiece

Abstract

The invention provides a method for manufacturing a timepiece gear, a plate-shaped member, a timepiece gear, and a timepiece, which can connect a connection part to the gear even when the tooth spacing of the gear is small. A method for manufacturing a gear (50) includes: an outer shape forming step of forming a gear (50) having a plurality of teeth (51), a frame portion (55) disposed on an outer side of the gear (50), and a connection portion (56) having higher flexibility than the teeth (51) and connecting the frame portion (55) and a tip portion of the teeth (51) by etching a silicon wafer (70) made of a brittle material; and a cutting step for cutting the connection part (56) and the gear (50).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a timepiece gear, a plate-shaped component, a timepiece gear and a timepiece. Background Art

[0002] Patent Document 1 describes a method for manufacturing a gear for a watch using a silicon wafer, which is a brittle material. In this method, a gear, a frame portion arranged outside the gear, and a connecting rod connecting the gear and the frame portion are formed by etching a silicon wafer. Then, the gear and the connecting rod are cut off to remove the gear. Before being cut off, the connecting rod is connected to the outer peripheral surface between the teeth of the gear.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-46348

[0004] However, in Patent Document 1, since the connecting rod is connected between teeth, there is a problem that it is difficult to apply to gears with a small tooth spacing, such as gears that mesh with other gears. Specifically, it is difficult to provide the connecting rod itself in a gear with a small tooth spacing, and if the part where the connecting rod is cut protrudes, it may not mesh with other gears normally. Summary of the invention

[0005] The manufacturing method of a watch gear includes the following steps: forming the following parts by etching a plate-like part of a brittle material: a watch gear having a plurality of teeth; a frame portion arranged on the outside of the watch gear; and a connecting portion having higher flexibility than the teeth and connecting the frame portion to the top end of the teeth; and cutting the connecting portion from the watch gear.

[0006] The plate-like component is a plate-like component made of a brittle material, and comprises: a watch gear having a plurality of teeth; a frame portion arranged outside the watch gear; and a connecting portion having higher flexibility than the teeth and connecting the frame portion to the top end of the teeth.

[0007] The timepiece gear is produced by cutting a plate-like member made of a brittle material, and has a plurality of teeth including teeth having a cut surface formed when the tooth is cut from the plate-like member at a tip end.

[0008] A timepiece includes the above-mentioned timepiece gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a top view of the movement of the mechanical timepiece as seen from the front side.

[0010] Figure 2 It is a top view showing the structure of the third wheel & pinion.

[0011] Figure 3 is a top view showing the silicon wafer after etching.

[0012] Figure 4 This is an enlarged top view of a gear included in a silicon wafer.

[0013] Figure 5 It is an enlarged plan view showing the connection portion.

[0014] Figure 6 is a flowchart showing a method for manufacturing a gear.

[0015] Figure 7 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0016] Figure 8 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0017] Fig. 9 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0018] Fig.10 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0019] Fig.11 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0020] Fig.12 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0021] Fig.13 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0022] Fig.14 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0023] Fig.15 It is a process cross-sectional view for explaining the manufacturing method of a gear.

[0024] Fig.16 It is an explanatory diagram showing a schematic structure of an anisotropic etching apparatus.

[0025] Fig.17 This is a flowchart showing a method for manufacturing a mechanical timepiece.

[0026] Fig.18 It is an enlarged plan view showing a connection portion of a modified example.

[0027] Fig.19 It is an enlarged plan view showing a connection portion of a modified example.

[0028] Fig. 20It is an enlarged plan view showing a connection portion of a modified example.

[0029] Fig.21 This is an enlarged top view of a gear included in a silicon wafer of a modified example.

[0030] Description of symbols

[0031] 1: mechanical watch; 10: movement; 11: bottom plate; 11a: stem guide hole; 12: stem; 13: gear pull; 14: clutch lever; 15: clutch lever spring; 16: gear pull pressure plate; 17: vertical wheel; 20: small steel wheel; 21: large steel wheel; 22: barrel wheel; 25: second wheel; 26: third wheel; 27: fourth wheel; 30: escapement mechanism; 31: speed regulating mechanism; 35: escapement wheel; 36: escapement fork; 40: balance spring mechanism; 50: gear; 50a: opening; 51: tooth; 52: wheel rim; 53: holding portion; 54: connecting portion; 55: frame portion; 56: connecting portion; 56a: first end portion; 56b: second end portion; 57: hole portion; 58: cut surface; 60: shaft portion; 70: silicon wafer; 70a: first surface; 70b: second surface; 70c: hole; 71: silicon oxide film; 72: anti-etching agent film; 72a: opening portion; 81: anisotropic etching device; 82: workbench; 83: coil; 84: plasma; 85: protective film; A, B, C: width; D: direction; P: pitch circle; S: tooth thickness. DETAILED DESCRIPTION

[0032] Hereinafter, a timepiece and a timepiece gear according to the present embodiment and a method for manufacturing the same will be described with reference to the drawings.

[0033] In the following drawings, each layer and each component may be shown at a scale different from the actual scale in order to make each layer and each component a recognizable size.

[0034] Figure 1 This is a plan view of the movement 10 of the mechanical timepiece 1 as viewed from the front side.

[0035] In this embodiment, the side where the hands indicating the time are arranged is the back side, and the side where the spring driving the hands is arranged is the front side. Figure 1 In the figure, the front side of the paper is the front side, and the back side of the paper is the back side.

[0036] Mechanical clock 1 Figure 1 The movement 10 shown is constituted by a case (not shown) which houses the movement 10. The mechanical timepiece 1 is an example of a timepiece.

[0037] The movement 10 has a bottom plate 11. The bottom plate 11 is a plate member for supporting or positioning various components. A dial (not shown) is arranged on the back side of the bottom plate 11. A gear train consisting of a plurality of gears is arranged on the front side and the back side of the bottom plate 11. The gear train arranged on the front side of the bottom plate 11 is also called the front gear train, and the gear train arranged on the back side of the bottom plate 11 is also called the back gear train.

[0038] A stem guide hole 11a is formed on the base plate 11, which is parallel to the base plate 11 and guides the shaft-shaped stem 12 in the direction from the outer edge toward the center. And the stem 12 is assembled in the stem guide hole 11a in a manner that it can move in the axial direction and rotate around the axis. A pull gear 13, a clutch rod 14, a clutch rod spring 15, and a pull gear pressure plate 16 are arranged near the stem 12. The pull gear 13, the clutch rod 14, the clutch rod spring 15, and the pull gear pressure plate 16 constitute a switching mechanism for switching the transmission destination of the rotational force of the stem 12.

[0039] The stem 12 is inserted through a vertical wheel 17 that can rotate coaxially with the stem 12. In addition, a clutch wheel (not shown) that rotates together with the stem 12 is arranged on the stem 12. The clutch wheel rotates coaxially with the stem 12 and can be moved along the axial direction of the stem 12 by a switching mechanism. When the stem 12 changes its position in the axial direction, the switching mechanism switches the clutch wheel to a state of meshing and a state of not meshing with the vertical wheel 17. In addition, a small steel wheel 20 that meshes with the vertical wheel 17, a large steel wheel 21 that meshes with the small steel wheel 20, and a barrel wheel 22 that stores the mainspring are rotatably provided on the bottom plate 11.

[0040] When the stem 12 moves in the axial direction and is arranged at the first stem position closest to the center of the movement 10, the clutch wheel meshes with the vertical wheel 17. When the operator rotates the stem 12 in this state, the vertical wheel 17 rotates together with the clutch wheel. And, by the rotation of the vertical wheel 17, the small steel wheel 20 rotates. And, by the rotation of the small steel wheel 20, the large steel wheel 21 rotates. Furthermore, by the rotation of the large steel wheel 21, the mainspring stored in the barrel wheel 22 is wound. The mainspring is the power source that drives the movement 10. In addition, when the stem 12 is arranged at a position closer to the outside than the first stem position, the meshing of the clutch wheel and the vertical wheel 17 is released, and the clutch wheel meshes with the hand setting wheel (not shown) used for time synchronization, etc.

[0041] The second wheel 25, the third wheel 26 and the fourth wheel 27 are rotatably arranged on the bottom plate 11. The second wheel 25, the third wheel 26 and the fourth wheel 27 respectively have a gear and a cannon wheel that rotate integrally. The above-mentioned front train wheel is composed of the barrel wheel 22, the second wheel 25, the third wheel 26 and the fourth wheel 27. The front train wheel has the function of transmitting the rotational force of the barrel wheel 22. In addition, on the front side of the movement 10, an escapement mechanism 30 and a speed regulating mechanism 31 are arranged on the bottom plate 11. The escapement mechanism 30 and the speed regulating mechanism 31 adjust the rotation speed of the front train wheel.

[0042] The barrel wheel 22 meshes with the gear of the second wheel 25. A minute hand (not shown) is connected to the second wheel 25. The gear of the second wheel 25 meshes with the gear of the third wheel 26. The gear of the fourth wheel 27 meshes with the gear of the third wheel 26. A second hand (not shown) is connected to the fourth wheel 27. The escapement mechanism 30 is a mechanism for controlling the rotation of the front train. The escapement mechanism 30 includes an escape wheel 35 and a pallet fork 36. The escape wheel 35 includes a gear meshed with the gear of the fourth wheel 27, and rotates by receiving the torque of the fourth wheel 27. The pallet fork 36 rotates the escape wheel 35 regularly as the speed regulating mechanism 31 operates. The speed regulating mechanism 31 includes a balance spring mechanism 40 that swings at a fixed period, and adjusts the rotation speed of the front train meshed with the escape wheel 35 by adjusting the rotation speed of the escape wheel 35.

[0043] Next, the third wheel & pinion 26 among the various components described above will be described in detail.

[0044] Figure 2 1 is a plan view showing the structure of the third wheel & pinion 26 .

[0045] like Figure 2 As shown, the third wheel & pinion 26 includes a gear 50 and a shaft portion 60 that serves as a rotation axis of the gear 50. The gear 50 is composed of an annular rim portion 52 having a plurality of teeth 51 on the outer circumferential surface, a retaining portion 53 through which the shaft portion 60 is inserted, and a plurality of connecting portions 54 that radially extend from the retaining portion 53 and connect the rim portion 52 and the retaining portion 53. An opening portion 50a surrounded by the rim portion 52, the retaining portion 53, and two adjacent connecting portions 54 is formed in the gear 50. Specifically, the gear 50 is provided with the same number of opening portions 50a as the connecting portions 54 along the circumferential direction. The gear 50 is connected to the pinion 28 (see FIG. 2 ) of the fourth wheel & pinion 27. Figure 1 ) are meshed. The gear 50 is an example of a gear for a timepiece.

[0046] The shaft portion 60 is integrally formed with a pinion 61 that meshes with the gear of the center wheel & pinion 25. The shaft portion 60 is inserted through a hole portion 57 (see FIG. 1 ) formed in the center of the gear 50. Figure 4 ) and is fixed to the gear 50. Therefore, the gear 50 and the pinion 61 rotate integrally.

[0047] The gear 50 is plate-shaped and has a substantially uniform thickness over the entire surface. The gear 50 is made of a brittle material having a crystal orientation, such as single crystal silicon. The material of the gear 50 of the present embodiment is single crystal silicon. Specifically, the gear 50 is formed by etching a silicon wafer made of single crystal silicon. The manufacturing method of the gear 50 is described below.

[0048] Figure 3 is a top view showing the silicon wafer 70 after etching, Figure 4 FIG. 5 is an enlarged top view of a gear 50. Figure 3 as well as Figure 4 , mutually perpendicular X-axis, Y-axis and Z-axis are shown. The X-axis is a coordinate axis parallel to the surface of the silicon wafer 70. The Y-axis is a coordinate axis parallel to the surface of the silicon wafer 70 and perpendicular to the X-axis. The Z-axis is a coordinate axis perpendicular to the surface of the silicon wafer 70, that is, the XY plane. Hereinafter, the direction parallel to the XY plane is also referred to as the plane direction, and the direction intersecting the XY plane is also referred to as the intersecting direction.

[0049] like Figure 3 As shown, the silicon wafer 70 is a disk-shaped mother substrate on which a plurality of gears 50 can be formed. The silicon wafer 70 is an example of a plate-shaped component. On one silicon wafer 70, a plurality of gears 50 are arranged in a matrix along the X-axis and the Y-axis. Each gear 50 is surrounded by a frame 55 that is continuous with the peripheral edge of the silicon wafer 70. That is, the frame 55 is arranged on the outside of the gear 50.

[0050] In this embodiment, the dimension of the silicon wafer 70 along the Z axis, that is, the thickness of the silicon wafer 70, is about 100 μm to 200 μm. The thickness of the silicon wafer 70 corresponds to the tooth width of the gear 50. In addition, the diameter of the tooth tip circle (not shown), that is, the diameter of the circle passing through the top of the tooth 51, is about 5 mm to 6 mm, and the tooth thickness S (see Figure 5 ), that is, the dimension of the tooth 51 along the pitch circle P is about 100 μm to 200 μm. However, the tooth width, the diameter of the tooth tip circle, and the tooth thickness S are not limited to the above ranges and may be outside the above ranges.

[0051] The gear 50 is connected to the frame 55 via the connection portion 56. That is, the connection portion 56 connects the gear 50 to the frame 55, and the gear 50 is supported by the frame 55 via the connection portion 56. The connection portion 56 is connected to the top ends of two teeth 51 among the plurality of teeth 51 included in the gear 50. In the present embodiment, the angle formed by the extending directions of the two teeth 51 connected by the connection portion 56 is approximately 180°.

[0052] Figure 5 It is an enlarged plan view showing the connection portion 56 .

[0053] like Figure 5As shown, the connecting portion 56 as a whole extends from the tip of the tooth 51 in a direction substantially the same as the extending direction of the tooth 51, and reaches the frame portion 55. That is, when the end connected to the tip of the tooth 51 of the two ends of the connecting portion 56 is set as the first end 56a, and the end connected to the frame portion 55 is set as the second end 56b, the direction D from the first end 56a toward the second end 56b is substantially the same as the extending direction of the tooth 51.

[0054] The shape of the connecting portion 56 when viewed along the Z axis is a meandering shape, that is, a wavy line shape. Figure 5 In the plan view shown in the figure, the connection portion 56 is oriented in the direction D while repeatedly bending counterclockwise and clockwise alternately. Therefore, the shape of the connection portion 56 can also be said to be a shape that is alternately bent in opposite directions.

[0055] The width A of the connecting portion 56, which is equivalent to the line width of the wavy line, is approximately uniform throughout the entire range except for the first end 56a and the second end 56b. In the present embodiment, the width A of the connecting portion 56 is approximately 30 μm, which is sufficiently smaller than the tooth thickness S of the tooth 51. A constriction is formed at the first end 56a. Therefore, the first end 56a is smaller in width than other parts of the connecting portion 56. Specifically, the first end 56a is smaller in width as it moves toward the end. That is, the width B at the end of the first end 56a is smaller than the width A of the connecting portion 56. On the other hand, the width C of the second end 56b is greater than the width A of the connecting portion 56.

[0056] The connecting portion 56 is flexible and can bend in a planar direction parallel to the XY plane. Strictly speaking, the teeth 51 of the gear 50 can also be flexible, but the width A of the connecting portion 56 is sufficiently small compared to the tooth thickness S of the teeth 51, so the connecting portion 56 has a sufficiently higher flexibility than the teeth 51. From the viewpoint of improving flexibility, the width A of the connecting portion 56 is preferably as small as possible. On the other hand, if the width A of the connecting portion 56 is too small, it is difficult to form the connecting portion 56 by etching. Therefore, the width A of the connecting portion 56 is preferably 10 μm to 50 μm, and more preferably 20 μm to 40 μm.

[0057] The gear 50 connected to the frame 55 via the connection portion 56 is cut at the first end 56a of the connection portion 56, and is separated from the silicon wafer 70. Therefore, on the separated gear 50, a cut surface 58 is formed at the tip of the two teeth 51 connected to the connection portion 56 (see Figure 2 ). That is, the cut surface 58 is a surface connected to the first end portion 56a of the connecting portion 56. The cut surface 58 can protrude outward from the tip of the tooth 51, but as long as it protrudes to a degree that does not contact the pinion 28 of the second wheel 27 that is the meshing object, it will not affect the operation.

[0058] In addition, the single crystal silicon used as the raw material of the gear 50 has multiple crystal planes and has the property of being easily split on the crystal planes. That is, the single crystal silicon can be cut with less force when it is cut along the crystal planes than when it is cut on the faces other than the crystal planes. In addition, when it is cut along the crystal planes, it is possible to suppress the cracks generated by the cutting from extending in directions other than the crystal planes. Therefore, it is preferred that the front and back surfaces of the gear 50 parallel to the XY plane and the two cut surfaces 58 connected to the connecting portion 56 become crystal planes.

[0059] Next, a method for manufacturing the gear 50 included in the third wheel & pinion 26 will be described.

[0060] Figure 6 is a flowchart showing a method for manufacturing the gear 50. Figure 7 to Figure 15 It is a process cross-sectional view for explaining the manufacturing method of the gear 50.

[0061] like Figure 6 As shown, the method for manufacturing the gear 50 includes steps S1 to S6. That is, the gear 50 is manufactured by sequentially performing steps S1 to S6.

[0062] Step S1 is an oxide film forming process. Figure 7 As shown, this step is a step of forming a silicon oxide film 71 on one plane of a silicon wafer 70. The silicon wafer 70 is ground to an appropriate thickness and the surface is polished in advance so that the tooth width of the gear 50 becomes a desired dimension.

[0063] The silicon wafer 70 has two planes, a first surface 70a and a second surface 70b, on the front and back surfaces. In step S1, a silicon oxide film 71 is formed on the second surface 70b. The silicon oxide film 71 is formed by a CVD (Chemical Vapor Deposition) method. The film thickness of the silicon oxide film 71 is not particularly limited, and is, for example, about 1 μm. The silicon oxide film 71 is formed to prevent the hole 70c formed in the etching process of step S4 described later from penetrating the front and back surfaces.

[0064] Step S2 is a photoresist coating process. Figure 8 As shown in FIG. 1 , this process is a process of forming a resist film 72 on the first surface 70a of the silicon wafer 70. First, a resin solution in which a photosensitive resin is dissolved is applied to the first surface 70a of the silicon wafer 70 by spin coating or spray coating. Next, the resin solution is dried to remove the solvent, thereby forming the resist film 72. The photosensitive resin can be any of a negative type and a positive type.

[0065] Step S3 is an exposure and development process. This process is a process for forming an etching mask for forming the gear 50. First, use Figure 3The photomask having a pattern corresponding to the plurality of gears 50, the frame portion 55, and the plurality of connecting portions 56 connecting them is used to expose the resist film 72. Thereafter, when the resist film 72 is developed to remove unnecessary parts, as shown in FIG. Fig. 9 As shown, an opening 72a corresponding to the pattern of the photomask is formed in the resist film 72. The opening 72a corresponds to a portion where silicon is removed from the silicon wafer 70 by etching. That is, the resist film 72 having the opening 72a functions as an etching mask.

[0066] Step S4 is an etching process. This process is a process of etching the silicon wafer 70 using the resist film 72 as an etching mask to form the shapes of the gear 50, the frame 55, and the connecting portion 56. As etching, for example, anisotropic etching such as deep reactive ion etching (DRIE) based on inductively coupled plasma (ICP) is used.

[0067] Fig.16 1 is an explanatory diagram showing a schematic structure of an anisotropic etching apparatus 81 that performs DRIE using ICP.

[0068] like Fig.16 As shown, the anisotropic etching device 81 has a workbench 82 and a coil 83. On the workbench 82, the silicon wafer 70 is placed in a manner that the first surface 70a formed with the resist film 72 faces the coil 83 side. The anisotropic etching device 81 supplies SF6 gas while passing a high-frequency large current through the coil 83, thereby generating plasma 84. Then, when a bias is applied to the workbench 82, particles of the plasma 84 are introduced into the first surface 70a of the silicon wafer 70 from the opening 72a of the resist film 72. As a result, the silicon wafer 70 is etched from the first surface 70a side in the shape of the opening 72a and approximately perpendicular to the cross direction. The etched silicon becomes SiF4 and is removed. In order to prevent excessive heating of the silicon wafer 70, the anisotropic etching device 81 cools the silicon wafer 70 from the second surface 70b side using, for example, helium gas.

[0069] like Fig.10 As shown in FIG. 1 , when the silicon wafer 70 is cut to a specified depth, as shown in FIG. Fig.11 As shown, the anisotropic etching device 81 supplies C4F8 gas to the surface of the silicon wafer 70 to form a protective film 85 on the surface where silicon is exposed. Forming the protective film 85 is also called coating.

[0070] Afterwards, if Fig.12 As shown, the anisotropic etching device 81 etches the silicon wafer 70 again to expose the silicon, and then, as shown in FIG. Fig.13As shown, the protective film 85 is applied again. In this way, the anisotropic etching device 81 repeatedly performs etching of the silicon wafer 70 and coating of the protective film 85. This method is called the Bosch process. By this Bosch process, on the silicon wafer 70, as shown in FIG. Fig.14 As shown, a hole 70c reaching the silicon oxide film 71 is formed in a portion not covered by the resist film 72. Here, the hole 70c includes a gap between the gear 50 and the frame 55, the opening 50a formed in the gear 50, and the hole 57.

[0071] Step S5 is the oxide film removal process. Fig.15 As shown in FIG. 1 , this process is a process for removing the silicon oxide film 71 and the resist film 72 disposed on the silicon wafer 70. The resist film 72 can be removed by wet etching using fuming nitric acid, an organic solvent, or the like that can dissolve and peel off the resist film 72, or by oxygen plasma ashing. In this embodiment, after ashing by oxygen plasma ashing, an organic stripping liquid is further used to remove the residue.

[0072] The silicon oxide film 71 is removed by wet etching in which the silicon wafer 70 is immersed in a BHF (Buffered Hydrogen Fluoride) solution. Alternatively, the silicon oxide film 71 may be removed by reactive ion etching using parallel plates.

[0073] Above, through steps S1 to S5, a Figure 3 The plurality of gears 50, the frame 55, and the plurality of connecting parts 56 connecting them are shown. That is, a series of steps including steps S1 to S5 is a process of forming the outer shape of the gears 50, the frame 55, and the connecting parts 56 by etching the silicon wafer 70.

[0074] Step S6 is a cutting process. This process is a process of cutting the connecting portion 56 from the gear 50. The operation of cutting the connecting portion 56 from the gear 50 is performed using a tool with a thin tip such as tweezers. Specifically, the operator cuts the connecting portion 56 from the gear 50. Figure 3 and Figure 4 The silicon wafer 70 shown is placed on a workbench not shown in the figure, and the frame 55 is fixed on the workbench. Then, a tool is inserted into the opening 50a in the gear 50, and the gear 50 is displaced in the planar direction while the tool is in contact with the opening 50a. That is, the gear 50 is displaced in the planar direction relative to the frame 55 by the tool. At this time, the first end 56a of the connecting portion 56 also displaces following the displacement of the gear 50, but the connecting portion 56 bends due to its flexibility, so it will not break in the middle of the connecting portion 56. Moreover, when the force acting on the first end 56a reaches a specified value, the first end 56a breaks, and the connecting portion 56 and the gear 50 are cut off.

[0075] The gear 50 is separated from the silicon wafer 70 through step S6, and thus the gear 50 is completed. That is, the gear 50 is generated by cutting from the silicon wafer 70. In addition, at the top ends of the two teeth 51 connected by the connection portion 56, the cut surface 58 is formed when the gear 50 is cut from the silicon wafer 70. Therefore, the plurality of teeth 51 included in the gear 50 include two teeth 51 having the cut surface 58 at the top ends.

[0076] In addition, the two connecting parts 56 may be cut one by one, or the two connecting parts 56 may be cut in one operation. For example, if a shaft is inserted through the hole 57 in the center of the gear 50 and the gear 50 is rotated around the shaft, it is easy to cut the two connecting parts 56 in one operation. In addition, the direction in which the gear 50 is displaced is not limited to the planar direction, and the connecting part 56 may be cut by displacing the gear 50 in the intersecting direction.

[0077] Next, a method for manufacturing the mechanical timepiece 1 will be described.

[0078] Fig.17 1 is a flowchart showing a method for manufacturing the mechanical timepiece 1 .

[0079] like Fig.17 As shown, the method for manufacturing the mechanical timepiece 1 includes steps S11 to S13. That is, the mechanical timepiece 1 is manufactured by sequentially performing the steps S11 to S13.

[0080] Step S11 is a component assembly process, and is a process for assembling various components constituting the mechanical timepiece 1. For example, the third wheel & pinion 26, which is one of the components, is assembled by inserting the shaft 60 through the hole 57 of the gear 50 formed in the above steps S1 to S6. Components other than the third wheel & pinion 26 are also assembled as needed.

[0081] Step S12 is a movement assembly step, which is a step of assembling the movement 10 . This step includes a step of assembling various components such as the third wheel & pinion 26 to the bottom plate 11 .

[0082] Step S13 is a timepiece assembly step, which is a step of assembling the mechanical timepiece 1. This step includes a step of housing the movement 10 in a case (not shown). The mechanical timepiece 1 is completed through the above steps.

[0083] As described above, according to the gear 50 and the manufacturing method thereof of the present embodiment, the following effects can be obtained.

[0084] According to the present embodiment, the connection portion 56 is connected to the tip of the tooth 51, so even when the interval between the teeth 51 is small, the connection portion 56 can be connected to the gear 50. In addition, the connection portion 56 is connected to the tip of the tooth 51, so that the cut surface 58 after the connection portion 56 is cut can be suppressed from affecting the meshing with other gears.

[0085] Furthermore, when the flexible connection portion 56 is connected between the teeth 51, the bent connection portion 56 may come into contact with the teeth 51 during the cutting process of step S6. In this case, the connection portion 56 may break in the middle or damage the teeth 51. In contrast, in the present embodiment, the connection portion 56 is connected to the tip of the tooth 51, so that the connection portion 56 can be prevented from bending in the middle or damaging the teeth 51 during the cutting process.

[0086] In addition, when the connection portion 56 is connected between the teeth 51, the etched pattern becomes denser around the connection portion 56. As a result, the shape of the teeth 51 around the connection portion 56 and the shape of the teeth 51 outside the connection portion may differ due to the micro-loading effect. In contrast, in the present embodiment, the connection portion 56 is connected to the tip of the tooth 51, so that the etched pattern can be prevented from becoming locally dense, and the shape of the teeth 51 can be prevented from differing.

[0087] Furthermore, according to the present embodiment, since the shape of the connection portion 56 is a wavy line, the connection portion 56 can be bent more greatly than in the case of a straight line shape.

[0088] According to the present embodiment, a constriction is formed at the first end 56a of the connection portion 56. That is, the first end 56a is thinner than other parts of the connection portion 56, so when the connection portion 56 and the gear 50 are cut, the first end 56a is easily cut.

[0089] According to this embodiment, in the cutting process of step S6, when the gear 50 is displaced, the tool is not in contact with the teeth 51 but in contact with the opening 50a. In this way, when cutting, the tool is in contact with a portion other than the teeth 51, so that the tool can be prevented from damaging the teeth 51.

[0090] Furthermore, according to the silicon wafer 70 in a state where the outer shapes of the gear 50 , the frame portion 55 , and the connection portion 56 are formed through the outer shape forming step of the present embodiment, the gear 50 that exhibits the above-described effects can be easily formed.

[0091] Furthermore, according to the mechanical timepiece 1 of the present embodiment, since the gear 50 having the above-mentioned effects is used, stable operation can be achieved.

[0092] The above-mentioned embodiment may be modified as follows.

[0093] In the above-mentioned embodiment, the shape of the connecting portion 56 is set to a wavy line, but the number of waves in the wavy line and the amplitude of the waves are not limited to Figure 5 For example, it can be as follows Fig.18 A shape with fewer waves, such as the one shown, can also be Fig.19 As shown in the figure, the wave has a larger amplitude. Fig.19 The shape shown in FIG. 5 can also be said to be a shape in which a straight line portion is alternately bent in opposite directions, or a shape in which a straight line portion along a direction parallel to the XY plane and intersecting the direction D is alternately bent in opposite directions while heading in the direction D. In addition, the shape of the connecting portion 56 is not limited to a wavy line shape. Fig. 20 As shown, it may be a curved line other than a wavy line. As such, the shape of the connecting portion 56 is not particularly limited as long as it can follow the displacement of the gear 50 in the planar direction to a certain extent by flexibility.

[0094] In the above-mentioned embodiment, two connecting parts 56 are connected to each gear 50, and the angle formed by the extending directions of the two teeth 51 connected by the connecting part 56 is approximately 180°, but it is not limited to this. Fig.21 As shown, the angle formed by the extending directions of the two teeth 51 connected by the connecting portion 56 can be approximately 90°, or can be an angle other than this. In addition, the number of connecting portions 56 is not limited to two, and can be one, or can be three or more. In addition, in a structure in which multiple connecting portions 56 are connected to one gear 50, the shapes and sizes of the multiple connecting portions 56 can be the same or different.

[0095] In the above embodiment, the direction D from the first end 56a toward the second end 56b of the connection portion 56 is set to be substantially equal to the extending direction of the teeth 51 connected to the connection portion 56, but the direction D may be a direction different from the extending direction of the teeth 51.

[0096] In the above-mentioned embodiment, in the etching process of step S4, when the hole 70c is formed by the Bosch process, a concave-convex shape called a fan-shaped groove is formed on the surface after etching. A process of removing the fan-shaped groove may also be additionally performed. This process may be, for example, a process of etching the oxide film by immersing the silicon wafer 70 in a BHF solution after forming an oxide film with a depth of more than 1 μm on the silicon wafer 70 by thermal oxidation.

[0097] In the above-mentioned embodiment, in the component assembly process of step S11, after the shaft portion 60 is inserted through the gear 50, an oxidation treatment may be performed to form a silicon oxide film composed of silicon dioxide (SiO2) on the surface of the gear 50. When the gear 50 is subjected to the oxidation treatment, the mechanical strength of the gear 50 is improved by the silicon oxide film formed on the surface of the gear 50 composed of a material containing silicon. When the oxidation treatment is performed, it is preferable to perform a thermal oxidation treatment at a high temperature of 1000°C or more, for example.

[0098] In the above-described embodiment, silicon, which is a plate-like member of a brittle material, is used as the material of the gear 50, but the material of the gear 50 is not limited to silicon and may be, for example, silicon carbide, quartz, glass, sapphire, or the like.

[0099] In the above embodiment, the gear 50 of the third wheel 26 constituting the front wheel train of the mechanical timepiece 1 is illustrated, but the structure and manufacturing method of the gear 50 shown in the above embodiment can be applied to various gears such as other gears constituting the front wheel train and the gear constituting the back wheel train. In addition, the timepiece is not limited to the mechanical timepiece 1, and can also be other timepieces such as electronic timepieces. In other words, the structure and manufacturing method of the gear 50 shown in the above embodiment can also be applied to gears included in electronic timepieces and the like.

Claims

1. A method for manufacturing a gear for a watch, characterized in that: The manufacturing method of the watch gear comprises the following steps: The following parts are formed by etching a plate-like member of a brittle material: a timepiece gear having a plurality of teeth; a frame portion arranged outside the timepiece gear; and a connecting portion having a higher flexibility than the teeth and connecting the frame portion to the tip of the teeth; and The connecting portion and the timepiece gear are disconnected.

2. The method for manufacturing a timepiece gear according to claim 1, characterized in that: The width of the connecting portion is smaller than the tooth thickness of the tooth, and the shape of the connecting portion is a curve.

3. The method for manufacturing a timepiece gear according to claim 1, wherein: The width of the connecting portion is smaller than the tooth thickness of the tooth, and the shape of the connecting portion is a wavy line.

4. The method for manufacturing a timepiece gear according to claim 1, wherein: The width of the connecting portion is smaller than the tooth thickness of the tooth, and the connecting portion has a shape in which straight line portions are alternately bent in opposite directions.

5. The method for manufacturing a timepiece gear according to claim 1, characterized in that: A constriction is formed at an end portion of the connecting portion connected to the tip end portion of the tooth.

6. The method for manufacturing a timepiece gear according to claim 1, wherein: In the step of cutting the connecting portion and the timepiece gear, the timepiece gear is cut by displacing the connecting portion with respect to the frame portion using a tool. The tool is in contact with a portion of the timepiece gear other than the teeth.

7. A plate-shaped component, characterized in that: The plate-like member is made of a brittle material, The plate-like component has: A gear for a watch, having a plurality of teeth; a frame portion disposed outside the timepiece gear; and The connecting portion has higher flexibility than the teeth and connects the frame portion and the tip end of the teeth.

8. A gear for a watch, characterized in that: The timepiece gear is generated by cutting a plate-shaped member made of a brittle material, and has a plurality of teeth. The plurality of teeth include teeth having, at a tip portion, a cut surface formed when the teeth are cut from the plate-like member.

9. A timepiece, characterized in that: This timepiece has the timepiece gear according to claim 8.

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