JP2018179788A - Mechanical component, timepiece, and manufacturing method for mechanical component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical component capable of achieving improvement of accuracy of a timepiece while achieving improvement of quality and productivity of the mechanical component by suppressing occurrence of cracks of a corner part when a holding part of a rotary member holds a shaft member and making frictional force between the other mechanical component meshing with a tooth of the rotary member and itself, and the timepiece using the mechanical component and a manufacturing method for the mechanical component.SOLUTION: An escapement wheel serving as a mechanical component comprises: a shaft member; a holding part 115 holding the shaft member; and an escapement gear part 101 serving as a rotary member having a rim part 111 having a plurality of tooth parts 114. Each cross-sectional shape of corner parts 112a of a plurality of curved parts 112 constituting the holding part 115 and corner parts 114a of the tooth parts 114 is formed into an arc shape.SELECTED DRAWING: Figure 6

Description

  The present invention relates to machine parts, watches, and methods of manufacturing machine parts.

  A mechanical watch is mounted with many mechanical parts represented by gears and the like. A mechanical component such as a gear is configured such that a shaft member is inserted and fixed (held) in a through hole (holding portion) provided at the center of a rotating member having a plurality of teeth formed on the outer periphery. Conventionally, mechanical parts are formed by machining a metal material, but in recent years, a base material containing silicon has been used as a material of mechanical parts for watches. Since the mechanical component based on silicon is lighter than that based on metal, it is possible to reduce the inertia force of the mechanical component, and thus it is expected to improve the energy transfer efficiency. In addition, since silicon has a high degree of freedom in the shape formed using photolithography and etching technology, there is an advantage that processing accuracy of mechanical parts can be improved by using silicon as a base material.

  Patent Document 1 discloses a method for manufacturing a mechanical part for a watch by etching an SOI substrate having an oxide film layer between two silicon layers. In the method of Patent Document 1, a mask is formed in the shape of a mechanical component on one silicon layer of an SOI substrate, and the silicon layer is deeply etched using the oxide film layer as an etching stopper to form the shape of the mechanical component. Then, the other silicon layer and the oxide film layer are removed to separate the mechanical parts. According to such a method, it is supposed that machine parts can be manufactured with high precision as the shape of the mask.

JP, 2016-133495, A

  By the way, in the case of forming a rotating member having a holding portion for holding a shaft member and a rim portion having a tooth portion as a mechanical part for a watch by the method of manufacturing a mechanical part described in Patent Document 1, The portion without the mask is removed vertically through the silicon layer by deep etching. Therefore, the cross-sectional shape of the corner where the front and back surfaces of the formed rotating member intersect with the end surface becomes a shape close to a right angle. Then, when the shaft member is fitted into the holding portion of the rotating member, there is a possibility that the corner of the holding portion may be chipped. If the corner of the holding portion is chipped, the quality and productivity of the rotating member may be reduced. In addition, when the corner portion has such a shape, there is a possibility that the frictional force between other teeth of the rotating member and other mechanical parts meshing with the teeth may be increased. When the frictional force becomes large, the resistance to the rotation of the rotating member becomes large and the energy transmission efficiency is lowered, which causes the precision of the timepiece to be lowered.

  The present invention has been made to solve at least a part of the above-described problems, and can be realized as the following modes or application examples.

  Application Example 1 A mechanical component according to this application example includes a rotating member having a shaft member, a holding portion for holding the shaft member, and a rim portion having a plurality of tooth portions, and the holding portion The cross-sectional shapes of the corner of the tooth and the corner of the tooth are both formed in an arc shape.

  According to the configuration of the mechanical component of this application example, since the cross-sectional shape of the corner of the holder in the rotary member is formed in an arc shape, when inserting the shaft member into the holder of the rotary member, As compared with the case where the cross-sectional shape is not a circular arc, the occurrence of chipping at the corner is suppressed. Thereby, the quality and productivity of machine parts can be improved. In addition, since the cross-sectional shape of the corner of the tooth portion in the rotating member is formed in an arc shape, it is between the other mechanical parts meshing with the teeth of the rotating member as compared with the case where the cross-sectional shape of the corner The friction force of Thereby, the resistance to the rotation of the rotating member can be reduced, and the energy transfer efficiency is improved, so that the accuracy of the timepiece can be improved.

  Application Example 2 In the machine component according to the application example described above, the corner portion formed in the arc shape intersects one surface of the rotating member, the end surface of the holding portion, and the end surface of the tooth portion. Preferably, it is formed at the corner.

  According to the configuration of the mechanical component of this application example, since the corner where one surface of the rotating member intersects with the end surface of the holding portion is formed in an arc shape, the one side of the rotating member from the one surface side When inserting the shaft member along the end face, the occurrence of chipping of the corner of the holding portion can be suppressed. Further, since the corner where one surface of the rotating member intersects the end surface of the tooth portion is formed in an arc shape, the end surface of the rotating member teeth and the end surface of another mechanical component meshing with the rotating member teeth The frictional force between can be reduced.

  Application Example 3 In the machine component according to the application example, it is preferable that the arc-shaped corner of the holding portion and the arc-shaped corner of the tooth have the same shape.

  According to the configuration of the mechanical component of this application example, the arc-shaped corner of the holder and the arc-shaped corner of the tooth can be formed in the same etching step.

  Application Example 4 In the machine component according to the application example described above, the shaft member may have an overhanging portion in a region fitted with the arc-shaped corner portion of the holding portion.

  When the shaft member has an overhanging portion in a region fitted with the arc-shaped corner portion of the holding portion, the shaft is held by the holding portion when the corner portion of the holding portion is not arc-shaped. The overhanging portion of the member and the corner of the holding portion interfere with each other. According to the configuration of the mechanical component of this application example, since the corner of the holder is arc-shaped, interference between the overhang of the shaft member and the corner of the holder can be alleviated. As a result, even if the shaft member has the overhanging portion in the area where it fits with the arc-shaped corner of the holding portion, the shaft member can be easily inserted into the holding portion.

  Application Example 5 A timepiece according to this application example includes the mechanical component described above.

  According to the configuration of the timepiece of this application example, since the mechanical component described in any of the above-mentioned application examples is provided, it is possible to provide a high quality timepiece with high accuracy.

  Application Example 6 In the method of manufacturing a mechanical component according to this application example, the one surface of the substrate is anisotropically etched along the shape of the mechanical component leaving a part in the thickness direction of the substrate; And D. Isotropically etching the other surface of the substrate to separate the mechanical component.

  According to the method of manufacturing a mechanical component of this application example, when a plurality of mechanical components are manufactured from a single substrate by performing anisotropic etching leaving a part in the thickness direction of the substrate, the machine from the substrate is machined. It is possible to form a machine component shape by digging one surface of the substrate without separating the components. Then, by isotropically etching the other surface of the substrate, a part of the substrate in the thickness direction left in the anisotropic etching process can be removed to separate the mechanical component from the substrate.

  Application Example 7 In the method of manufacturing a mechanical component according to the application example described above, in the step of separating the mechanical component, the isotropic etching is performed more than the time for removing a part in the thickness direction of the substrate. It is preferable to apply for a long time.

  According to the method of manufacturing a mechanical component of this application example, in the step of separating the mechanical component, the isotropy is longer than the time for removing a part of the substrate left in the anisotropic etching step in the thickness direction. By applying the etching, corner portions of each portion of the mechanical component on the side to be isotropically etched can be formed in an arc shape.

The top view of the front side of the movement of the mechanical timepiece which concerns on this embodiment. The top view of the escapement mechanism which concerns on this embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The perspective view of the escape wheel as a mechanical component which concerns on this embodiment. FIG. 3 is a cross-sectional view taken along the line A-A ′ of FIG. 2; The top view of the escape gear part as a rotation member which concerns on this embodiment. Sectional drawing of the escape gear part which concerns on this embodiment. The fragmentary sectional view which expanded the curved part of FIG. The fragmentary sectional view which expanded C section of FIG. The fragmentary sectional view which meets the B-B 'line of FIG. The flowchart which shows the manufacturing method of the escape wheel which concerns on this embodiment. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. Schematic sectional drawing which shows the manufacturing method of an escape wheel. The schematic diagram which shows an example of schematic structure of an anisotropic etching apparatus. The schematic diagram which shows an example of schematic structure of an isotropic etching apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a mechanical watch is taken as an example of the watch of the present invention. Then, as an example of the mechanical component of the present invention, an escape wheel, which is one of the gears constituting the timepiece component in the movement of the mechanical timepiece, will be described as an example. In each of the following drawings, in order to make each layer and each member have a recognizable size, each layer and each member may be shown on a scale different from the actual scale.

(Embodiment 1)
[Mechanical watch]
First, a mechanical timepiece 1 as a timepiece according to the present embodiment will be described. FIG. 1 is a plan view of the front side of the movement of the mechanical timepiece according to the present embodiment. As shown in FIG. 1, the mechanical timepiece 1 according to the present embodiment is constituted by a movement 10 and a casing (not shown) for housing the movement 10.

  The front side of the paper surface in FIG. 1 is called front side, and the back side is called back side. The movement 10 has a main plate 11 that constitutes a substrate. On the back side of the base plate 11, a dial plate (not shown) is disposed. A train wheel incorporated on the front side of the movement 10 is referred to as a front train wheel, and a train wheel incorporated on the back side of the movement 10 is referred to as a back train wheel.

  A winding stem guide hole 11a is formed in the base plate 11, and the winding stem 12 is rotatably incorporated in the winding stem guide hole 11a. The axial position of the winding stem 12 is determined by a switching device having a setting lever 13, a yoke 14, a clamping spring 15 and a back retainer 16. Further, on the guide shaft portion of the winding stem 12, a cutting wheel 17 is rotatably provided.

  Under such a configuration, the winding stem 12 is rotated while the winding stem 12 is in the first winding position (0th step) closest to the inside of the movement 10 along the rotation axis direction. The transmission wheel 17 rotates through the rotation of a drive wheel (not shown). And, by the rotation of the wheel 17, the crown wheel 20 meshing with the wheel 17 is rotated. Then, by the rotation of the round crown 20, the square center wheel 21 engaged with the round crown 20 is rotated. Furthermore, when the ratchet wheel 21 rotates, the unshown mainspring (power source) accommodated in the barrel 22 is wound up.

  The front train wheel of the movement 10 includes, in addition to the above-mentioned barrel car (machine part) 22, a second wheel (machine part) 25 called a so-called wheel wheel, a third wheel (machine part) 26, and a fourth wheel (machine Component 27 and functions to transmit the rotational force of the barrel 22. Further, on the front side of the movement 10, an escapement mechanism 30 and a speed control mechanism 31 for controlling the rotation of the front train wheel are disposed.

  The second wheel & pinion 25 is a gear that meshes with the barrel wheel 22. The third wheel & pinion 26 is a gear that meshes with the second wheel & pinion 25. The fourth wheel 27 is a gear that meshes with the third wheel 26. The escapement mechanism 30 is a mechanism that controls the rotation of the front wheel train described above, and escapes the escape wheel (machine part) 35 and the escape wheel 35 that mesh with the fourth wheel 27 and rotates regularly. And an ankle (machine part) 36. The speed control mechanism 31 is a mechanism that controls the escapement mechanism 30 described above, and includes a balance (machine part) 40.

<Gauntlet car>
Next, the escape wheel 35 provided in the escapement mechanism 30 according to the present embodiment will be described in more detail. FIG. 2 is a plan view of the escapement mechanism according to the present embodiment. FIG. 3 is a perspective view of an escape wheel as a mechanical component according to the present embodiment. FIG. 4 is a cross-sectional view taken along the line AA 'of FIG. FIG. 5 is a plan view of an escape gear portion as a rotating member according to the present embodiment.

  As shown in FIGS. 2 to 4, the escape wheel 35 provided in the escapement mechanism 30 is coaxially fixed to the escape gear portion 101 as a rotating member and coaxial with the escape gear portion 101 (axis O1). And a shaft member (rotational shaft) 102. In the following description, the direction along the axis O1 of the bevel gear portion 101 and the shaft member 102 is simply referred to as the axial direction, the direction orthogonal to the axis O1 is referred to as the radial direction, and the direction circling around the axis O1 is the circumferential direction. It is said. Further, in the radial direction, the axis O1 side is referred to as an inner peripheral side, and the side opposite to the axis O1 side is referred to as an outer peripheral side.

  As shown in FIGS. 2 to 5, in the bevel gear portion 101, a surface 101a as one surface and a back surface 101b as the other surface opposite to the one surface are flat surfaces. It is a plate-like thing made uniform thickness over the whole surface. The escape gear portion 101 is made of a material having a crystal orientation, such as single crystal silicon, or a material such as metal.

  The escape gear portion 101 has a peripheral rim portion 111, a central holding portion 115, and a plurality of spoke-like elastic portions 113 connecting the rim portion 111 and the holding portion 115. On the outer peripheral surface of the rim portion 111, a plurality of tooth portions 114 formed in a special bowl shape are provided protruding outward in the radial direction. Toe stones 144a and 144b of an ankle 36, which will be described later, are in contact with the tips of the plurality of teeth 114.

  As shown in FIGS. 3 to 5, the holding portion 115 has a plurality of curved portions 112 which are formed so as to be bent and projected into the through hole through which the shaft member 102 is inserted. The holding portion 115 according to the present embodiment has three curved portions 112, and the shaft member 102 is held by these curved portions 112.

  Each elastic portion 113 radially extends in a circular arc shape branched into two toward the inner peripheral edge of the rim portion 111 from between the adjacent curved portions 112 in the holding portion 115, and the rim portion 111 and the holding portion And 115 are linked.

  As shown in FIGS. 3 and 4, the shaft member 102 is engaged with the tenon portions 121a and 121b located at both ends in the axial direction and the gear portion of the fourth wheel 27 (see FIG. 1) described above. And a sharp portion 122. Of the tenon portions 121a and 121b, one end tenon portion 121a positioned on one end side in the axial direction is rotatably supported by a train wheel bridge (not shown), and the other end tenon portion 121b positioned on the other end side in the axial direction is It is rotatably supported by the main plate 11 described above.

  The end 122 is formed at one end near the tenon portion 121 a in the shaft member 102. Then, the on-gear portion 122 is engaged with the fourth wheel 27 to transmit the rotational force of the fourth wheel 27 to the shaft member 102, thereby rotating the escape wheel 35.

  The press-fit shaft portion 123 is formed to have a diameter larger than that of the tenon portions 121a and 121b described above. The press-fit shaft portion 123 is inserted from the side of the back surface 101 b into the through hole in which the plurality of curved portions 112 are disposed in the holding portion 115 (see FIG. 3) of the escape gear portion 101. In this case, the press-fit shaft portion 123 is disposed in the holding portion 115 in a state where a part thereof protrudes from the surface 101 a of the escape gear portion 101 toward the other axial end side.

  Further, in the shaft member 102, a flange portion 124 that protrudes outward in the radial direction is formed between the sharp end portion 122 and the press-fit shaft portion 123. The diameter of the flange portion 124 is larger than the opening of the inscribed circle passing through the tops of the three curved portions 112 protruding into the through hole of the holding portion 115. The end surface located on the other end side in the axial direction of the flange portion 124 is in contact with the back surface 101 b of the curved portion 112.

  Here, the diameter of the inscribed circle passing through the tops of the three curved portions 112 protruding into the through hole of the holding portion 115 is the press-fit shaft of the shaft member 102 in the state where the shaft member 102 is not inserted into the through hole. The section 123 is designed to be smaller than the diameter of a cross section taken in a direction orthogonal to the axis O1.

  As shown in FIG. 2, the plurality of teeth 114 of the escape wheel 35 are engaged with the ankle 36. The ankle 36 includes an ankle body 142 d formed in a T-shape by three ankle beams 143 and an ankle true 142 f as an axis. The ankle body 142d is configured to be pivotable by an ankle true 142f. In addition, the ankle true 142f is rotatably supported at the both ends thereof with respect to the main plate 11 and the ankle receiver (not shown) described above.

  Of the three ankle beams 143, toe stones 144a and 144b are provided at the tips of two ankle beams 143, and an ankle jack 145 is attached to the tip of the remaining one ankle beam 143. The toe stones 144a and 144b are rubies formed in a square pole shape, and are adhesively fixed to the ankle beam 143 by an adhesive or the like.

  When the ankle 36 configured as described above is rotated about the ankle true 142f, the toe stone 144a or 144b comes in contact with the tip of the tooth portion 114 of the escape wheel 35. Also, at this time, the ankle beam 143 to which the ankle jack 145 is attached contacts a dote pin (not shown), whereby the ankle 36 is prevented from rotating in the same direction any more. As a result, the rotation of the escape wheel 35 is also temporarily stopped.

  Next, the cross-sectional shape of the escape gear portion 101 according to the present embodiment will be described. FIG. 6 is a cross-sectional view of an escape gear portion according to the present embodiment. Specifically, FIG. 6 is a partial cross-sectional view in which a portion on the right side of the axis line O1 in the on-gear portion 101 shown in FIG. 4 is enlarged. FIG. 7 is an enlarged partial sectional view of the curved portion of FIG. FIG. 8 is an enlarged partial sectional view of a portion C of FIG. FIG. 9 is a partial cross-sectional view taken along the line B-B 'of FIG.

  As shown in FIG. 6, in the escape gear portion 101 according to the present embodiment, the curved portion 112 (holding portion 115) and the tooth portion 114 have the corner portion 112a and the corner portion 114a on the back surface 101b side, respectively. doing. The cross-sectional shapes of the corner portion 112 a of the curved portion 112 (holding portion 115) and the corner portion 114 a of the tooth portion 114 are both formed in an arc shape.

  The corner portion 112 a formed in an arc shape is formed at a corner portion where the back surface 101 b of the bevel gear portion 101 and the end surface of the bending portion 112 intersect. Here, the end surface is a surface along the axial direction, that is, a surface along the thickness direction of the escape gear portion 101. The inner circumferential side end face 112 b of the curved portion 112 is an end face in contact with the shaft member 102 (see FIG. 4) inserted into the through hole of the holding portion 115. The curved portion 112 has a corner portion 112a formed in an arc shape on the inner end face 112b and the outer end face.

  The corner portion 114 a formed in an arc shape is formed at a corner portion where the back surface 101 b of the bevel gear portion 101 and the outer peripheral side end surface 114 b of the tooth portion 114 intersect. Further, in the escape gear portion 101 according to the present embodiment, a corner portion where the back surface 101b intersects the inner peripheral side end surface of the rim portion 111 and a corner portion where the rear surface 101b intersects the outer peripheral side end surface of the rim portion 111 Also, arc-shaped corner portions 111a are formed. The arc-shaped corner 112 a of the curved portion 112, the arc-shaped corner 114 a of the tooth 114 and the arc-shaped corner 111 a of the rim 111 have the same shape. In the present specification, the same shape takes into consideration variations in processing accuracy and the like, and refers to a shape that can be recognized as substantially the same shape by those skilled in the art.

  As shown in FIG. 7, the thickness of the center gear portion 101 is T1. In the present embodiment, the thickness T1 of the escape gear portion 101 is, for example, about 120 μm. In the thickness direction of the escape gear portion 101, that is, in the axial direction, the length of the portion where the corner portion 112a of the curved portion 112 is formed in an arc shape is C1. In the radial direction of the escape gear portion 101, the length of the portion where the corner portion 112a of the curved portion 112 is formed in an arc shape is C2. In the present embodiment, the lengths C1 and C2 of the arc-shaped portions are, for example, about 10 μm. The corner portion 114a of the tooth portion 114 and the corner portion 111a of the rim portion 111 are also formed in an arc shape with similar lengths C1 and C2.

  As shown in FIG. 8, in the press-fit shaft portion 123 of the shaft member 102, an arc-shaped corner portion 112 a is formed in the through hole in which the plurality of curved portions 112 are arranged in the holding portion 115 of the escape gear portion 101. It is inserted from the side of the back surface 101b. The shaft member 102 is in contact with the inner circumferential end surface 112 b at the top of the curved portion 112 that projects into the through hole so as to press the shaft member 102.

  Further, in the shaft member 102, the corner portion 125 of the press-fit shaft portion 123 and the flange portion 124 protruding toward the outer peripheral side in the radial direction with respect to the press-fit shaft portion 123 is a curved portion of the offset gear portion 101. This is an area to be fitted with the arc-shaped corner portion 112 a of 112 (holding portion 115). In the present embodiment, the shaft member 102 has the overhanging portion 125 a at the corner 125 where the shaft member 102 is fitted with the corner 112 a of the curved portion 112. The overhanging portion 125a is opposed to the arc-shaped corner portion 112a, and the cross section thereof is formed in an arc shape so as to be recessed toward the corner portion 125 side.

  Here, it is assumed that the corner 112a of the curved portion 112 of the escape gear portion 101 is not arc-shaped but is, for example, a right angle. As described above, the diameter of the inscribed circle passing through the tops of the three curved portions 112 protruding into the through hole of the holding portion 115 is designed to be smaller than the diameter of the press-fit shaft portion 123 of the shaft member 102 (see FIG. 3 and FIG. 4). Therefore, in the process of manufacturing the escape wheel 35, which will be described later, the shaft member 102 is inserted so as to spread the inner end face 112b of the curved portion 112 outward from the back surface 101b.

  Therefore, when the shaft member 102 is inserted into the through hole of the holding portion 115, the rectangular corner 112a located at the corner between the back surface 101b and the inner circumferential end surface 112b contacts the press-fit shaft 123, When the inner peripheral side end surface 112b of the curved portion 112 rubs against the press-fit shaft portion 123, there is a possibility that the corner portion 112a of the curved portion 112 may be chipped off. In addition, since the corner 125 of the shaft member 102 includes the overhang 125a, the corner 112a at the right angle of the curved portion 112 may be chipped by being pressed against the overhang 125a.

  Furthermore, even when the corner 112a of the curved portion 112 is not chipped, the corner 112a interferes with the overhanging portion 125a, so that the press-in is surely performed until the flange portion 124 abuts on the back surface 101b of the escape gear portion 101. It becomes difficult to insert the shaft portion 123. If the corner 112a of the curved portion 112 is chipped or if the press-fit shaft 123 can not be reliably inserted into the holder 115, the quality of the escape wheel 35 is lowered and the productivity is lowered.

  In this embodiment, since the corner 112a located at the corner between the back surface 101b and the inner end surface 112b is formed in an arc shape, the inner end surface 112b of the curved portion 112 is located on the outer periphery from the back surface 101b. When inserting the shaft member 102 so as to spread out, chipping does not easily occur even if the press-fit shaft portion 123 contacts the corner portion 112 a. Further, since the arc-shaped corner portion 112a of the curved portion 112 is formed at a position facing the corner portion 125 of the press-fit shaft portion 123 and the flange portion 124, interference between the corner portion 112a and the overhang portion 125a is alleviated. Be done. As a result, the occurrence of chipping of the corner portion 112 a of the curved portion 112 can be suppressed, and the press-fit shaft portion 123 can be inserted into the holding portion 115 easily and reliably.

  When the shape of the overhanging portion 125a at the corner portion 125 of the shaft member 102 is approximated to a circular arc of radius R1 and the shape of the corner portion 112a of the curved portion 112 is approximated to a circular arc of radius R2, R1 <R2 is preferable . With such a configuration, when the press-fit shaft portion 123 is inserted into the holding portion 115, the corner portion 112a of the curved portion 112 and the overhang portion 125a do not interfere with each other. The holding portion 115 can be inserted.

  In the present embodiment, although the projecting portion 125 a is provided at the corner portion 125, ideally, the projecting portion 125 a is not provided at the corner portion 125 of the shaft member 102, that is, the shaft member It is desirable that the corner 125 of 102 be square.

  FIG. 9 shows a state in which the outer peripheral side end surface 114b of the tooth portion 114 of the escape gear portion 101 is in contact with the end surface 144c of the claw stone 144b of the ankle 36. The cross-sectional shape of the corner portion 114 a between the back surface 101 b of the tooth portion 114 and the outer peripheral side end surface 114 b is an arc shape.

  Here, also in the case of the tooth portion 114, it is assumed that the corner portion 114a does not have an arc shape but a right angle. In this case, the outer end surface 114b of the tooth portion 114 contacts the end surface 144c of the toe stone 144b over the entire length in the thickness direction (axial direction), or the outer end surface 114b of the tooth portion 114 and the end surface of the toe stone 144b When the tooth portion 114 and the toe stone 144b are stretched when the 144c contacts with each other in a non-parallel state, the frictional force between the toe stone 144b of the ankle 36 meshing with the tooth portion 114 of the offset gear portion 101 There is a risk of becoming large. When the frictional force is increased, the resistance to the rotation of the escape gear portion 101 is increased, and the energy transfer efficiency is reduced. Therefore, the accuracy of the mechanical timepiece 1 is reduced.

  In this embodiment, since the cross-sectional shape of the corner portion 114a of the tooth portion 114 is arc-shaped, the range in which the outer peripheral side end surface 114b of the tooth portion 114 contacts the end surface 144c of the nail 144b can be reduced. In addition, even when the outer peripheral side end surface 114b of the tooth portion 114 and the end surface 144c of the toe stone 144b contact in a non-parallel state, the tooth portion 114 and the toe stone 144b are less likely to be stretched. Therefore, it is possible to reduce the frictional force between the tooth portion 114 of the center gear portion 101 and the toe stone 144b of the pallet 36. Thereby, the resistance to the rotation of the escape gear portion 101 can be reduced, and the energy transfer efficiency is improved, so that the accuracy of the mechanical timepiece 1 can be improved.

[Manufacturing method of an escape wheel]
Next, a method of manufacturing the escape wheel 35 as a mechanical component according to the present embodiment will be described. FIG. 10 is a flowchart showing the method of manufacturing the escape wheel according to the present embodiment. 11 to 18 are schematic cross-sectional views showing a method of manufacturing an escape wheel. 11 to 18 correspond to the partial cross-sectional view shown in FIG. FIG. 19 is a schematic view showing an example of a schematic configuration of the anisotropic etching apparatus. FIG. 20 is a schematic view showing an example of a schematic configuration of an isotropic etching apparatus.

  As shown in FIG. 10, in the method of manufacturing the escape wheel 35 as a mechanical component according to the present embodiment, a step (step S01 to step S07) of forming a gear portion (an adjustable gear portion 101) as a rotating member. And the step of forming the shaft member 102 (step S11, step S12), and the step of assembling the escape gear portion 101 and the shaft member 102 prepared through these steps (step S21, step S22) . The step of forming the center gear portion 101 includes the step of anisotropic etching (step S05) and the step of isotropic etching (step S07).

  In the step of forming the center gear portion 101, first, the substrate 200 is prepared (step S01). As shown in FIG. 11, the substrate 200 is a wafer-like substrate containing silicon, and is a mother substrate on which a plurality of center gear portions 101 can be taken. One surface of the substrate 200 is referred to as a front surface 200a, and the other surface is referred to as a back surface 200b. The thickness of the substrate 200 is T0. For example, when the thickness T1 (see FIG. 7) when the on-gear portion 101 is completed is 120 μm, the thickness T0 of the substrate 200 is set to about 135 μm.

  Next, as shown in FIG. 11, a photoresist 211 is applied to the surface 200a of the substrate 200 by, eg, spin coating or spray coating (Step S02 shown in FIG. 10). As the photoresist 211, any of negative and positive materials can be employed. The photoresist 211 applied to the substrate 200 is cured at a predetermined temperature.

  Next, as shown in FIG. 12, the photoresist 211 is exposed by photolithography (step S03 shown in FIG. 10). Then, development is performed (step S04 shown in FIG. 10). In steps S03 and S04, a photoresist pattern 212 to be a mask (etching mask) corresponding to the plan view shape of the escape gear portion 101 is formed from the photoresist 211. The photoresist pattern 212 has an opening 21 a and corresponds to each of the plurality of bevel gears 101 obtained from the substrate 200.

  Next, as shown in FIG. 13, the substrate 200 is anisotropically etched using the photoresist pattern 212 along the shape of the lash gear portion 101 as a mask (step S05 shown in FIG. 10). For example, deep reactive ion etching (DRIE) using inductively coupled plasma (ICP) can be used as anisotropic etching in step S05.

  FIG. 19 shows a schematic configuration of an anisotropic etching apparatus 300 for performing DRIE by ICP. As shown in FIG. 19, the anisotropic etching apparatus 300 includes a stage 301 and a coil 302. The substrate 200 is mounted on the stage 301 such that the surface 200 a (see FIG. 12) on which the photoresist pattern 212 is formed faces the coil 302. The plasma P is generated by flowing a high frequency high current through the coil 302. Then, particles of plasma P are drawn from the opening 212 a of the photoresist pattern 212 to the surface 200 a of the substrate 200 by applying a bias to the stage 301. Thereby, the substrate 200 is etched substantially perpendicularly to the thickness direction along the photoresist pattern 212 from the surface 200 a side. The substrate 200 is cooled from the back surface 200 b side, for example, by helium.

  As shown in FIG. 13, in the anisotropic etching step (step S 05), a part in the thickness direction of the substrate 200 is left along the planar view shape of the on-gear portion 101 via the photoresist pattern 212. Etch. More specifically, the substrate 200 is deeply etched in a substantially vertical direction from the surface 200 a side to the depth T 2, and etched so as to leave a portion of thickness T 3 which is a part of the substrate 200 in the thickness direction on the back surface 200 b side. Do.

  In the present embodiment, the depth T2 of deep digging the substrate 200 from the surface 200a side is 130 μm, and the thickness T3 of the portion left on the back surface 200b side is 5 μm. Thus, holding portions 115 (curved portions 112), elastic portions 113, rim portions 111, and the like corresponding to the plurality of bevel gear portions 101 over the thickness (depth) of 130 μm from the surface 200a side of the substrate 200. And, the shape of the tooth portion 114 is formed. Then, the portion of thickness T3 on the back surface 200b side of the substrate 200 remains without being etched.

  In addition, if it etches until it penetrates the board | substrate 200 (Thickness T3 will be set to 0 micrometer), the several spur gear part 101 will be isolate | separated and separated from the board | substrate 200 which is a mother board | substrate. In addition, when etching is performed until the substrate 200 is penetrated, helium leaks to the surface 200 a side, and vertical processing can not be performed along the thickness direction. As in the present embodiment, by leaving a part on the back surface 200 b side of the substrate 200 without etching, the portion to be excavated can be processed substantially vertically along the thickness direction, and a plurality of The gear portion 101 can be held without being separated from the substrate 200.

  Next, as shown in FIG. 14, a removal process of removing the photoresist pattern 212 (photoresist 211) is performed (Step S06 shown in FIG. 10). FIG. 14 shows the state after the photoresist pattern 212 has been removed. The removal step (step S06) can be performed by wet etching with fuming nitric acid, an organic solvent or the like capable of dissolving and peeling off the photoresist pattern 212 (photoresist 211), oxygen plasma ashing or the like.

  Next, isotropic etching is performed on the entire surface of the back surface 200b of the substrate 200 in which the shape of the center gear portion 101 is formed (Step S07 shown in FIG. 10). As the isotropic etching in step S07, for example, reactive ion etching (RIE) by parallel plate can be used.

  FIG. 20 shows a schematic configuration of an isotropic etching apparatus 310 for performing RIE using a parallel plate. As shown in FIG. 20, the isotropic etching apparatus 310 includes a stage (lower electrode) 311 and an upper electrode 312 which are parallel flat plates. The substrate 200 is placed on the stage 311 (lower electrode). At this time, as shown in FIG. 15, the surface 200a and the back surface 200b of the substrate 200 are inverted, and the substrate 200 is mounted such that the surface 200a is on the stage 311 side and the back surface 200b is on the upper electrode 312 side.

  As shown in FIG. 20, the stage (lower electrode) 311 is grounded, and plasma P is generated between the stage 311 (lower electrode) and the upper electrode 312 by applying a high frequency voltage to the upper electrode 312. . The particles of plasma P are drawn to the entire surface of the back surface 200 b of the substrate 200 by the self bias of the stage 311 (lower electrode). Thereby, the substrate 200 is isotropically etched over the entire surface from the back surface 200 b side.

  FIG. 16 shows a state in which the portion of thickness T3 (5 μm) left on the back surface 200b side of the substrate 200 is removed in the isotropic etching step (step S07). At this time, the thickness of the substrate 200 is the shape of the holding portion 115 (curved portion 112), the elastic portion 113, the rim portion 111, and the tooth portion 114 of the on-off gear portion 101 in the anisotropic etching process (step S05). And the thickness T2 (130 μm) of the portion where the

  By removing the portion of thickness T3 from the back surface 200b side of the substrate 200, the plurality of center gear portions 101 are separated from the substrate 200 and separated into pieces. Therefore, the isotropic etching process is a process of separating the center gear portion 101. The surface of the substrate 200 (gage gear portion 101) in the state shown in FIG. 16 is denoted by 200c. By separating the escape gear portion 101, the curved portion 112, the rim portion 111, and the tooth portion 114 are formed with a substantially square corner 112a, a corner 111a, and a corner 114a, respectively.

  In the isotropic etching step (step S07), the etching is performed for a time longer than the time for removing the portion of the thickness T3 left on the back surface 200b side of the substrate 200. That is, the substrate 200 in the state shown in FIG. 16 is further etched continuously from the surface 200 c side. Then, as shown in FIG. 17, when the substrate 200 is etched by 10 μm from the surface 200 c side and the thickness of the substrate 200 becomes a predetermined thickness T 1 (120 μm) of the offset gear portion 101, isotropic etching The process (step S07) is ended. The surface of the substrate 200 in the state shown in FIG. 17 is 200d.

  Here, when the substrate 200 is etched from the state shown in FIG. 16 to the state shown in FIG. 17, the corner 112a of the curved portion 112 located on the surface 200c side, the corner 111a of the rim 111, and the teeth 114 The corner portion 114 a is etched from the side of the surface 200 c in the thickness direction of the substrate 200 and also etched from the direction intersecting the thickness direction of the substrate 200. As a result, on the surface 200 d side, the cross-sectional shapes of the corner 112 a of the curved portion 112, the corner 111 a of the rim 111, and the corner 114 a of the tooth 114 become arcs.

  In the anisotropic etching step (step S05), when the substrate 200 is dug using the so-called Bosch process, the etched portion (for example, the inner peripheral end surface 112b of the curved portion 112 or the outer peripheral side of the tooth portion 114) A scallop (step-like shape) is often formed on the end face 114b). In the present embodiment, in the isotropic etching step (step S07), the substrate 200 is further isotropically etched from the state in which the spur gear portion 101 is separated, so that the inner circumferential end face 112b of the curved portion 112 or Since the outer peripheral side end surface 114b of the tooth portion 114 is also slightly etched, the scallop can be relaxed.

  In the state shown in FIG. 17, the surface 200 d of the substrate 200 is the back surface 101 b of the offset gear portion 101, and the surface 200 a is the surface 101 a of the offset gear portion 101. Therefore, the corner 112a where the back surface 101b of the offset gear portion 101 and the inner peripheral side end surface 112b of the curved portion 112 intersect, the back surface 101b of the offset gear portion 101 and the outer peripheral end surface 114b of the tooth portion 114 The intersecting corner portions 114 a have an arc shape. By the above-described steps, a bevel gear portion 101 shown in FIG. 18 is completed.

  The process (step S11, step S12) of forming the shaft member 102 shown in FIG. 10 is performed separately from the process of forming the bevel gear portion 101 of step S01 to step S07.

  First, a member to be the shaft member 102 is prepared (step S11). The shaft member 102 desirably has sufficient rigidity as a shaft and has heat resistance to endure high temperature in the step of performing oxidation treatment described later. The material of the shaft member 102 is preferably tantalum (Ta) or tungsten (W), which is a material having sufficient heat resistance to the temperature of oxidation treatment such as thermal oxidation treatment performed at a high temperature of 1000 ° C. or more. Tantalum and tungsten are particularly preferable as the material of the shaft member 102 because they are materials having high workability such as cutting and grinding in addition to the above-described materials having excellent rigidity and heat resistance.

  Next, the shaft member 102 is formed by performing machining such as cutting and grinding on the member to be the shaft member 102 (step S12). Thereby, the shaft member 102 shown in FIG. 3 and FIG. 4 is completed.

  In addition, when performing machining such as cutting and grinding in step S12, an arc-like overhang protruding toward the corner 125 on the corner 125 between the press-fit shaft 123 and the flange 124 of the shaft member 102. The portion 125a may be formed (see FIG. 8). In this embodiment, even when the overhanging portion 125a is formed at the corner portion 125 of the shaft member 102, the corner portion 112a of the curved portion 112 facing the overhanging portion 125a is formed in an arc shape, which will be described later. In the shaft member positioning step (step S21), the interference between the corner 112a and the overhang 125a is alleviated.

  Next, the escape wheel 35 formed in the above-described step is combined with the shaft member 102 to form the escape wheel 35. In step S21 shown in FIG. 10, positioning is performed by inserting the shaft member 102 prepared in the above-described preparation process into the through hole in which the plurality of curved portions 112 of the holding portion 115 of the lash gear portion 101 overhangs. As described above, in step S21, when the shaft member 102 is inserted into the through hole in which the plurality of curved portions 112 of the holding portion 115 overhangs, the plurality of curved portions 112 in contact with the shaft member 102 in the holding portion 115 Stress is applied to push it outward.

  The escape gear portion 101 has the elastic portion 113 extending from between the adjacent curved portions 112 to the rim portion 111 between the plurality of curved portions 112 of the holding portion 115 and the rim portion 111. The stress applied to the curved portion 112 is relieved by the elasticity of the elastic portion 113, and the elasticity of the elastic portion 113 provides a holding force for holding the shaft member 102. Therefore, when the shaft member 102 is inserted into the holding portion 115, the stress applied to the bending portion 112 suppresses the damage such as breakage of the escape gear portion 101, and the appropriate holding force for the escape gear portion 101. The shaft member 102 can be held and positioned.

  In the present embodiment, as shown in FIG. 8, since the corner 112 a located at the corner between the back surface 101 b and the inner end face 112 b is formed in an arc, in step S 21 the curved portion 112 from the back surface 101 b side. When the shaft member 102 is inserted so as to spread the inner peripheral side end surface 112b to the outer peripheral side, chipping does not easily occur even if the press-fit shaft portion 123 contacts the corner portion 112a. Further, since the arc-shaped corner portion 112a of the curved portion 112 is formed at a position facing the corner portion 125 of the press-fit shaft portion 123 and the flange portion 124, interference between the corner portion 112a and the overhang portion 125a is alleviated. Be done. As a result, in step S21, the occurrence of chipping of the corner portion 112a of the curved portion 112 can be suppressed, and the press-fit shaft portion 123 can be inserted into the holding portion 115 easily and reliably.

Subsequently, in step S22 shown in FIG. 10, oxidation treatment is performed to form a silicon oxide film made of silicon dioxide (SiO ₂ ) on the surface of the lash gear portion 101 positioned by inserting the shaft member 102 into the holding portion 115. I do. The oxidation treatment is preferably performed by thermal oxidation treatment performed at a high temperature of, for example, 1000 ° C. or more. According to the thermal oxidation process, a dense silicon oxide film having a predetermined thickness can be formed in a relatively short time. In the present embodiment, a thermal oxidation process is performed by a steam oxidation method. In the steam oxidation method, since the growth of the silicon oxide film is quicker than the dry oxidation method in the thermal oxidation treatment, a silicon oxide film having a desired thickness can be formed more efficiently.

  In step S22, the silicon oxide film formed on the surface (the surface including the inner peripheral end surface 112b of the curved portion 112 and the surface 101a and the back surface 101b) of the escape gear portion 101 made of a material containing silicon The mechanical strength of the gear portion 101 is improved. And, by the action described below, it is possible to improve the fitting strength between the escape gear portion 101 as the rotation member and the shaft member 102 in the escape wheel 35 as the mechanical component.

  That is, the silicon oxide film formed on the surface of the offset gear portion 101 is retained by performing the oxidation process after the shaft member 102 is inserted and positioned in the holding portion 115 of the offset gear portion 101. Around the contact portion between the curved portion 112 of the portion 115 and the shaft member 102, the gap between the curved portion 112 and the shaft member 102 is formed so as to be filled. As a result, the escape wheel 35 can be provided as a mechanical component in which the press-fit shaft portion 123 of the shaft member 102 is fitted to the holding portion 115 and the shaft member 102 is firmly fixed to the release gear portion 101. .

  In addition, since the shaft member 102 formed by machining such as cutting and grinding has irregularities such as minute scratches on the surface, the silicon oxide film of the escape gear portion 101 is used for these irregularities. By soaking, a so-called anchor effect works to obtain an effect that the shaft member 102 is more firmly fixed to the holding portion 115 of the escape gear portion 101.

  A series of manufacturing processes of the escape wheel 35 as a machine part are completed by passing through the process to the oxidation treatment process described above. In addition, according to the manufacturing method of the mechanical component of this embodiment, since the mechanical component (the on-gear portion 101) is formed using the silicon substrate, the mechanical component is manufactured using the SOI substrate described in Patent Document 1. Compared with the forming method, it is possible to reduce the production cost of machine parts.

  The above embodiment merely shows one aspect of the present invention, and any modification and application can be made within the scope of the present invention. As a modification, for example, the following can be considered.

(Modification 1)
Although the above-mentioned embodiment explained that tantalum or tungsten was preferred as a material of shaft member 102, the present invention is not limited to this. A material containing silicon may be used as the material of the shaft member 102.

  According to such a configuration, the shaft member 102 is inserted into and held in the holding portion 115 of the offset gear portion 101 and positioned after the oxidation process, only by the surface of the offset gear portion 101 which is a rotating member. Instead, a silicon oxide film is also formed on the surface of the shaft member 102. Therefore, the shaft member 102 can be firmly fixed to the holding portion 115 of the bevel gear portion 101 as the rotation member in a shorter time and more strongly.

(Modification 2)
Although the above-mentioned embodiment explained that tantalum or tungsten was preferred as a material of shaft member 102, it does not restrict to this. As a material of the shaft member 102, a material including carbon steel may be used. Alternatively, a silicon oxide film may be formed in advance on the surface of the escape gear portion 101, and the shaft member 102 may be inserted thereafter. Furthermore, even when the silicon oxide film is not formed on the surface of the escape gear portion 101 or when the escape gear portion 101 is formed of metal or the like, the above-mentioned elastic portion makes the shaft member regardless of the presence or absence of the oxide film. It is possible to hold 102 with a suitable holding force.

(Modification 3)
The configuration and the plan view shape of the offset gear portion 101 as a rotating member according to the present invention are not limited to the shape shown in FIG. 5 of the above embodiment. The configuration (for example, the portions of the rim portion 111, the holding portion 115, the elastic portion 113, etc.) of the bevel gear portion 101 may be different, and the shape in plan view may be another shape.

(Modification 4)
In the above embodiment, as a method of manufacturing the mechanical component (the escape wheel 35), after the step of inserting and positioning the shaft member 102 in the holding portion 115 of the escape gear portion 101 as the rotating member, Although the structure which performs the oxidation process which forms a silicon oxide film in the surface of the tooth gear part 101 was demonstrated, this invention is not limited to this. The mechanical strength of the escape gear portion 101 in a state in which oxidation processing is not performed is sufficiently and sufficiently secured, and in the positioning step, the shaft member 102 held by the holding portion 115 of the offset gear portion 101 is held. If a sufficient amount of force can be secured, it may be configured not to perform the oxidation treatment.

(Modification 5)
In the said embodiment, although the escape wheel 35 was mentioned as an example and demonstrated as an example of a machine component, this invention is not limited to this. The configuration of the machine parts of the present invention and the method of manufacturing the same are also applicable to other machine parts such as the barrel car 22, the second wheel 25, the third wheel 26, the fourth wheel 27, the ankle 36, the balance 40 and the like. .

  DESCRIPTION OF SYMBOLS 1 ... mechanical watch (clock), 35 ... escape wheel (machine parts), 101 ... escape gear part (rotation member), 101a ... surface (one side), 101b ... surface (the other side), 102: shaft member, 111: rim portion, 112: curved portion (holding portion), 112a: corner portion, 114: tooth portion, 114a: corner portion, 115: holding portion, 125a: overhang portion, 200: substrate, 200a ... front surface (one surface), 200b ... back surface (other surface).

Claims (7)

Shaft member,
A rotating member having a holding portion for holding the shaft member, and a rim portion having a plurality of tooth portions,
A cross-sectional shape of the corner portion of the holding portion and the corner portion of the tooth portion are both formed in an arc shape.   The corner portion formed in an arc shape is formed at a corner portion where one surface of the rotating member intersects the end surface of the holding portion and the end surface of the tooth portion. Machine parts described.   The machine component according to claim 1 or 2, wherein the arc-shaped corner of the holding portion and the arc-shaped corner of the tooth portion have the same shape.   The mechanical component according to any one of claims 1 to 3, wherein the shaft member has an overhanging portion in a region where it engages with the arc-shaped corner portion of the holding portion.   A timepiece comprising the mechanical component according to any one of claims 1 to 4. Anisotropically etching one side of the substrate along the shape of the mechanical component leaving a part in the thickness direction of the substrate;
And d) separating the mechanical component by isotropically etching the other surface of the substrate.   The method of manufacturing a mechanical part according to claim 6, wherein, in the step of separating the mechanical part, the isotropic etching is performed for a time longer than a time for removing a part in the thickness direction of the substrate. .

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