Method for manufacturing watch gear, plate-like member, watch gear and watch

Abstract

To provide a method for manufacturing a watch gear capable of connecting a connection part to a gear even when an interval between the teeth of the gear is small, a plate-like member, a watch gear and a watch.SOLUTION: A method for manufacturing a gear 50 comprises: an outer shape forming process in which by etching a silicon wafer 70 made of a brittle material, a gear 50 having a plurality of teeth 51, a frame part 55 arranged on the outside of the gear 50, and a connection part 56 having higher flexibility than the teeth 51 and connecting the frame part 55 and the tip part of the teeth 51 are formed; and a cutting process of cutting off the connection part 56 from the gear 50.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a timepiece wheel, a plate-shaped member, a timepiece wheel, and a timepiece. [Background technology]

[0002] Patent Document 1 describes a manufacturing method for manufacturing a timepiece wheel using a silicon wafer, which is a brittle material. In this manufacturing method, a silicon wafer is etched to form a gear, a frame portion disposed on the outside of the gear, and tie bars connecting the gear and the frame portion. The gear and the tie bars are then cut to remove the gear. Before being cut, the tie bars are connected to the outer circumferential surface between the teeth of the gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-46348 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, because the tie bars are connected between the teeth, there is a problem that it is difficult to apply to gears with not so large tooth spacing, such as gears that mesh with other gears. Specifically, it is difficult to provide tie bars on gears with small tooth spacing, and if the cut-off portion of the tie bar protrudes, there is a risk that the gears will not be able to mesh properly with other gears. [Means for solving the problem]

[0005] A method for manufacturing a watch gear includes the steps of: etching a plate-shaped member made of a brittle material to form a watch gear having a plurality of teeth, a frame portion that is positioned on the outside of the watch gear, and a connecting portion that is more flexible than the teeth and connects the frame portion to the tips of the teeth; and cutting the connecting portion from the watch gear.

[0006] The plate-shaped member is made of a brittle material and comprises a timepiece gear having a plurality of teeth, a frame portion arranged on the outside of the timepiece gear, and a connecting portion which is more flexible than the teeth and connects the frame portion to the tips of the teeth.

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

[0008] The timepiece comprises the above-mentioned timepiece wheel. [Brief description of the drawings]

[0009] [Figure 1] A plan view of the front side of a mechanical watch movement. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a plan view showing the silicon wafer after etching. [Figure 4] An enlarged plan view of a single gear contained within a silicon wafer. [Diagram 5] FIG. [Figure 6] 4 is a flowchart showing a method for manufacturing a gear. [Figure 7] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 8] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 9] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 10] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 11] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 12] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 13] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 14] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 15] 5A to 5C are cross-sectional views illustrating steps in a manufacturing method for a gear. [Figure 16] FIG. 1 is an explanatory diagram showing a schematic configuration of an anisotropic etching apparatus. [Figure 17] 4 is a flowchart showing a manufacturing method of a mechanical watch. [Figure 18] FIG. 11 is an enlarged plan view showing a connection portion according to a modified example. [Figure 19] FIG. 11 is an enlarged plan view showing a connection portion according to a modified example. [Figure 20] FIG. 11 is an enlarged plan view showing a connection portion according to a modified example. [Figure 21] FIG. 11 is an enlarged plan view of one gear included in a silicon wafer according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The timepiece and timepiece wheel of this embodiment, as well as the manufacturing method thereof, will now be described with reference to the drawings. In the following drawings, each layer or member may be shown at a scale different from the actual scale in order to make each layer or member large enough to be recognizable.

[0011] FIG. 1 is a plan view of a movement 10 of a mechanical timepiece 1 as viewed from the front side. In this embodiment, the side where the hands that indicate the time are arranged is the back side, and the side where the spring that drives the hands is arranged is the front side. In Fig. 1, the front side is the front side, and the back side is the back side.

[0012] The mechanical timepiece 1 is made up of a movement 10 shown in Fig. 1 and a casing (not shown) that houses the movement 10. The mechanical timepiece 1 is an example of a timepiece.

[0013] The movement 10 has a main plate 11. The main plate 11 is a plate member for supporting and positioning each component. A dial (not shown) is arranged on the back side of the main plate 11. A wheel train consisting of a plurality of gears is arranged on the front and back sides of the main plate 11. The wheel train arranged on the front side of the main plate 11 is also called the front wheel train, and the wheel train arranged on the back side of the main plate 11 is also called the back wheel train.

[0014] A winding stem guide hole 11a is formed in the main plate 11 in a direction parallel to the main plate 11 from the outer edge toward the center, for guiding a shaft-shaped winding stem 12. The winding stem 12 is incorporated in the winding stem guide hole 11a so as to be movable in the axial direction and rotatable about the axis. A mandrel 13, a yoke 14, a yoke spring 15, and a backing 16 are arranged near the winding stem 12. The mandrel 13, the yoke 14, the yoke spring 15, and the backing 16 constitute a switching mechanism that switches the destination of the rotational force of the winding stem 12.

[0015] The winding stem 12 is inserted through a pinion 17 which is rotatable coaxially with the winding stem 12. A clutch wheel (not shown) which rotates together with the winding stem 12 is disposed on the winding stem 12. The clutch wheel rotates coaxially with the winding stem 12 and can be moved along the axial direction of the winding stem 12 by a switching mechanism. When the winding stem 12 changes position in the axial direction, the switching mechanism switches between a state in which the clutch wheel and the pinion 17 are engaged and a state in which they are not engaged. In addition, a crown wheel 20 which engages with the pinion 17, a ratchet wheel 21 which engages with the crown wheel 20, and a barrel complete 22 which houses a mainspring are rotatably disposed on the main plate 11.

[0016] When the winding stem 12 moves along the axial direction and is positioned at the first winding stem position closest to the center of the movement 10, the clutch wheel and the pinion 17 mesh with each other. When the operator rotates the winding stem 12 in this state, the pinion 17 rotates together with the clutch wheel. The rotation of the pinion 17 rotates the crown wheel 20. The rotation of the crown wheel 20 rotates the ratchet wheel 21. The rotation of the ratchet wheel 21 winds up the mainspring housed in the barrel 22. The mainspring is the power source that drives the movement 10. When the winding stem 12 is positioned at a position outside the first winding stem position, the engagement between the clutch wheel and the pinion 17 is released, and the clutch wheel meshes with a small iron (not shown) for setting the time, etc.

[0017] A center wheel 25, a third wheel 26, and a fourth wheel 27 are rotatably arranged on the main plate 11. The center wheel 25, the third wheel 26, and the fourth wheel 27 each include a gear and a pinion that rotate integrally. The above-mentioned front wheel train is composed of the barrel 22, the center wheel 25, the third wheel 26, and the fourth wheel 27. The front wheel train has the function of transmitting the rotational force of the barrel 22. In addition, an escapement mechanism 30 and a speed regulating mechanism 31 are arranged on the main plate 11 on the front side of the movement 10. The escapement mechanism 30 and the speed regulating mechanism 31 adjust the rotational speed of the front wheel train.

[0018] The pinion of the center wheel & pinion 25 meshes with the barrel wheel 22. A minute hand (not shown) is connected to the center wheel & pinion 25. A gear of the center wheel & pinion 25 meshes with the pinion of the third wheel & pinion 26. A gear of the third wheel & pinion 26 meshes with the pinion of the fourth wheel & pinion 27. A second hand (not shown) is connected to the fourth wheel & pinion 27. The escapement mechanism 30 is a mechanism that controls the rotation of the front wheel train. The escapement mechanism 30 includes an escape wheel 35 and an anchor 36. The escape wheel 35 has a pinion that meshes with the gear of the fourth wheel & pinion 27, and rotates by receiving the torque of the fourth wheel & pinion 27. The anchor 36 rotates the escape wheel 35 regularly according to the operation of the speed-regulating mechanism 31. The speed-regulating mechanism 31 includes a balance 40 that oscillates at a constant cycle, and adjusts the rotation speed of the escape wheel 35 to adjust the rotation speed of the front wheel train that meshes with the escape wheel 35.

[0019] Next, of the various components mentioned above, the third wheel 26 will be described in detail. FIG. 2 is a plan view showing the configuration of the third wheel & pinion 26. As shown in FIG. As shown in FIG. 2, the third wheel 26 includes a gear 50 and a shaft portion 60 that is the rotation axis of the gear 50. The gear 50 is composed of an annular rim portion 52 having a plurality of teeth 51 on its outer circumferential surface, a holding portion 53 through which the shaft portion 60 is inserted, and a plurality of connecting portions 54 that extend radially from the holding portion 53 and connect the rim portion 52 and the holding portion 53. The gear 50 has an opening 50a surrounded by the rim portion 52, the holding portion 53, and two adjacent connecting portions 54. Specifically, the gear 50 has the same number of openings 50a as the connecting portions 54 formed along the circumferential direction. The gear 50 meshes with a pinion 28 (see FIG. 1) provided on the second wheel 27. The gear 50 is an example of a timepiece gear.

[0020] A pinion 61 that meshes with the gear of the center wheel & pinion 25 is formed integrally with the shaft portion 60. The shaft portion 60 is inserted into a hole portion 57 (see FIG. 4) formed in the center of the gear 50 and fixed to the gear 50. Therefore, the gear 50 rotates integrally with the pinion 61.

[0021] The gear 50 is plate-shaped and has a substantially uniform thickness over its 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 in this embodiment is single crystal silicon. Specifically, the gear 50 is formed by etching a silicon wafer made of single crystal silicon. A method for manufacturing the gear 50 will be described later.

[0022] FIG. 3 is a plan view showing the silicon wafer 70 after etching, and FIG. 4 is an enlarged plan view of one gear 50. FIG. 3 and FIG. 4 show an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other. 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 orthogonal to the X-axis. The Z-axis is a coordinate axis orthogonal to the surface of the silicon wafer 70, i.e., the XY plane. Hereinafter, a direction parallel to the XY plane is also called a planar direction, and a direction intersecting the XY plane is also called an intersecting direction.

[0023] As shown in Fig. 3, a silicon wafer 70 is a disk-shaped mother substrate on which multiple gears 50 can be formed. The silicon wafer 70 is an example of a plate-shaped member. On one silicon wafer 70, multiple gears 50 are arranged in a matrix along the X-axis and Y-axis. Each gear 50 is surrounded by a frame 55 that is continuous with the periphery of the silicon wafer 70. In other words, the frame 55 is arranged outside the gears 50.

[0024] In this embodiment, the dimension of the silicon wafer 70 in the direction along the Z axis, i.e., 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. The diameter of a tooth tip circle (not shown), i.e., a circle passing through the tips of the teeth 51, is about 5 mm to 6 mm, and the tooth thickness S (see FIG. 5), i.e., the dimension of the teeth 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.

[0025] The gear 50 is connected to the frame 55 via a connection portion 56. That is, the connection portion 56 connects the gear 50 and 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 tips of two of the teeth 51 of the gear 50. In this embodiment, the angle formed by the extending directions of the two teeth 51 connected by the connection portion 56 is approximately 180°.

[0026] FIG. 5 is an enlarged plan view showing the connection portion 56. As shown in FIG. 5, the connection portion 56 generally extends from the tip of the tooth 51 in substantially the same direction as the extension direction of the tooth 51, and reaches the frame portion 55. In other words, if the end of the connection portion 56 that connects to the tip of the tooth 51 is defined as a first end 56a, and the end that connects to the frame portion 55 is defined as a second end 56b, then the direction D from the first end 56a toward the second end 56b is substantially the same as the extension direction of the tooth 51.

[0027] The shape of the connection portion 56 when viewed along the Z axis is meandering, i.e., wavy. That is, the connection portion 56, in the plan view shown in Fig. 5, faces the direction D while repeatedly bending counterclockwise and clockwise. For this reason, the shape of the connection portion 56 can also be said to be a shape that is alternately bent in opposite directions.

[0028] The width A of the connection portion 56, which corresponds to the line width of the wavy line, is substantially uniform throughout the entire range except for the first end 56a and the second end 56b. In this embodiment, the width A of the connection portion 56 is approximately 30 μm, which is sufficiently smaller than the tooth thickness S of the tooth 51. The first end 56a is constricted. Therefore, the first end 56a has a smaller width than other parts of the connection portion 56. Specifically, the first end 56a is wedge-shaped, and the width becomes smaller toward the tip. In other words, the width B of the tip of the first end 56a is smaller than the width A of the connection portion 56. On the other hand, the width C of the second end 56b is larger than the width A of the connection portion 56.

[0029] The connection 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 since the width A of the connection portion 56 is sufficiently small compared to the tooth thickness S of the teeth 51, the connection portion 56 has a sufficiently high flexibility compared to the teeth 51. From the viewpoint of increasing flexibility, it is desirable that the width A of the connection portion 56 is as small as possible. On the other hand, if the width A of the connection portion 56 is made too small, it becomes difficult to form the connection portion 56 by etching. For this reason, the width A of the connection portion 56 is preferably 10 μm to 50 μm, and more preferably 20 μm to 40 μm.

[0030] The gear 50 connected to the frame 55 via the connecting portion 56 is separated from the silicon wafer 70 by being cut at the first end 56a of the connecting portion 56. Therefore, in the gear 50 after separation, a cut surface 58 is formed at the tip portions of the two teeth 51 that were connected to the connecting portion 56 (see FIG. 2). In other words, the cut surface 58 is the surface that was connected to the first end 56a of the connecting portion 56. The cut surface 58 may protrude outward from the tip portions of the teeth 51, but as long as it protrudes to an extent that it does not come into contact with the pinion 28 of the second wheel 27 with which it meshes, there is no effect on the operation.

[0031] The single crystal silicon, which is the material of the gear 50, has multiple crystal planes and has the property of easily cleaving at the crystal planes. In other words, single crystal silicon can be cut with less force when cut along the crystal planes than when cut along planes other than the crystal planes. Furthermore, when cutting along the crystal planes, cracks caused by cutting are prevented from spreading in directions other than the crystal planes. For this reason, it is preferable that both the front and back surfaces of the gear 50 parallel to the XY plane and the two cut surfaces 58 connected to the connection part 56 are crystal planes.

[0032] Next, a manufacturing method of the gear 50 provided on the third wheel 26 will be described. FIG. 6 is a flow chart showing a method for manufacturing gear 50, and FIGS. 7 to 15 are cross-sectional views illustrating the steps of the method for manufacturing gear 50. 6, the method for manufacturing gear 50 includes steps S1 to S6. That is, gear 50 is manufactured by sequentially performing steps S1 to S6.

[0033] Step S1 is an oxide film forming step. As shown in Fig. 7, this step is a step of forming a silicon oxide film 71 on one flat surface of a silicon wafer 70. The silicon wafer 70 is ground in advance to an appropriate thickness and the surface is polished so that the tooth width of the gear 50 has a desired dimension.

[0034] The silicon wafer 70 has two flat surfaces, a first surface 70a and a second surface 70b, on the front and back sides. In step S1, a silicon oxide film 71 is formed on the second surface 70b. The silicon oxide film 71 is formed by a chemical vapor deposition (CVD) method. The thickness of the silicon oxide film 71 is not particularly limited, but is, for example, about 1 μm. The silicon oxide film 71 is formed to prevent holes 70c formed in an etching process in step S4, which will be described later, from penetrating from the front to the back side.

[0035] Step S2 is a photoresist coating step. As shown in FIG. 8, this step is a step of forming a resist film 72 on a first surface 70a of a 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 a spin coating method, a spray coating method, or the like. Next, the resin solution is dried to remove the solvent, thereby forming the resist film 72. Either a negative type or a positive type material may be used for the photosensitive resin.

[0036] Step S3 is an exposure and development step. This step is a step of forming an etching mask for forming gears 50. First, resist film 72 is exposed to light using a photomask on which a pattern corresponding to multiple gears 50, frame portion 55, and multiple connection portions 56 connecting these gears, as shown in FIG. 3, is formed. After that, development is performed to remove unnecessary resist film 72, and openings 72a corresponding to the pattern of the photomask are formed in resist film 72, as shown in FIG. 9. Openings 72a correspond to portions where silicon is removed from silicon wafer 70 by etching. In other words, resist film 72 with openings 72a formed therein functions as an etching mask.

[0037] Step S4 is an etching process. In this process, the silicon wafer 70 is etched using the resist film 72 as an etching mask to form the shapes of the gear 50, the frame portion 55, and the connection portion 56. For the etching, for example, anisotropic etching such as deep reactive ion etching (DRIE) using inductively coupled plasma (ICP) is used.

[0038] FIG. 16 is an explanatory diagram showing a schematic configuration of an anisotropic etching apparatus 81 that performs DRIE using ICP. As shown in FIG. 16, the anisotropic etching apparatus 81 includes a stage 82 and a coil 83. The silicon wafer 70 is placed on the stage 82 so that the first surface 70a on which the resist film 72 is formed faces the coil 83. The anisotropic etching apparatus 81 generates plasma 84 by supplying SF6 gas and passing a large current of high frequency through the coil 83. When a bias is applied to the stage 82, particles of the plasma 84 are drawn from the openings 72a of the resist film 72 to the first surface 70a of the silicon wafer 70. As a result, the silicon wafer 70 is etched from the first surface 70a side in the shape of the openings 72a and approximately perpendicular to the intersecting direction. The etched silicon becomes SiF4 and is removed. In order to prevent the silicon wafer 70 from overheating, the anisotropic etching apparatus 81 cools the silicon wafer 70 from the second surface 70b side using, for example, helium gas.

[0039] As shown in Fig. 10, when the silicon wafer 70 is shaved to a predetermined depth, an 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, as shown in Fig. 11. The formation of the protective film 85 is also called coating.

[0040] Thereafter, the anisotropic etching apparatus 81 etches the silicon wafer 70 again to expose the silicon, as shown in FIG. 12, and then coats the silicon wafer 70 with the protective film 85 again, as shown in FIG. 13. In this manner, the anisotropic etching apparatus 81 repeats the etching of the silicon wafer 70 and the coating of the protective film 85 multiple times. This method is called the Bosch process. By this Bosch process, holes 70c reaching the silicon oxide film 71 are formed in the silicon wafer 70 in the areas not covered with the resist film 72, as shown in FIG. 14. Here, the holes 70c include the gap between the gear 50 and the frame 55, and the openings 50a and holes 57 formed in the gear 50.

[0041] Step S5 is an oxide film removal process. This process is a process for removing a silicon oxide film 71 and a resist film 72 disposed on a silicon wafer 70, as shown in Fig. 15. The resist film 72 can be removed by wet etching using fuming nitric acid or an organic solvent capable of dissolving and peeling off the resist film 72, or by oxygen plasma ashing. In this embodiment, after ashing by oxygen plasma ashing, the residue is further removed using an organic remover.

[0042] 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. The silicon oxide film 71 may also be removed by reactive ion etching using parallel plates.

[0043] As described above, steps S1 to S5 form the multiple gears 50, frame 55, and multiple connecting portions 56 connecting them, as shown in Fig. 3. In other words, the series of processes including steps S1 to S5 is an external shape forming process in which silicon wafer 70 is etched to form gears 50, frame 55, and connecting portions 56.

[0044] Step S6 is a cutting step. This step is a step of cutting the connection part 56 and the gear 50. The work of cutting the connection part 56 and the gear 50 is performed using a tool with a thin tip such as tweezers. Specifically, the worker places the silicon wafer 70 shown in FIG. 3 and FIG. 4 on a workbench (not shown) and fixes the frame part 55 on the workbench. Then, the worker inserts a tool into the opening 50a in the gear 50 and displaces the gear 50 in a planar direction while bringing the tool into contact with the opening 50a. That is, the gear 50 is displaced in a planar direction relative to the frame part 55 by the tool. At this time, the first end 56a of the connection part 56 is also displaced following the displacement of the gear 50, but the connection part 56 is bent due to its flexibility and does not break in the middle of the connection part 56. Then, when the force acting on the first end 56a reaches a predetermined value, the first end 56a breaks and the connection part 56 and the gear 50 are cut off.

[0045] In step S6, gear 50 is separated from silicon wafer 70, and gear 50 is completed. That is, gear 50 is produced by being cut from silicon wafer 70. Then, cut surfaces 58 are formed at the tips of two teeth 51 to which connecting parts 56 were connected when the gear 50 is cut from silicon wafer 70. Therefore, the multiple teeth 51 of gear 50 include two teeth 51 having cut surfaces 58 at their tips.

[0046] The two connection parts 56 may be cut one by one, or the two connection parts 56 may be cut in one operation. For example, if a shaft is inserted into the central hole 57 of the gear 50 and the gear 50 is rotated around this shaft, it becomes easy to cut the two connection parts 56 in one operation. Furthermore, the direction in which the gear 50 is displaced is not limited to the planar direction, and the connection parts 56 may be cut by displacing the gear 50 in an intersecting direction.

[0047] Next, a method for manufacturing the mechanical timepiece 1 will be described. FIG. 17 is a flow chart showing a method for manufacturing the mechanical timepiece 1. 17, the method for manufacturing the mechanical timepiece 1 includes steps S11 to S13. In other words, the mechanical timepiece 1 is manufactured by carrying out steps S11 to S13 in order.

[0048] Step S11 is a parts assembly process, which is a process for assembling the various parts that make up the mechanical timepiece 1. For example, the third wheel 26, which is one of the parts, is assembled by inserting the shaft portion 60 into the hole portion 57 of the gear 50 formed by the above steps S1 to S6. Assembly is also carried out for parts other than the third wheel 26 as necessary.

[0049] Step S12 is a movement assembly process, which is a process for assembling the movement 10. This process includes a process for attaching various parts such as the third wheel 26 to the main plate 11.

[0050] Step S13 is a watch assembly process, which is a process for assembling the mechanical watch 1. This process includes a process for housing the movement 10 in a casing (not shown). Through the above processes, the mechanical watch 1 is completed.

[0051] As described above, the gear 50 of this embodiment and the manufacturing method thereof can provide the following effects.

[0052] According to this embodiment, since the connection portion 56 is connected to the tip portion of the tooth 51, it is possible to connect the connection portion 56 to the gear 50 even if the interval between the teeth 51 is small. Also, since the connection portion 56 is connected to the tip portion of the tooth 51, it is possible to prevent the cut surface 58 after the connection portion 56 is cut from affecting the meshing with other gears.

[0053] In addition, when the flexible connection portion 56 is connected between the teeth 51, it is possible that the bent connection portion 56 may come into contact with the tooth 51 in the cutting process of step S6. In this case, there is a risk that the connection portion 56 may break midway or damage the tooth 51. In contrast, in this embodiment, the connection portion 56 is connected to the tip portion of the tooth 51, so that it is possible to prevent the connection portion 56 from breaking midway or damage the tooth 51 in the cutting process.

[0054] Furthermore, when the connection portion 56 is connected between the teeth 51, the etching pattern becomes dense around the connection portion 56. As a result, there is a risk that a difference will occur between the shape of the teeth 51 around the connection portion 56 and the shape of the other teeth 51 due to a microloading effect. In contrast, in this embodiment, the connection portion 56 is connected to the tip portion of the tooth 51, so that the etching pattern is prevented from becoming locally dense, and it is possible to prevent differences in the shape of the teeth 51.

[0055] Furthermore, according to this embodiment, since the connecting portion 56 has a wavy shape, the connecting portion 56 can be bent to a greater extent than if it were straight.

[0056] Furthermore, according to this embodiment, a constriction is formed in the first end 56a of the connection portion 56. In other words, the first end 56a is thinner than other portions of the connection portion 56, and therefore, when cutting the connection portion 56 and the gear 50, it is easy to cut them at the first end 56a.

[0057] Furthermore, according to this embodiment, in the cutting process of step S6, when displacing the gear 50, the tool is brought into contact with the opening 50a, not with the teeth 51. In this way, since the tool is brought into contact with a portion other than the teeth 51 during cutting, damage to the teeth 51 by the tool can be suppressed.

[0058] Furthermore, by using silicon wafer 70 in a state in which the outer diameters of gear 50, frame portion 55, and connecting portion 56 have been formed after the outer shape forming process of this embodiment, gear 50 having the above-mentioned effects can be easily formed.

[0059] Furthermore, according to the mechanical timepiece 1 of this embodiment, the gear 50 that provides the effects described above is used, making it possible to achieve stable operation.

[0060] The above embodiment may be modified as follows.

[0061] In the above embodiment, the shape of the connection portion 56 is a wavy line, but the number of waves in the wavy line and the amplitude of the waves are not limited to the embodiment shown in FIG. 5. For example, as shown in FIG. 18, the number of waves may be smaller, or as shown in FIG. 19, the amplitude of the waves may be larger. The shape shown in FIG. 19 can be rephrased as a shape in which linear portions are alternately bent in opposite directions, or a shape in which linear portions parallel to the XY plane and along a direction intersecting the direction D are alternately bent in opposite directions toward the direction D. The shape of the connection portion 56 is not limited to a wavy line, and may be a curved shape different from the wavy line, as shown in FIG. 20. In this way, the connection portion 56 is not particularly limited as long as it can follow the displacement of the gear 50 in the planar direction to some extent due to its flexibility.

[0062] In the above embodiment, two connection parts 56 are connected to each gear 50, and the angle formed by the extension directions of the two teeth 51 connected by the connection parts 56 is approximately 180°, but is not limited to this. For example, as shown in FIG. 21, the angle formed by the extension directions of the two teeth 51 connected by the connection parts 56 may be approximately 90° or another angle. In addition, the number of connection parts 56 is not limited to two, and may be one, or three or more. In addition, in a configuration in which multiple connection parts 56 are connected to one gear 50, the shapes and dimensions of the multiple connection parts 56 may be the same or different.

[0063] In the above embodiment, the direction D from the first end 56a to the second end 56b of the connection portion 56 is approximately the same as the extension direction of the tooth 51 to which the connection portion 56 is connected, but the direction D may be a direction different from the extension direction of the tooth 51.

[0064] In the above embodiment, when the hole 70c is formed by the Bosch process in the etching process of step S4, irregularities called scallops are formed on the etched surface. A process for removing the scallops may be additionally performed. This process may be, for example, a process in which an oxide film having a depth of 1 μm or more is formed on the silicon wafer 70 by thermal oxidation, and then the oxide film is etched by immersing the silicon wafer 70 in a BHF solution.

[0065] In the above embodiment, after the shaft portion 60 is inserted into the gear 50 in the parts assembly process of step S11, an oxidation treatment may be performed to form a silicon oxide film made of silicon dioxide (SiO2) on the surface of the gear 50. When the oxidation treatment is performed on the gear 50, the silicon oxide film formed on the surface of the gear 50 made of a material containing silicon improves the mechanical strength of the gear 50. When the oxidation treatment is performed, it is preferable to use a thermal oxidation treatment performed at a high temperature of, for example, 1000°C or higher.

[0066] In the above embodiment, silicon, which is a plate-shaped brittle material, is used as the material of the gear 50, but the material of the gear 50 is not limited to silicon. For example, silicon carbide, quartz crystal, glass, sapphire, etc. may be used.

[0067] In the above embodiment, the gear 50 of the third wheel 26 that constitutes 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 that constitute the front wheel train and gears that constitute the back wheel train. Furthermore, the timepiece is not limited to the mechanical timepiece 1, and may 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, etc. [Explanation of symbols]

[0068] 1...mechanical watch, 10...movement, 11...main plate, 11a...winding stem guide hole, 12...winding stem, 13...lovebird, 14...bolt, 15...bolt spring, 16...back, 17...wheel, 20...crown wheel, 21...rake wheel, 22...barrel, 25...second wheel, 26...third wheel, 27...fourth wheel, 30...escapement mechanism, 31...governing mechanism, 35...escape wheel, 36...ankle, 40...balance, 50...gear, 50a...opening, 51...teeth, 52...rim, 53... Holding portion, 54...connecting portion, 55...frame portion, 56...connecting portion, 56a...first end, 56b...second end, 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...resist film, 72a...opening, 81...anisotropic etching apparatus, 82...stage, 83...coil, 84...plasma, 85...protective film, A,B,C...width, D...direction, P...pitch circle, S...tooth thickness.

Claims

1. A process of forming a timepiece wheel having a plurality of teeth, a frame portion disposed on the outside of the timepiece wheel, and a connecting portion that is more flexible than the teeth and connects the frame portion and the tip portion of the teeth by etching a plate-shaped member made of a brittle material; cutting the connection portion and the timepiece wheel; A method for manufacturing a timepiece wheel, comprising:

2. A method for producing a timepiece wheel according to claim 1, comprising the steps of:

13. A method for manufacturing a timepiece wheel, comprising the steps of: forming a first connecting portion and a second connecting portion in a first direction such that the first connecting portion is in a first direction;

3. A method for producing a timepiece wheel according to claim 1, comprising the steps of:

13. A method for manufacturing a timepiece wheel, comprising the steps of: forming a groove in the groove for receiving a tooth; forming a groove in the groove for receiving a tooth;

4. A method for producing a timepiece wheel according to claim 1, comprising the steps of:

13. A method for manufacturing a timepiece wheel, comprising the steps of: forming a connecting portion having a width smaller than a thickness of the teeth; and forming a connecting portion having a shape in which straight line portions are alternately bent in opposite directions.

5. A method for producing a timepiece wheel according to claim 1, comprising the steps of: A method for manufacturing a timepiece wheel, wherein the connecting portion has a constriction formed at an end portion which connects to the tip portion of the tooth.

6. A method for producing a timepiece wheel according to claim 1, comprising the steps of: the step of cutting the connection portion and the timepiece wheel includes cutting the connection portion and the timepiece wheel by displacing the timepiece wheel with respect to the frame portion using a tool; A method for manufacturing a timepiece wheel, wherein the tool comes into contact with a portion of the timepiece wheel other than the teeth.

7. A plate-like member made of a brittle material, a time wheel having a plurality of teeth; a frame portion disposed on the outside of the timepiece wheel; a connection portion that is more flexible than the teeth and connects the frame portion and the tip portion of the teeth; A plate-like member comprising:

8. A timepiece wheel having a plurality of teeth, the timepiece wheel being produced by cutting a plate-shaped member made of a brittle material, A timepiece wheel, wherein the plurality of teeth include a tooth having a cut surface at a tip thereof that is formed when the tooth is cut from the plate-shaped member.

9. A timepiece comprising a time wheel according to claim 8.

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