Regulating mechanism, mechanical watch

Abstract

To provide a mechanical watch 1 capable of maintaining rotation even if the torque by a spring force of a hairspring 32 is reduced.SOLUTION: A mechanical watch 1 includes a power spring 11, a balance wheel 31, a hairspring 32, a permanent magnet 41, a coil 43, a soft magnetic core 42, and speed adjustment means 40. The permanent magnet 41 is arranged so that, when the hairspring 32 is positioned of 0° in its neutral position of elastic deformation, a south pole portion 412 faces a first end portion 421a with a first gap, and an N pole portion 411 faces a second end portion 422a with a second gap, and when the hairspring 32 is a 180°position, the south pole portion 412 faces the second end portion 422a with a third gap, and the N-pole portion 411 faces the first end portion 421a with a fourth gap, in which the second gap is smaller than the first gap, and the difference between the fourth gap and the third gap is smaller than the difference between the first gap and the second gap.SELECTED DRAWING: Figure 7A

Description

[Technical field]

[0001] The present invention relates to a mechanical timepiece. [Background technology]

[0002] In conventional mechanical watches, one second is generated based on the reciprocating motion of a balance wheel including a balance spring, and as the number of reciprocating motions per second increases, the error per second, i.e., the impact on rate accuracy, decreases. For example, Patent Document 1 discloses a technique for improving rate accuracy by reducing the inertia of the escapement and causing the balance to vibrate at a high speed. Patent Documents 2 and 3 disclose techniques for adjusting the rate in mechanical watches equipped with a balance wheel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-185932 A [Patent Document 2] JP 2019-113548 A [Patent Document 3] JP 2020-38206 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, if the torque generated by the spring force of the hairspring is increased to increase the frequency of the balance, the mechanisms that transmit power are more susceptible to wear and durability is reduced.On the other hand, if the torque generated by the spring force of the hairspring is reduced to decrease the frequency of the balance, the torque generated by the spring force of the hairspring cannot counter the frictional force generated between the pallet and the escape wheel, and rotation may stop.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a mechanical timepiece that maintains rotation even when the torque caused by the spring force of the hairspring is reduced. [Means for solving the problem]

[0006] (1) A speed-regulating mechanism including a power source, a balance wheel driven by power from the power source, and a hairspring that elastically deforms to rotate the balance wheel in forward and reverse directions, a permanent magnet that rotates in forward and reverse directions in association with the forward and reverse rotation of the balance wheel, the permanent magnet including a first polarity portion and a second polarity portion having a polarity different from that of the first polarity portion, a coil, a soft magnetic core including a first end portion provided so that magnetic resistance is generated between the permanent magnet and the coil, and a second end portion provided on the opposite side of the first end portion via the permanent magnet so that magnetic resistance is generated between the permanent magnet and the coil, and a detection voltage generated in the coil by the movement of the permanent magnet associated with the forward and reverse movements of the balance wheel, and a reference frequency of a reference signal source. and a rate adjusting means for adjusting the rate based on the rate, wherein the permanent magnet is arranged such that, at a first angular position when the hairspring is in a neutral position of its elastic deformation, the first polarity portion faces the first end with a first interval and the second polarity portion faces the second end with a second interval, and at a second angular position rotated 180° from the first angular position, the first polarity portion faces the second end with a third interval and the second polarity portion faces the first end with a fourth interval, the second interval being smaller than the first interval and a difference between the fourth interval and the third interval being smaller than a difference between the first interval and the second interval.

[0007] (2) In the mechanical watch according to (1), the planar shape of the permanent magnet is circular, and the center position of the permanent magnet is disposed at a position different from the center of rotation of the balance shaft, which is the axis of rotation of the balance wheel.

[0008] (3) A mechanical watch according to (2), wherein the inner circumferential surface of the first end portion and the inner circumferential surface of the second end portion of the soft magnetic core form an opening having a circular planar shape, and the center position of the opening of the soft magnetic core is located at a position different from the center of rotation.

[0009] (4) A mechanical watch according to (3), wherein, when the permanent magnet is in the first angular position, the center position of the permanent magnet and the center position of the opening of the soft magnetic core are in symmetrical positions relative to the center of rotation.

[0010] (5) A mechanical timepiece according to (4), wherein when the permanent magnet is in the second angular position, the center position of the permanent magnet coincides with the center position of the opening of the soft magnetic core.

[0011] (6) A mechanical timepiece according to any one of (3) to (5), wherein, when the permanent magnet is in the first angular position, the center position of the permanent magnet, the center of rotation of the rotating shaft, and the center position of the opening of the soft magnetic core are aligned on a straight line perpendicular to the boundary between the first polarity portion and the second polarity portion.

[0012] (7) A mechanical timepiece according to any one of (3) to (6), comprising: a support member which supports the soft magnetic core and is fixed to a main plate; and a positioning frame which is attached to the support member and positions the soft magnetic core, the positioning frame being arranged so that its center position coincides with the center of rotation of a balance shaft which is the axis of rotation of the balance wheel, and having an annular positioning protrusion which fits into an opening of the soft magnetic core, and the center position of the positioning protrusion being located at a position different from the center position of the positioning frame.

[0013] (8) A mechanical timepiece according to any one of (1) to (7), which has a retaining member for holding the permanent magnet, the retaining member having an insertion hole through which a balance stem which is the rotation axis of the balance wheel is inserted, the balance stem rotates integrally with the balance stem when the balance stem is inserted through the insertion hole, and the center position of the insertion hole is located at a position different from the center position of the retaining member.

[0014] (9) A mechanical watch according to any one of (1) to (8), wherein when the coil is in a non-energized state and the permanent magnet is between the first angular position and the second angular position, a magnetic attraction force acts between the permanent magnet and the soft magnetic core in a direction that rotates the permanent magnet toward the first angular position.

[0015] (10) A mechanical timepiece according to any one of (1) to (9), comprising a jewel which abuts against one end of a balance shaft which is the axis of rotation of the balance wheel, thereby positioning the balance shaft in the axial direction, and a jewel holding member which is annular and surrounds at least a portion of the outer circumferential surface of the permanent magnet and holds the jewel, the jewel holding member being made of a magnetic material and having a notch formed in at least a portion of the portion facing the outer circumferential surface of the permanent magnet.

[0016] (11) A mechanical timepiece according to any one of (1) to (10), wherein the forward and reverse rotational motion of a balance shaft, which is the rotation axis of the balance wheel, includes at least a period in which the balance shaft rotates freely relative to the hairspring, and a period in which a rotational force is transmitted to the hairspring and the hairspring is elastically deformed.

[0017] (12) The mechanical watch according to (11), wherein the hairspring is not fixed relative to the balance shaft.

[0018] (13) A mechanical watch according to (11) or (12), further comprising a contact portion that repeatedly comes into and out of contact with the hairspring in accordance with the forward and reverse rotational motion of the balance spring.

[0019] (14) A mechanical timepiece according to (13), wherein the hairspring includes an elastically deformable spiral spring portion, an inner end portion through which the balance stem is inserted, and a connecting portion that connects the spring portion and the inner end portion and forms a gap between the spring portion and the inner end portion to allow movement of the contact portion.

[0020] (15) A mechanical timepiece according to (14), including a period during which the contact portion is not in contact with the connection portion at least while the rotation angle of the balance is greater than or equal to 0° and less than 180°.

[0021] (16) A mechanical watch according to (14) or (15), further comprising a holding member which holds the permanent magnet and rotates integrally with the balance shaft, the contact portion being provided on the holding member.

[0022] (17) A mechanical watch as described in (14) or (15) above, further comprising a retaining member which holds the permanent magnet and rotates integrally with the balance shaft, and the contact portion is provided on a member which is separate from the retaining member and which rotates integrally with the balance shaft.

[0023] (18) A mechanical timepiece according to any one of (14) to (17), wherein the planar shape of the connection portion includes a portion that expands radially outward, and the period during which the balance shaft rotates freely relative to the hairspring is determined according to the degree of expansion of the portion that expands radially outward.

[0024] (19) The mechanical timepiece according to any one of (14) to (18), wherein the planar shape of the connection portion includes a portion whose distance from the center of rotation of the hairspring is shorter than the radius of the rotation locus of the outermost portion of the connection portion.

[0025] (20) A mechanical watch according to any one of (8), (16) and (17), wherein the holding member has a center of gravity adjustment portion that adjusts the center of gravity of a rotating body consisting of the permanent magnet and the holding member. Effect of the Invention

[0026] According to the above aspects (1) to (20) of the present invention, it is possible to provide a mechanical timepiece that maintains rotation even when the spring constant of the hairspring is reduced. [Brief description of the drawings]

[0027] [Figure 1]FIG. 2 is a perspective view showing the base plate and each member assembled thereto in the first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a mechanism for transmitting power and its surroundings in the first embodiment. [Diagram 3] FIG. 2 is a plan view showing the pallet fork, the escape wheel and the surrounding members in the first embodiment. [Figure 4] 3A and 3B are diagrams illustrating the rotation range and direction of a balance wheel in the first embodiment. [Diagram 5] 1 is a block diagram showing the overall configuration of a mechanical timepiece according to a first embodiment. [Figure 6] 5A to 5C are diagrams illustrating the relationship between the operation of a balance wheel and the back electromotive voltage generated in a coil in the first embodiment. [Figure 7A] FIG. 2 is a plan view showing the arrangement of a permanent magnet, a soft magnetic core, and a temperature stud in the first embodiment. [Figure 7B] FIG. 2 is a plan view showing the arrangement of a permanent magnet, a soft magnetic core, and a temperature stud in the first embodiment. [Figure 8] 3A to 3C are diagrams illustrating torques acting on a permanent magnet in the first embodiment. [Figure 9] FIG. 11 is a plan view showing the arrangement of a permanent magnet, a soft magnetic core, and a balance rod in a comparative example. [Figure 10] 7A to 7C are diagrams illustrating torques acting on a permanent magnet in a comparative example. [Figure 11] FIG. 2 is a perspective view showing each member that rotates together with the balance shaft in the first embodiment. [Figure 12] 12 is an exploded perspective view showing the members shown in FIG. 11 in an exploded state. [Figure 13] FIG. 2 is a perspective view showing a bottom portion of the holding member of the first embodiment. [Figure 14A] FIG. 2 is a perspective view showing a holding member of the first embodiment. [Figure 14B] FIG. 2 is a plan view showing the holding member of the first embodiment. [Figure 15] FIG. 2 is an exploded perspective view showing the balance shaft and the swing seat. [Figure 16]FIG. 2 is a perspective view showing a soft magnetic core and its peripheral members in the first embodiment. [Figure 17] 17 is an exploded perspective view showing the soft magnetic core shown in FIG. 16 disassembled from the support member. [Figure 18A] FIG. 2 is a perspective view showing a positioning frame according to the first embodiment. [Figure 18B] FIG. 2 is a plan view showing the positioning frame of the first embodiment. [Figure 18C] FIG. 2 is a perspective view showing a positioning frame according to the first embodiment. [Figure 19] FIG. 2 is a perspective view showing a bearing structure and its peripheral members in the first embodiment. [Figure 20] FIG. 2 is an oblique view showing the stone holding member of the first embodiment. [Figure 21] 1 is a plan view showing the stone holding member of the first embodiment and its surrounding members. FIG. [Figure 22] FIG. 4 is a plan view showing an arrangement of a permanent magnet, a soft magnetic core, and a temperature stud in a first modified example of the first embodiment. [Diagram 23] FIG. 11 is a plan view showing an arrangement of a permanent magnet, a soft magnetic core, and a temperature stud in a second modified example of the first embodiment. [Figure 24] FIG. 13 is a plan view showing an arrangement of a permanent magnet, a soft magnetic core, and a temperature stud in a third modified example of the first embodiment. [Diagram 25] 10A to 10C are diagrams illustrating torques acting on a permanent magnet in the second embodiment. [Figure 26] FIG. 11 is an exploded perspective view showing a balance wheel, a balance arbour, a permanent magnet, a hairspring, and peripheral members thereof in a second embodiment. [Figure 27] FIG. 11 is a perspective view showing a holding member in the second embodiment. [Figure 28] FIG. 11 is a cross-sectional view showing a balance wheel, a balance arbour, a permanent magnet, a hairspring, and a retaining member in a second embodiment. [Figure 29A] This indicates that the balance wheel rotation angle is 0°. [Figure 29B] This indicates that the balance wheel has rotated 135°. [Figure 29C]This indicates that the balance wheel has rotated 315°. [Figure 29D] This indicates that the balance wheel is at a rotation angle of -135°. [Figure 29E] This indicates that the balance wheel is at -315° rotation angle. [Figure 30A] FIG. 11 is a perspective view showing a protrusion in a modified example of the second embodiment. [Figure 30B] FIG. 11 is a cross-sectional view showing a case where a protrusion portion is used in a modified example of the second embodiment. [Diagram 31] FIG. 13 is a perspective view showing a modified example of the holding member. [Diagram 32] FIG. 13 is a perspective view showing a modified example of the permanent magnet. [Diagram 33] 11A and 11B are diagrams illustrating modified examples regarding the arrangement angles of the permanent magnets and the soft magnetic cores. [Diagram 34] FIG. 13 is a plan view showing a modified example of the hairspring. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings.

[0029] [Overall configuration overview] First, referring to Figs. 1 to 6, an overview of the overall configuration of the mechanical timepiece 1 according to the first embodiment will be described. Fig. 1 is a perspective view showing the main plate of the first embodiment and each member incorporated therein. Fig. 2 is a perspective view showing the mechanism for transmitting power and its periphery in the first embodiment. Fig. 3 is a plan view showing the anchor, escape wheel, and its periphery in the first embodiment. Fig. 4 is a diagram explaining the rotation range and rotation direction of the balance wheel in the first embodiment. Fig. 5 is a block diagram showing the overall configuration of the mechanical timepiece according to the first embodiment. Fig. 6 is a diagram explaining the relationship between the operation of the balance wheel in the first embodiment and the back electromotive voltage generated in the coil. Note that Figs. 1 and 2 show the mechanical timepiece 1 as viewed from the back side, and Fig. 3 shows the mechanical timepiece 1 as viewed from the front side. The back side is the side of the mechanical timepiece 1 in the thickness direction where the back cover of the exterior case is arranged, and the front side is the side of the mechanical timepiece 1 in the thickness direction where the dial is arranged.

[0030] The mechanical timepiece 1 is a timepiece that uses a power spring 11 as a power source, and controls the movement of the power spring 11 by an escapement mechanism 20 and a speed regulator mechanism 30 while driving the hands. The mechanical timepiece 1 is configured by housing a main plate 10, into which the mechanisms that drive the hands are assembled, in an exterior case. Note that in the first embodiment, the exterior case is not shown. Also, the crown that is placed on the side of the exterior case is not shown. The crown is attached to the end of the winding stem 2 shown in FIG. 1.

[0031] [Overall configuration: Drive mechanism configuration] An overview of the drive mechanism of the mechanical timepiece 1 will be described. In the first embodiment, the mechanism including the power spring 11, which is the power source, the wheel train, and the hand shaft 13 is referred to as the "drive mechanism." Note that in Fig. 2, only the second hand 131 of the hands is shown. The drive mechanism shown in Fig. 2 is one example, and is not limited to this, and may include gears other than those shown in the figure.

[0032] The power spring 11 is made of a metal band-shaped body and is housed in a barrel 110 having a plurality of teeth formed on its outer circumference. The barrel 110 is disk-shaped and has a cavity formed therein for housing the power spring 11. The inner end of the power spring 11 is fixed to a barrel stem (not shown) which is a rotating shaft provided at the center of the barrel 110, and the outer end is fixed to the inner surface of the barrel 110. When the crown is rotated by a user's operation, the winding stem 2 rotates. The power spring 11 is wound up in accordance with the rotation of the winding stem 2. The wound power spring 11 is unwound by its elastic force. The operation of the power spring 11 at this time causes the barrel 110 to rotate.

[0033] The wheel train includes at least a center wheel 122, a third wheel 123, and a fourth wheel 124. The center wheel 122 includes a pinion that meshes with a plurality of teeth formed on the barrel 110 that functions as the first wheel, a rotating shaft, and a plurality of teeth, and transmits the rotation of the barrel 110 to the third wheel 123. The rotating shaft of the center wheel 122 is the pointer shaft of the minute hand (not shown). The third wheel 123 includes a pinion that meshes with a plurality of teeth of the center wheel 122, a rotating shaft, and a plurality of teeth, and transmits the rotation of the center wheel 122 to the fourth wheel 124. The fourth wheel 124 includes a pinion that meshes with a plurality of teeth of the third wheel 123, a rotating shaft, and a plurality of teeth, and transmits the rotation of the third wheel 123 to the escapement mechanism 20. As shown in FIG. 2, the rotating shaft of the fourth wheel 124 is the pointer shaft 13 of the second hand 131.

[0034] [Overview of the overall configuration: Overview of the configuration of the escapement mechanism 20 and the speed regulator mechanism 30, and their operation] Next, the escapement mechanism 20 and the regulating mechanism 30 will be described. Power from the power spring 11 is transmitted to the escapement mechanism 20 and the regulating mechanism 30 through a wheel train. The escapement mechanism 20 includes an escape wheel 21 and an anchor 22. The regulating mechanism 30 includes a balance wheel 31 and a hairspring 32. The regulating mechanism 30 is sometimes called a balance.

[0035] The balance wheel 31 rotates forward and backward around the balance arbour 311, which is its rotation axis, by the power transmitted by the wheel train. In the following description, the forward motion of the forward and reverse rotational motion is called "forward rotation" and the reverse motion is called "reverse rotation." In the first embodiment, the counterclockwise direction in each drawing such as FIG. 7A is described as the forward rotation, and the clockwise direction is described as the reverse rotation.

[0036] As shown in Fig. 3, the balance wheel 31 may have a circular outer shape. However, the shape of the balance wheel 31 shown in Fig. 3 is only an example, and the shape of the balance wheel 31 is arbitrary.

[0037] The hairspring 32 expands and contracts (elastically deforms) so as to rotate the balance wheel 31 in forward and reverse directions. The hairspring 32 is spiral-shaped, with its inner end fixed to the balance arbour 311 and its outer end fixed to a hairspring holder 34. The hairspring holder 34 is fixed to the main plate 10 together with the support member 33.

[0038] The escape wheel 21 is a component that receives the rhythm of the regulating mechanism 30 from the pallet fork 22 by meshing with the pallet fork 22 and converts it into regular rotational motion. The escape wheel 21 includes a pinion that meshes with multiple teeth of the second wheel & pinion 124, a rotating shaft, and multiple teeth. As shown in Figure 2, the multiple teeth of the escape wheel 21 are formed at wider intervals in the circumferential direction than the teeth of each gear of the train wheel.

[0039] The pallet fork 22 rotates forward and backward around the pallet fork 221 shown in Fig. 3 as a rotation axis. The pallet fork 22 extends from the pallet fork 221 toward the center of the balance wheel 31 (balance fork 311) and has a rod portion 222 that hits an impulse jewel 312a that rotates together with the balance fork 311. The tip of the rod portion 222 is formed in a U-shape and is sometimes called an pallet box. The impulse jewel 312a is fixed to an impulse seat 312 (see Figs. 11, 15, etc.) that rotates together with the balance fork 311.

[0040] The pallet fork 22 has a first arm 223 to which is attached a recessed prong 223a that hits multiple teeth of the escape wheel 21, and a second arm 224 to which is attached a projecting prong 224a that extends in the opposite direction to the first arm 223 and hits multiple teeth of the escape wheel 21. The recessed prong 223a and the projecting prong 224a may be made of a stone such as sapphire.

[0041] The operation of the speed regulating mechanism 30 will be described with reference to FIG. 3. The escape wheel 21 is constantly given a torque that rotates in the direction of the arrow shown in FIG. 3 with the rotation of the fourth wheel 124, and is stopped by the collision of the tooth of the escape wheel 21 with the set pawl 223a of the pallet fork 22. When the balance wheel 31 rotates, the impulse jewel 312a pushes the pallet box, causing the pallet fork 22 to rotate and releasing the stop between the pallet fork 22 and the escape wheel 21. When the stop release is completed, the tooth of the escape wheel 21 pushes up the set pawl 223a, causing the pallet fork 22 to rotate. Until now, the impulse jewel 312a has been pushing the pallet box, but conversely, the pallet box pushes the impulse jewel 312a, transmitting rotational energy to the balance wheel 31. When the tooth of the escape wheel 21 leaves the set pawl 223a, the escape wheel 21 spins freely, and the escape wheel 21 stops again at the position where the tooth of the escape wheel 21 hits the projecting pawl 224a. The balance wheel 31 rotates after receiving the rotational energy, and then rotates in the opposite direction due to the spring torque of the hairspring 32, and the same operation as above is performed on the protruding pawl 224a side. This realizes regular intermittent rotation of the escape wheel 21 and the train wheel. As described later, the balance wheel 31 is designed to perform one reciprocating motion in two seconds, so that the escape wheel 21 performs one step motion per second.

[0042] In the first embodiment, a resin material with a low Young's modulus is used as the material for the hairspring 32. This makes it possible to achieve slower vibration of the balance wheel 31 than when it is made of a metal material. If one were to try to achieve slower vibration with a metal hairspring, it would be necessary to reduce the cross-sectional area of ​​the hairspring 32 to a level that makes it difficult to process, or to increase the length of the hairspring to a level that makes it difficult to handle.

[0043] In the first embodiment, a resin having a Young's modulus of about 5 [GPa] was used as the material of the hairspring 32. Specifically, polyester was used as the material of the hairspring 32. The hairspring 32 made of a resin material may be manufactured by, for example, laser processing. The Young's modulus of a general metal hairspring is about 200 [GPa]. The Young's modulus shown here is an example, and the Young's modulus of the hairspring 32 may be 20 [GPa] or less. That is, the Young's modulus of the hairspring 32 may be 1 / 10 or less of the Young's modulus of the metal hairspring. More preferably, the Young's modulus of the hairspring 32 may be 10 [GPa] or less. That is, the Young's modulus of the hairspring 32 may be 1 / 20 or less of the Young's modulus of the metal hairspring. Also, the Young's modulus may be 20 [GPa] or less, and the hairspring 32 may be made of a material such as paper or wood.

[0044] In the first embodiment, the rotation angle [deg] of the balance wheel 31 and the permanent magnet 41 in a state where the hairspring 32 is in a neutral position of elastic deformation is set to 0°. The neutral position of elastic deformation of the hairspring 32 is, in other words, a position where the hairspring 32 is at its natural length. Power is supplied from the power spring 11 to the balance wheel 31 in a state where the hairspring 32 is in the vicinity of the neutral position of elastic deformation. In the first embodiment, the permanent magnet 41 is in a magnetically balanced position at a rotation angle of 0°, as described later.

[0045] In the first embodiment, as shown in Fig. 4, the balance wheel 31 is designed to drive within a rotation angle range of 340° to -340°, which is a range in which the balance wheel 31 does not reach the swing-stop position. The swing-stop position is a position in which the roller jewel 312a rotates too far and hits the rod portion 222 of the pallet fork 22. Since the balance wheel 31 rotates forward and backward within a range in which it does not pass the swing-stop position, the permanent magnet 41 also drives within a rotation angle range of 340° to -340°.

[0046] The solid line in Fig. 4 indicates the range in which the balance wheel 31 advances from the 0° position due to the power from the power spring 11, and the dotted line in Fig. 4 indicates the range in which the balance wheel 31 returns from the ±340° position due to the elastic force of the hairspring 32. Note that this is just one example, and it is preferable that the movement range of the balance wheel 31 is greater than or equal to the range of rotation angles from 270° to -270°. By increasing the movement range of the balance wheel 31 to a certain extent in this way, it is possible to achieve a slower vibration of the balance wheel 31.

[0047] As described above, the speed regulating mechanism 30 repeatedly rotates the balance wheel 31 in forward and reverse directions (reciprocating motion) at a constant cycle by the expansion and contraction motion of the hairspring 32. The escapement mechanism 20 continuously applies force to the balance wheel 31 for reciprocating motion, and rotates each gear in the wheel train at a constant speed by the regular vibration from the balance wheel 31.

[0048] [Overall Configuration: Configuration of the Rate Adjustment Means 40] Next, a description will be given of the configuration of the rate adjustment means 40. The mechanical timepiece 1 according to the first embodiment includes the rate adjustment means 40 in addition to the drive mechanism, the escapement mechanism 20, and the speed regulation mechanism 30.

[0049] The rate adjustment means 40 includes a permanent magnet 41, a soft magnetic core 42 (sometimes called a stator), a coil 43, and various circuits (see FIG. 5). The rate adjustment means 40 adjusts the rate based on a detection signal detected based on the forward and reverse rotational motion of the permanent magnet 41 and a reference frequency of a crystal oscillator 70, which is a reference signal source. In the first embodiment, the crystal oscillator 70 is used as a reference signal source to achieve high frequency accuracy, but the present invention is not limited to this, and for example, a CR oscillator composed of a capacitor and a resistor may be used.

[0050] Although not shown in the drawings, the coil 43 may be arranged so as to overlap an inner frame provided inside the outer case in a plan view. Alternatively, a notch may be formed in a part of the inner frame in the circumferential direction, and the coil 43 may be arranged within the notch.

[0051] The permanent magnet 41 is a bipolar magnetized disk-shaped rotating body, and is magnetized with an N pole and an S pole in the radial direction. That is, the permanent magnet 41 is a magnet including an N pole portion 411 which is a second polarity portion, and an S pole portion 412 which is a first polarity portion having a different polarity from the second polarity portion. An insertion hole 41h through which the temperature shaft 311 is inserted is formed in the center of the permanent magnet 41. The diameter of the insertion hole 41h of the permanent magnet 41 is preferably sufficiently larger than the diameter of the portion of the temperature shaft 311 which is inserted into the insertion hole 41h of the permanent magnet 41.

[0052] The permanent magnet 41 is provided so as to perform forward and reverse rotational motion in accordance with the forward and reverse rotational motion of the balance wheel 31 (balance stem 311). That is, the permanent magnet 41 performs forward and reverse rotational motion together with the balance wheel 31 so that the rotation angle of the permanent magnet 41 is the same as the rotation angle of the balance wheel 31.

[0053] The permanent magnet 41 is preferably an isotropic magnet with its easy magnetization axis pointing in a random direction. The permanent magnet 41 is preferably magnetized by applying a magnetic field to it using a Helmholtz coil or the like while it is held by a holding member 140 (described later) attached to the balance shaft 311. By employing such a magnetization method, the magnetization direction of the permanent magnet 41 can be accurately aligned.

[0054] The soft magnetic core 42 is made of a soft magnetic material, includes a first magnetic part 421 and a second magnetic part 422, and configures a magnetic circuit together with the coil 43. The first magnetic part 421 includes a first end 421a provided facing the outer circumferential surface of the permanent magnet 41, and the second magnetic part 422 includes a second end 422a provided facing the outer circumferential surface of the permanent magnet 41. The first end 421a is a part of the first magnetic part 421 that includes a curved inner circumferential surface 421a1 that follows the outer circumferential surface of the permanent magnet 41. The second end 422a is a part of the second magnetic part 422 that includes a curved inner circumferential surface 422a1 that follows the outer circumferential surface of the permanent magnet 41.

[0055] The second end 422a is provided on the opposite side of the first end 421a across the permanent magnet 41. The first end 421a and the second end 422a are arranged to surround the outer circumferential surface of the permanent magnet 41 so as to generate magnetic resistance between them.

[0056] Here, the configuration of the soft magnetic core 42 will be described in detail, mainly with reference to Fig. 7A. The soft magnetic core 42 includes a first welded portion 423 that separates the magnetic coupling between the first end portion 421a and the second end portion 422a, and a second welded portion 424 that separates the magnetic coupling between the first end portion 421a and the second end portion 422a and is disposed opposite the first welded portion 423 via the permanent magnet 41. The first welded portion 423 and the second welded portion 424 are preferably formed in a gap that physically separates the first end portion 421a and the second end portion 422a.

[0057] The permanent magnet 41 is in a magnetically balanced position when the magnetization direction is perpendicular to the opposing direction of the first welded portion 423 and the second welded portion 424. In the first embodiment, the magnetically balanced position of the permanent magnet 41 is defined as a rotation angle of 0°.

[0058] In the first embodiment, notches are formed on the inner circumferential surface 421a1 of the first end 421a and the inner circumferential surface 422a1 of the second end 422a of the soft magnetic core 42. Specifically, notches n11 and n12 are formed on the inner circumferential surface 422a1 of the second end 422a. Also, notches n22 are formed on the inner circumferential surface 421a1 of the first end 421a, facing the notches n11 through the permanent magnet 41, and notches n21 are formed on the inner circumferential surface 421a1 of the first end 421a, facing the notches n12 through the permanent magnet 41. By forming the notches in this way, the flow of magnetic flux around the permanent magnet 41 is changed, and the magnetic influence of the soft magnetic core 42 on the permanent magnet 41 is reduced. Note that the number of notches, the intervals between each notch, and the shape of each notch are not limited to those shown in FIG. 7A.

[0059] In the first embodiment, an example in which the first end 421a and the second end 422a of the soft magnetic core 42 are integrated via the first welded portion 423 and the second welded portion 424 has been shown, but this is not limited to the example. For example, the first end 421a and the second end 422a may be magnetically decoupled via a gap without having the first welded portion 423 and the second welded portion 424. In addition, the example is not limited to being magnetically decoupled completely. For example, the first end 421a and the second end 422a may be physically connected via a narrowed portion.

[0060] As shown in Fig. 5, the rate adjustment means 40 includes a control circuit 44, a rotation detection circuit 45, a speed control pulse output circuit 46, a frequency division circuit 47, an oscillation circuit 48, and a braking circuit 80. The permanent magnet 41, the soft magnetic core 42, and the coil 43 described above are omitted from Fig. 5. The configuration of the rate adjustment means 40 shown in Fig. 5 is one example. The rate adjustment means 40 does not need to have each circuit shown in Fig. 5 independently, and it is sufficient if it can realize each function described below.

[0061] The control circuit 44 is a circuit that controls the operation of each circuit included in the rate adjusting means 40.

[0062] The control circuit 44 may perform braking control to control the braking force for braking the permanent magnet 41 by controlling the braking circuit 80. The braking force may be, for example, an electromagnetic brake that acts on the permanent magnet 41. The electromagnetic brake refers to a braking force obtained by shorting the first and second terminals of the coil 43 to create a closed loop state, and generating an induced electromotive force that generates a magnetic field in a direction that prevents a change in the magnetic flux generated in the coil 43 as the permanent magnet 41 rotates. The braking force may be applied to the permanent magnet 41 by avoiding the timing when power generation is performed. Specifically, the electromagnetic brake may be applied by avoiding the period indicated by the dashed band line in FIG. 6 in which power generation is performed.

[0063] The oscillation circuit 48 outputs a predetermined oscillation signal based on the frequency of the crystal oscillator 70. The frequency of the crystal oscillator 70 is 32768 [Hz]. The frequency divider circuit 47 divides the frequency of the oscillation signal output from the oscillation circuit 48. The frequency divider circuit 47 divides the frequency of the oscillation signal based on the crystal oscillator 70 to generate a reference signal OS that is output approximately every 1000 [ms]. However, this is not limited, and the reference signal OS may be output every 2000 [ms] or every 3000 [ms]. In other words, the reference signal OS may be output every second. Furthermore, this is not limited, and the reference signal OS may be output corresponding to the period of the speed-governing mechanism 30.

[0064] The rotation detection circuit 45 detects a detection signal based on a voltage waveform generated in the coil 43 due to the movement of the permanent magnet 41. In the first embodiment, a signal detected by the rotation detection circuit 45 due to the generation of a back electromotive force equal to or greater than a predetermined threshold is defined as the detection signal.

[0065] The speed control pulse output circuit 46 outputs a speed control pulse based on the reference signal generated by the frequency divider circuit 47 and the detection signal detected by the rotation detection circuit 45. Specifically, the detection timing of the detection signal detected by the rotation detection circuit 45 is compared with the output timing of the reference signal of about 1000 [Hz], and if there is a discrepancy between these timings, the speed control pulse output circuit 46 outputs a speed control pulse so as to bring the period at which the detection signal is detected closer to 1000 [ms] (=1 second).

[0066] The speed control pulse is output by energizing the coil 43. Therefore, the speed control pulse output circuit 46 may energize the coil 43 so that a torque acts in a direction that slows down the movement of the permanent magnet 41 when the period at which the detection signal is detected is faster than the reference signal, and may energize the coil 43 so that a torque acts in a direction that speeds up the movement of the permanent magnet 41 when the period at which the detection signal is detected is slower than the reference signal.

[0067] [Overall configuration: Governor mechanism 30 as a generator] The speed governing mechanism 30 serving as a generator in the first embodiment will be described with reference to FIG.

[0068] Fig. 6 is a diagram for explaining the relationship between the movement of the balance wheel in the first embodiment and the back electromotive force generated in the coil. In the graph in the upper part of Fig. 6, the vertical axis is the angular velocity [rad / s] of the balance wheel 31, and the horizontal axis is the measurement time [s]. In the graph in the middle part of Fig. 6, the vertical axis is the rotation angle [deg] of the balance wheel 31, and the horizontal axis is the measurement time [s]. In the graph in the lower part of Fig. 6, the vertical axis is the back electromotive force [V] generated in the coil 43, and the horizontal axis is the measurement time [s]. Each graph shown in Fig. 6 shows an example in which the movement of the balance wheel 31 (permanent magnet 41) was measured for 4 seconds.

[0069] The mechanical timepiece 1 has a power generation function that uses the principle of electromagnetic induction. In the first embodiment, the speed-regulating mechanism 30 functions as part of the generator. Specifically, the permanent magnet 41 rotates forward and backward in accordance with the forward and reverse rotation of the balance wheel 31, and power is generated by the current generated in the coil 43 based on the change in the magnetic field caused by the movement of the permanent magnet 41. The power extracted by this operating principle is used to start the power supply circuit 60. The control circuit 44 can be driven by starting the power supply circuit 60. Because this configuration is adopted, in the first embodiment, the control circuit 44 can be driven without providing a separate power source such as a battery.

[0070] The rectifier circuit 50 rectifies the current generated in the coil 43 by the motion of the permanent magnet 41 associated with the forward and reverse rotational motions of the balance wheel of the speed regulating mechanism 30. The power supply circuit 60 is a circuit including, for example, a capacitor, and stores power for driving the control circuit 44 based on the current rectified by the rectifier circuit 50.

[0071] In the first embodiment, it is preferable to generate power during the period when the permanent magnet 41 rotates in the forward direction from a rotation angle of 0° to 180° and during the period when the permanent magnet 41 rotates in the reverse direction from 0° to -180°, as shown in the lower part of Fig. 6. This is because the angular velocity of the permanent magnet 41 is fast during these periods, and therefore the detected back electromotive voltage is large, making it easy to obtain power.

[0072] [Overall configuration: Speed ​​adjustment control] With reference to FIG. 6, the rate adjustment control in the first embodiment will be described.

[0073] In the first embodiment, the speed control pulse output circuit 46 outputs a speed control pulse to control the movement of the permanent magnet 41, thereby controlling the movement of the balance wheel 31 and performing rate adjustment.

[0074] Here, when the angular velocity of the permanent magnet 41 is fast, it is difficult to adjust the rate at the desired timing. This is because there is a high possibility that the output timing of the speed control pulse will be shifted when the angular velocity of the permanent magnet 41 is fast. The state in which the angular velocity of the permanent magnet 41 is fast occurs when a large back electromotive force is generated in the coil 43. In other words, this is the timing when the rotation detection circuit 45 detects the detection signal.

[0075] Therefore, in the first embodiment, in the forward and reverse rotational motions of the permanent magnet 41, it is preferable to output a speed control pulse while the permanent magnet 41 rotates in the reverse direction from a rotation angle of 180° to 0° and while it rotates in the forward direction from a rotation angle of -180° to 0°. That is, it is preferable to output a speed control pulse in a period before the balance wheel 31 is supplied with power from the power spring 11. This makes it possible to output a speed control pulse in a state in which the angular velocity of the permanent magnet 41 is relatively slow. It is preferable that the speed control pulse is output while avoiding the period in which the above-mentioned power generation is easily obtained. That is, it is preferable that the speed control pulse is output while avoiding the period in which the permanent magnet 41 rotates in the forward direction from a rotation angle of 0° to 180° and the period in which the permanent magnet 41 rotates in the reverse direction from 0° to -180° shown in the lower part of FIG. 6.

[0076] By adopting such a configuration, it is possible to prevent the output timing of the speed control pulse from being shifted. As a result, it is possible to maintain the rate accuracy. In Fig. 6, the timing for rate adjustment is indicated by a band-shaped area. As shown in the upper graph of Fig. 6, the rate adjustment is performed during the period when the angular velocity of the permanent magnet 41 is slow.

[0077] [Torques acting on permanent magnets] In the comparative example and the first embodiment described below, the "holding torque" refers to the magnetic attraction force acting between the permanent magnet and the soft magnetic core when the coil 43 is in a non-energized state. The holding torque acts in a direction according to the arrangement of welds and notches made of non-magnetic material in the soft magnetic core made of soft magnetic material. Moreover, the "spring torque" refers to the torque generated by the elastic deformation of the hairspring. The spring torque depends on the above-mentioned Young's modulus. That is, the higher the Young's modulus of the hairspring, the larger the spring torque, and the lower the Young's modulus, the smaller the spring torque.

[0078] "Friction torque" is a torque based on friction generated at the contact surface between the pallet and the escape wheel. The friction torque acts against the spring torque of the hairspring at a position just before the 0° position when the permanent magnet returns to the 0° position due to the elastic deformation of the hairspring. "Power spring torque" is a torque based on the release of accumulated spring energy supplied from the power spring 11 to the balance wheel via the gear train. Power spring torque is a torque that acts in the forward direction when the permanent magnet rotates from the 0° position to the ±340° position.

[0079] [Torques acting on permanent magnets: Comparative examples] Before describing the torques acting on the permanent magnet 41 in the first embodiment, the torques acting on the permanent magnet 241 in the comparative example will be described with reference to Figs. 9 and 10. Fig. 9 is a plan view showing the arrangement of the permanent magnet, soft magnetic core, and tensile in the comparative example. Fig. 10 is a diagram explaining the torques acting on the permanent magnet in the comparative example. The arrows in Fig. 9 indicate the direction in which the holding torque acts. Note that in the comparative example, the configuration having the same function as the first embodiment, such as the configuration described with reference to Fig. 3, is designated by the same reference numerals and detailed description thereof will be omitted.

[0080] 9, the planar shape of the permanent magnet 241 is circular. The first end 2421a and the second end 2422a of the soft magnetic core 242 both have a shape with a semicircular inner circumferential surface, and are disposed opposite to each other via the permanent magnet 241. The first end 2421a, the second end 2422a, the first welded portion 2423, and the second welded portion 2424 of the soft magnetic core 242 are configured to form a circular opening (hole).

[0081] In the comparative example, the center position 241O of the permanent magnet 241, the center position 242O of the opening of the soft magnetic core 242, and the rotation center 2311O of the balance shaft 2311 inserted into the insertion hole 241h formed in the center of the permanent magnet 241 coincide with each other.

[0082] Fig. 9 shows permanent magnet 241 in a state where the hairspring is in a neutral position of elastic deformation. In other words, Fig. 9 shows a state where permanent magnet 241 is in a 0° position. In permanent magnet 241 in a state where it is in the 0° position, N pole portion 2411 is disposed on the second end 2422a side, and S pole portion 2412 is disposed on the first end 2421a side.

[0083] Here, for example, when the permanent magnet 241 rotates in the forward direction (counterclockwise in FIG. 9) from the state shown in FIG. 9, if the rotation angle is 0° to 90°, a holding force acts in a direction returning it to 0°. If the rotation angle is 90° to 180°, a holding force acts in a direction advancing it to 180°. If the rotation angle is 180° to 270°, a holding force acts in a direction returning it to 180°. If the rotation angle is 270° to 340°, a holding force acts in a direction advancing it to 340°.

[0084] Therefore, in the comparative example, the holding torque of the permanent magnet 241 is nearly 0 at the 0° position and the 180° position, and the permanent magnet 241 is magnetically stable.

[0085] The waveform in Fig. 10 shows the holding torque in the comparative example. The linear solid line in Fig. 10 shows the spring torque of the hairspring. The spring torque of the hairspring changes linearly with the rotation of the permanent magnet 241. For example, when the permanent magnet 241 rotates in the forward direction from a state in which the rotation angle of the permanent magnet 241 is 0°, the spring torque of the hairspring acting in the opposite direction to the rotation direction of the permanent magnet 41 increases linearly.

[0086] After the permanent magnet 241 returns from a rotation angle of 340° to 0° in response to the elastic deformation of the hairspring, it further advances to a rotation angle of -340° due to the inertial force of the balance wheel 31 and the power spring torque. Furthermore, the permanent magnet returns to 0° in response to the elastic deformation of the hairspring. In this way, the permanent magnet 241 repeats a reciprocating motion between -340° and 340°.

[0087] Here, as described above with reference to FIG. 3, when the pallet fork 22 operates to release the stop of the operation of the escape wheel 21, the escape wheel 21 resumes operation and the hands are driven. The release of the stop of the operation of the escape wheel 21 by the pallet fork 22 is performed when the impulse jewel 312a, which rotates together with the balance wheel 31, collides with the rod part 222 of the pallet fork 22. If the force with which the impulse jewel 312a collides with the rod part 222 of the pallet fork 22 is smaller than the friction (static friction force) generated on the contact surface between the inlet tines 223a or outlet tines 224a of the pallet fork 22 and the teeth of the escape wheel 21, the impulse jewel 312a cannot move the pallet fork 22. If the pallet fork 22 does not move due to the collision of the impulse jewel 312a, the escape wheel 21 cannot resume operation and the hands will stop.

[0088] Therefore, the impulse jewel 312a must collide with the rod portion 222 of the pallet fork 22 with a certain level of impact force. In order to increase the impact force of the impulse jewel 312a against the rod portion 222 of the pallet fork 22, it is advisable to increase the spring torque of the hairspring. However, if the spring torque of the hairspring is increased, it is not possible to achieve a slower vibration speed of the balance wheel 31. It is also possible to increase the moment of inertia of the balance wheel 31, but in that case, the angular velocity of the permanent magnet 41 will slow down, causing a problem of a reduced amount of power generation.

[0089] In addition, if the balance wheel temporarily stops due to an external shock or the like and loses its inertia, the balance wheel will continue to rotate only by the spring torque of the hairspring. In this case, if the spring torque of the hairspring is small compared to the holding torque, the balance wheel may stop mid-rotation.

[0090] In particular, in the comparative example, the balance wheel (permanent magnet) is likely to stop at the 180° position, which is a magnetically stable point. The dotted line in FIG. 10 indicates a straight line obtained by folding back the straight line indicating the spring torque via the horizontal axis. If this dotted line is small compared to the holding torque, the balance wheel may stop. In the example of FIG. 10, for example, if the inertia force of the balance wheel is lost near the 135° position, the permanent magnet will be affected by the holding torque and stop at the 180° position because the holding torque is larger than the spring torque.

[0091] Therefore, in the first embodiment, a configuration is adopted in which the tendency of the holding torque is changed from that shown in the comparative example, thereby reducing the spring torque of the hairspring 32 and enabling stable and sustained rotation of the balance wheel 31.

[0092] [Torques acting on permanent magnets: first embodiment] With reference to Fig. 7A, Fig. 7B, and Fig. 8, the torques acting on the permanent magnet 41 in the first embodiment will be described. Figs. 7A and 7B are plan views showing the arrangement of the permanent magnet, soft magnetic core, and tensile rod in the first embodiment. Fig. 7A shows the permanent magnet in a state where it is in a 0° position, which is a first angular position, and Fig. 7B shows the permanent magnet in a state where it is in a 180° position, which is a second angular position. Fig. 8 is a diagram for explaining the torques acting on the permanent magnet in the first embodiment. The arrows in Figs. 7A and 7B indicate the direction in which the holding torque acts.

[0093] The waveform in Fig. 8 indicates the holding torque in the first embodiment. The linear solid line in Fig. 8 indicates the spring torque of the hairspring 32. The spring torque of the hairspring 32 changes linearly with the rotation of the permanent magnet 41. For example, when the rotation angle of the permanent magnet 41 rotates in the forward direction from 0°, the spring torque of the hairspring 32 acting in the opposite direction to the rotation direction of the permanent magnet 41 increases linearly.

[0094] 8 has a waveform that acts in the reverse direction (clockwise direction) when the rotation angle of permanent magnet 41 is 0° to 180°, and acts in the forward direction (counterclockwise direction) when the rotation angle is 180° to 340°. In other words, when the rotation angle is 0° to 340°, the nodes of the waveform indicating the holding torque are only at the 0° position and the 180° position.

[0095] Therefore, when the permanent magnet 41 rotates in the forward direction from the 0° position, a holding torque acts in a direction to reverse the rotation when the rotation angle is between 0° and 180°, and a holding torque acts in a direction to advance the rotation when the rotation angle is between 180° and 340°.

[0096] Furthermore, when the permanent magnet 41 rotates in the reverse direction from the 340° position, a holding torque acts in the direction to reverse the rotation when the rotation angle is between 340° and 180°, and a holding torque acts in the direction to advance the rotation when the rotation angle is between 180° and 0°.

[0097] 8 has a waveform that acts in a forward direction (counterclockwise direction) when the rotation angle of permanent magnet 41 is 0° to -180°, and acts in a reverse direction (clockwise direction) when the rotation angle is -180° to -340°. In other words, when the rotation angle is 0° to -340°, the nodes of the waveform indicating the holding torque are only at the 0° position and the -180° position.

[0098] Therefore, when the permanent magnet 41 rotates in the reverse direction from the 0° position, a holding torque acts in a direction to reverse the rotation when the rotation angle is 0° to -180°, and a holding torque acts in a direction to advance the rotation when the rotation angle is -180° to -340°.

[0099] Furthermore, when the permanent magnet 41 rotates in the forward direction from the -340° position, a holding torque acts in a direction to reverse the rotation when the rotation angle is -340° to -180°, and a holding torque acts in a direction to advance the rotation when the rotation angle is -180° to 0°.

[0100] Therefore, in the first embodiment, the holding torque of the permanent magnet 41 is nearly zero at the 0° position, and the permanent magnet 41 is magnetically stable.

[0101] In the first embodiment, a holding torque acts in the same direction as the spring torque, that is, in the direction to advance the rotation, from ±180° before the permanent magnet 41 returns to the 0° position. That is, when the coil 43 is in a non-energized state and the permanent magnet 41 is between the 0° position and the ±180° position, a holding torque acting in a direction to rotate the permanent magnet 41 toward the 0° position always acts between the permanent magnet 41 and the soft magnetic core 42. The permanent magnet 41 returns to the 0° position with momentum due to the action of such a holding torque. Therefore, the pendulum jewel 312a collides with the rod portion 222 of the pallet fork 22 with momentum.

[0102] 8, the pallet fork 22 and the escape wheel 21 can be easily operated even if the spring torque of the hairspring 32 is reduced. Therefore, by lowering the spring torque of the hairspring 32, low-speed vibration can be achieved and the rotation of the balance wheel 31 can be stably maintained.

[0103] 8, even if the inertial force of the balance wheel 31 is lost near the 135° position due to an external shock or the like, the balance wheel 31 will rotate toward the 0° position due to the spring torque and the holding torque acting in the same direction as the spring torque. Therefore, even if the inertial force of the balance wheel 31 is lost, the balance wheel 31 can return to the 0° position with a certain degree of momentum, and the impulse jewel 312a will collide with the rod portion 222 of the pallet fork 22 with a certain degree of momentum.

[0104] Furthermore, in the first embodiment, a holding torque can be effectively applied in the direction in which the permanent magnet 41 advances between -180° and 0°, thereby increasing the angular velocity of the permanent magnet 41. As a result, the power generation efficiency can be improved.

[0105] [Arrangement of permanent magnet, soft magnetic core, and templating element] Further, the arrangement of the permanent magnet 41, the soft magnetic core 42, and the balance shaft 311 for realizing the waveform of the holding torque shown in FIG. 8 will be described in detail.

[0106] 7A and 7B, the planar shape of the permanent magnet 41 is circular. More specifically, the planar shape of the permanent magnet 41 is a perfect circle in which the distance from the center position 41O to the outer circumferential surface is equal at any position in the circumferential direction.

[0107] The first end 421a and the second end 422a of the soft magnetic core 42 both have a shape with a semicircular inner circumferential surface (the inner circumferential surface 421a1 and the inner circumferential surface 422a1), and are arranged opposite to each other via the permanent magnet 41. The first end 421a, the second end 422a, the first welded portion 423, and the second welded portion 424 of the soft magnetic core 42 are configured to form a circular opening. More specifically, the inner circumferential surface of the opening formed by the soft magnetic core 42 is a perfect circle whose distance from the center position 42O is equal at any position in the circumferential direction. Note that the inner circumferential surface of the opening formed by the soft magnetic core 42 described here means the inner circumferential surface excluding the portion where the notch is formed.

[0108] 7A shows the permanent magnet 41 in a state where the hairspring 32 is in a neutral position of elastic deformation. In other words, FIG. 7A shows the permanent magnet 41 in a state where it is in the 0° position. In the permanent magnet 41 in the 0° position, the N-pole portion 411 is disposed on the second end 422a side, and the S-pole portion 412 is disposed on the first end 421a side. In addition, in the permanent magnet 41 in the 0° position, it is preferable that the boundary between the N-pole portion 411 and the S-pole portion 412 overlaps with a virtual strip-shaped region connecting the first welded portion 423 and the second welded portion 424. With this configuration, the permanent magnet 41 is magnetically stable in the 0° position.

[0109] 7A , in the first embodiment, the center position 41O of the permanent magnet 41, which is at the 0° position, is shifted from the rotation center 311O of the temperature shaft 311, and the center position 42O of the opening of the soft magnetic core 42 is shifted from the rotation center 311O of the temperature shaft 311. In other words, the center position 41O of the permanent magnet 41 is disposed at a position different from the rotation center 311O of the temperature shaft 311, and the center position 42O of the opening of the soft magnetic core 42 is disposed at a position different from the rotation center 311O of the temperature shaft 311.

[0110] Moreover, the center position 41O of the permanent magnet 41 at the 0° position is disposed symmetrically with the center position 42O of the opening of the soft magnetic core 42 across the rotation center 311O of the balance axle 311. Moreover, the amount of shift of the center position 41O from the rotation center 311O is set to s1, the amount of shift of the center position 42O from the rotation center 311O is set to s2, and s1 and s2 are set to be the same.

[0111] In addition, when the permanent magnet 41 is in the 0° position, the center position 41O of the permanent magnet 41, the center of rotation 311O of the balance shaft 311, and the center position 42O of the opening of the soft magnetic core 42 are arranged so as to be aligned on a straight line C perpendicular to the boundary line between the N pole portion 411 and the S pole portion 412.

[0112] 7A, the center position 41O of the permanent magnet 41 is indicated by a black dot, the center position 42O of the opening of the soft magnetic core 42 is indicated by a white circle, and the rotation center 311O of the balance shaft 311 is indicated by a black dot. Note that the black dots and white circles shown in the figure are shown for the sake of convenience of explanation and do not physically exist.

[0113] 7A indicates a line that is parallel to the boundary between the N-pole portion 411 and the S-pole portion 412 and passes through the center position 41O of the permanent magnet 41. The dashed line in Fig. 7A indicates a line that is parallel to the boundary between the N-pole portion 411 and the S-pole portion 412 and passes through the center position 42O of the opening of the soft magnetic core 42. The solid line in Fig. 7A indicates a line that is parallel to the boundary between the N-pole portion 411 and the S-pole portion 412 and passes through the rotation center 311O of the balance shaft 311.

[0114] The interval d1, which is the second interval between the outer circumferential surface of the N-pole portion 411 of the permanent magnet 41 at the 0° position and the inner circumferential surface 422a1 of the second end 422a, is relatively small. On the other hand, the interval d2 (>d1), which is the first interval between the outer circumferential surface of the S-pole portion 412 of the permanent magnet 41 at the 0° position and the inner circumferential surface 421a1 of the first end 421a, is relatively large. The interval d1 shown in FIG. 7A is the interval at the position where the permanent magnet 41 and the second end 422a at the 0° position are closest in the radial direction. The interval d2 shown in FIG. 7A is the interval at the position where the permanent magnet 41 and the first end 421a at the 0° position are furthest in the radial direction. With this arrangement, a relatively large holding torque acts on the permanent magnet 41 in the direction toward the 0° position.

[0115] 7B shows a state where the permanent magnet 41 is rotated 180° in the positive direction from the state shown in FIG. 7A. As shown in FIG. 7B, when the permanent magnet 41 is at the 180° position, the center position 41O of the permanent magnet 41 coincides with the center position 42O of the opening of the soft magnetic core 42. Therefore, the interval between the outer peripheral surface of the permanent magnet 41 and the inner peripheral surface of the soft magnetic core 42 becomes uniform in the circumferential direction. That is, at the 180° position, the S-pole portion 412 faces the second end 422a with a third interval d4 therebetween, and the N-pole portion 411 faces the first end 421a with a fourth interval d3 therebetween, and the intervals d4 and d3 are equal to each other.

[0116] The intervals d3 and d4 are larger than the interval d1 and smaller than the interval d2. With this arrangement, a relatively small holding torque acts on the permanent magnet 41 in the direction toward the 180° position. Note that the intervals d3 and d4 do not necessarily have to be the same, and it is preferable that at least the difference between the intervals d3 and d4 is smaller than the difference between the intervals d1 and d2.

[0117] In the first embodiment, the shift amounts s1 and s2 are set so that the holding torque that tends to stabilize at the 0° position is sufficiently larger than the holding torque that tends to stabilize at the 180° position. In other words, the shift amounts s1 and s2 are set so that the holding torque is stable at the 0° position and unstable at the 180° position. This makes it possible to realize the waveform of the holding torque shown in FIG. 8.

[0118] In the first embodiment, an example is shown in which a holding torque acts in a direction to advance rotation from ±180° before the permanent magnet 41 returns to the 0° position, but this is not limited to this. The shift amounts s1 and s2 can be set so that a holding torque acts in a direction to advance rotation from at least ±135° before the permanent magnet 41 returns to the 0° position.

[0119] In addition, in Figure 7A, the distance between the outer peripheral surface of the N-pole portion 411 of the permanent magnet 41 and the inner peripheral surface 422a1 of the second end 422a of the soft magnetic core 42 at the closest position is shown as distance d1, and the distance between the outer peripheral surface of the S-pole portion 412 of the permanent magnet 41 and the inner peripheral surface 421a1 of the first end 421a of the soft magnetic core 42 at the farthest position is shown as distance d2, but this is not limited to this.

[0120] The distance d1 may be the distance between the N-pole portion 411 and the second end 422a on a normal line to the outer circumferential surface of the N-pole portion 411 in a planar view at any position in the circumferential direction of the N-pole portion 411. The distance d2 may be the distance between the S-pole portion 412 and the first end 421a on a normal line to the outer circumferential surface of the S-pole portion 412 in a planar view at any position in the circumferential direction of the S-pole portion 412.

[0121] In the first embodiment, when the permanent magnet 41 is at the 0° position, the distance d1 between the outer circumferential surface of the N-pole portion 411 and the inner circumferential surface 422a1 of the second end 422a is narrower than the distance d2 between the outer circumferential surface of the S-pole portion 412 and the inner circumferential surface 421a1 of the first end 421a at any position in the circumferential direction of the permanent magnet 41. Therefore, at any position in the circumferential direction of the permanent magnet 41, the difference between the distance d1 between the outer circumferential surface of the N-pole portion 411 and the inner circumferential surface 422a1 of the second end 422a and the distance d2 between the outer circumferential surface of the S-pole portion 412 and the inner circumferential surface 421a1 of the first end 421a is greater than 0. On the other hand, as described above, when the permanent magnet 41 is at the 180° position, the difference in the distance between the outer circumferential surface of the permanent magnet 41 and the inner circumferential surface of the opening of the soft magnetic core 42 is 0 at any two positions in the circumferential direction of the permanent magnet 41. That is, in the configuration of the first embodiment, the difference between the distance between the N-pole portion 411 and the soft magnetic core 42 and the distance between the S-pole portion 412 and the soft magnetic core 42 is smaller when the permanent magnet 41 is at the 180° position than when it is at the 0° position.

[0122] By adopting the configuration described above, the holding torque has the tendency shown in Fig. 8. Therefore, it is possible to reduce the spring torque of the hairspring 32 and to make it possible to stably sustain the rotation of the balance wheel 31.

[0123] [Eccentric structure] Next, with reference to FIGS. 11 to 18C, the details of the eccentric structure for realizing the arrangement configuration shown in FIGS. 7A and 7B will be described.

[0124] [Eccentricity structure: eccentricity of 41 permanent magnets] Fig. 11 is a perspective view showing each member that rotates together with the balance shaft in the first embodiment. Fig. 12 is an exploded perspective view showing each member shown in Fig. 11 in an exploded state. Fig. 13 is a perspective view showing the bottom of the holding member in the first embodiment. Fig. 14A is a perspective view showing the holding member in the first embodiment. Fig. 14B is a plan view showing the holding member in the first embodiment. Fig. 15 is an exploded perspective view showing the balance shaft and the swing seat in an exploded state.

[0125] 11 and 12, the permanent magnet 41 is housed in a holding member 140 and is thereby held by the holding member 140. As shown in Figures 14A and 14B, the holding member 140 includes a bottom 141 having a circular planar shape and a cylindrical side wall 142 standing up from the bottom 141. The inner diameter of the side wall 142 is approximately the same as the outer diameter of the permanent magnet 41, and the permanent magnet 41 rotates integrally with the holding member 140 by being press-fitted into the side wall 142.

[0126] An insertion hole 141a through which the balance shaft 311 is inserted is formed in the bottom portion 141. In addition, a positioning groove 141b is formed in the lower surface of the bottom portion 141 as shown in FIG.

[0127] The balance shaft 311 has a fitting portion 311c that fits into the positioning groove 141b when inserted into the insertion hole 141a of the bottom portion 141. When the fitting portion 311c fits into the positioning groove 141b, the rotation center 311O of the balance shaft 311 is positioned relative to the center position 41O of the permanent magnet 41, and the holding member 140 rotates integrally with the balance shaft 311.

[0128] A center position 141aO of the insertion hole 141a coincides with a rotation center 311O of the balance shaft 311. As shown in Fig. 14B, the center position 141aO of the insertion hole 141a is shifted from the center position 141O of the circular bottom portion 141. Therefore, the center position 41O of the permanent magnet 41 housed in the holding member 140 is shifted from the rotation center 311O of the balance shaft 311 inserted into the insertion hole 141a.

[0129] The balance wheel 31 also includes a roller bearing 312 at its center. A roller jewel 312a is fixed to the roller bearing 312. As shown in Fig. 15, the roller bearing 312 includes an insertion hole 312b through which the balance stem 311 is inserted, and a positioning groove 312c into which the fitting portion 311d of the balance stem 311 fits. With this configuration, the roller jewel 312a is positioned relative to the rotation center 311O of the balance stem 311, and the roller jewel 312a rotates in conjunction with the rotation of the balance wheel 31.

[0130] [Eccentric structure: eccentricity of soft magnetic core 42] Fig. 16 is a perspective view showing the soft magnetic core and its peripheral members in the first embodiment. Fig. 17 is an exploded perspective view showing the soft magnetic core shown in Fig. 16 disassembled from the support member. Fig. 18A is a perspective view showing the positioning frame of the first embodiment. Fig. 18B is a plan view showing the positioning frame of the first embodiment. Fig. 18C is a perspective view showing the positioning frame of the first embodiment.

[0131] The soft magnetic core 42 is supported by a support member 33. The support member 33 is fixed to the base plate 10. That is, the soft magnetic core 42 is fixed to the base plate 10 via the support member 33. The support member 33 has an opening 33a formed therein that corresponds to the opening of the soft magnetic core 42.

[0132] The mechanical timepiece 1 has a positioning frame 35 that is attached to the support member 33 and positions the soft magnetic core 42 relative to the support member 33. As shown in Fig. 18A, the positioning frame 35 has a shape that includes a fitting portion 351 and an annular protrusion 352 that is a positioning protrusion.

[0133] 18B, the fitting portion 351 has an octagonal planar shape. The positioning frame 35 is positioned relative to the support member 33 by fitting the fitting portion 351 into the opening 33a of the support member 33. The planar shape of the fitting portion 351 is not limited to an octagon, and may be any shape that fits into the opening 33a and restricts displacement in the circumferential direction.

[0134] The annular protrusion 352 fits into the opening of the soft magnetic core 42 to position the soft magnetic core 42 .

[0135] 18B, the center position 352O of the annular protrusion 352 is disposed so as to be shifted from the center position 351O of the fitting portion 351. The center position 351O of the fitting portion 351 is disposed so as to coincide with the rotation center 311O of the balance shaft 311. The center position 352O of the second annular protrusion 452 is disposed so as to coincide with the center position 42O of the opening of the soft magnetic core 42. The center position 351O of the fitting portion 351 coincides with the center position of the outer shape of the positioning frame 35.

[0136] With this configuration, the center position 42O of the opening of the soft magnetic core 42 is disposed so as to be shifted from the rotation center 311O of the balance shaft 311.

[0137] 7A, the center position 42O of the opening of the soft magnetic core 42 needs to be located symmetrically to the center position 41O of the permanent magnet 41, which is located at the 0° position, across the rotation center 311O of the balance shaft 311. However, in the state where the soft magnetic core 42 and the support member 33 are assembled as shown in FIG. 16, it is difficult to determine the circumferential position of the positioning frame 35.

[0138] Therefore, in the first embodiment, as shown in Fig. 18C, a notch 355 is formed on the opposite side to the protruding direction of the fitting portion 351 and the annular projection 352. When positioning the positioning frame 35 in the circumferential direction, the person making the mechanical timepiece 1 can perform positioning while visually checking the notch 355 so that the notch 355 is located at a predetermined position in the circumferential direction. Note that instead of the notch 355, a visible mark or the like may be provided.

[0139] [Bearing structure] Next, the bearing structure in the first embodiment will be described with reference to Figs. 19 to 21. Fig. 19 is a perspective view showing the bearing structure in the first embodiment and its peripheral members. Fig. 20 is a perspective view showing the stone holding member in the first embodiment. Fig. 21 is a plan view showing the stone holding member in the first embodiment and its peripheral members. Note that in Fig. 21, the positioning frame 35, the stone 333, etc. are omitted.

[0140] 19, a bearing structure 330 is disposed inside the above-mentioned positioning frame 35. The bearing structure 330 is a structure that supports one end of the balance shaft 311.

[0141] The bearing structure 330 includes at least a jewel 333 and a jewel holding member 334 that holds the jewel 333. The jewel 333 abuts against one end of the balance shaft 311, thereby positioning the balance shaft 311 in the axial direction. The jewel holding member 334 is an annular member that surrounds at least a portion of the outer circumferential surface of the permanent magnet 41.

[0142] In the first embodiment, the jewel holding member 334 is made of a magnetic material such as carbon tool steel (SK material) containing carbon.

[0143] In the first embodiment, as shown in Fig. 20, a notch 334a is formed in a part of the stone holding member 334. Specifically, the notch 334a is formed in a part of the stone holding member 334 that faces the outer peripheral surface of the permanent magnet 41.

[0144] By employing such a stone holding member 334, it is possible to change the flow of magnetic flux generated around the permanent magnet 41. As a result, it is possible to affect the holding torque acting on the permanent magnet 41. The reason why the holding torque is affected is due to the same principle as that of the notches n11, n12, n21, and n22 formed in the soft magnetic core 42. That is, this is because the part of the stone holding member 334 where the magnetic material is present and the part where the magnetic material is not present (cutout 334a) are positioned opposite the outer peripheral surface of the permanent magnet 41.

[0145] Further, the holding member 334 has a notch 334b ​​formed on the side opposite to the side on which the notch 334a is formed, at a position corresponding to the notch 334a in the circumferential direction. Fig. 21 shows an example in which the notches 334b ​​are formed at positions facing the N-pole portion 411 and the S-pole portion 412 of the permanent magnet 41 at the 0° position in a plan view. That is, in Fig. 21, the notches 334a are formed at positions facing the N-pole portion 411 and the S-pole portion 412 of the permanent magnet 41 at the 0° position.

[0146] The jewel holding member 334 is provided so as to be rotatable in the rotation direction of the permanent magnet 41 from the state shown in FIG. 21, and the position of the notch 334a can be changed according to the angular position. In the first embodiment, the holding torque can be finely adjusted according to the position of the notch 334a. When adjusting the angular position of the jewel holding member 334, the person making the mechanical timepiece 1 can adjust while visually checking the notch 334b ​​so that the notch 334a is positioned at a predetermined position in the circumferential direction. Note that a visible mark or the like may be provided instead of the notch 334b.

[0147] By adopting a configuration in which the holding torque can be finely adjusted using the stone holding member 334 made of a magnetic material in this manner, it is possible to suppress errors in the holding torque that may arise due to individual differences.

[0148] Although FIG. 20 shows an example in which the notches 334a are formed in two locations, the present invention is not limited to this example, and the notches 334a may be formed in one location, or in three or more locations.

[0149] [Variations] Next, each modified example of the first embodiment will be described with reference to Figs. 22 to 24. The tendency of the holding torque described in the first embodiment can also be realized by the configuration of each modified example below. That is, if the configuration is such that the second interval d1 is smaller than the first interval d2, and the difference between the third interval d4 and the fourth interval d3 is smaller than the difference between the interval d2 and the interval d1, the holding torque shown in Fig. 8 can be obtained. Note that in each modified example, components having the same functions as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0150] 22 to 24 show an example in which no notch is formed in the soft magnetic core 42, but a notch may be formed in the same manner as in the configuration shown in FIG. 7A.

[0151] [First Modification] FIG. 22 is a plan view showing an arrangement of permanent magnets, soft magnetic cores, and a rotor in a first modified example of the first embodiment.

[0152] In the first modified example, the planar shape of the permanent magnet 41 is a shape in which a part of a perfect circle is cut out. Specifically, a part of the S-pole portion 412 is cut out. By adopting such a configuration, at the 0° position, the distance d1 between the N-pole portion 411 and the second end 422a is smaller than the distance d2 between the S-pole portion 412 and the first end 421a.

[0153] In the first modified example, the center position 41O of the permanent magnet 41 at the 0° position is aligned with the rotation center 311O of the temperature shaft 311, and the center position 42O of the soft magnetic core 42 is shifted from the rotation center 311O of the temperature shaft 311. The amount of deviation of the center position 42O of the soft magnetic core 42 from the rotation center 311O of the temperature shaft 311 is designated as s1.

[0154] With this configuration, when rotated 180° in the positive direction from the state shown in Figure 22, the difference between the distance d4 between the S pole portion 412 and the second end 422a and the distance d3 between the N pole portion 411 and the first end 421a is smaller than the difference between the distance d2 and the distance d1.

[0155] [Second modified example] FIG. 23 is a plan view showing an arrangement of permanent magnets, soft magnetic cores, and a rotor in a second modified example of the first embodiment.

[0156] In the second modified example, the center position of an insertion hole 41h formed in the center of the permanent magnet 41, through which the balance shaft 311 is inserted, coincides with the rotation center 311O of the balance shaft 311. The configuration of the second modified example is similar to that of the first embodiment, except that the position of the insertion hole 41h formed in the center of the permanent magnet 41 is different. That is, the positional relationship between the center position 41O of the permanent magnet 41, the center position 42O of the opening of the soft magnetic core 42, and the rotation center 311O of the balance shaft 311 is similar to that of the first embodiment.

[0157] [Third Modification] FIG. 24 is a plan view showing an arrangement of permanent magnets, soft magnetic cores, and a rotor in a third modified example of the first embodiment.

[0158] In the third modified example, when the permanent magnet 41 is at the 0° position, the center position 42O of the opening of the soft magnetic core 42 is aligned with the rotation center 311O of the temperature shaft 311, and the center position 41O of the permanent magnet 41 is shifted from the rotation center 311O of the temperature shaft 311. In the third modified example, the planar shape of the opening of the soft magnetic core 42 is elliptical. Specifically, the semicircular arc formed by the first end 421a is larger than the semicircular arc formed by the second end 422a. The amount of shift of the center position 41O of the permanent magnet 41 from the rotation center 311O of the temperature shaft 311 is set to s1.

[0159] With this configuration, when rotated 180° in the positive direction from the state shown in Figure 24, the difference between the distance d4 between the N-pole portion 411 and the first end 421a and the distance d3 between the S-pole portion 412 and the second end 422a is smaller than the difference between the distance d2 and the distance d1.

[0160] [Second embodiment] Next, a mechanical timepiece according to a second embodiment will be described. Note that in the mechanical timepiece according to the second embodiment, the overall configuration is the same as that shown in Fig. 1 and Fig. 5, and the eccentric structure is also the same as that shown in Fig. 7A, Fig. 7B, Fig. 11 to Fig. 15, etc. Therefore, the same reference numerals are used for configurations having the same functions as those in the first embodiment, and detailed descriptions thereof will be omitted.

[0161] Fig. 25 is a diagram for explaining each torque acting on the permanent magnet in the second embodiment. The power spring torque and friction torque in Fig. 25 are similar to the torques explained with reference to Fig. 8, and therefore detailed explanations thereof will be omitted.

[0162] One of the thick solid lines in Fig. 25 indicates the holding torque in the second embodiment. The other of the thick solid lines in Fig. 25 indicates the spring torque of the hairspring 232 in the second embodiment. The dotted line in Fig. 25 indicates a line obtained by folding back the line indicating the spring torque in the second embodiment via the horizontal axis.

[0163] In the second embodiment, the forward and reverse rotational motion of the balance wheel 31 (balance arbour 311) includes at least a period in which the balance wheel 31 rotates idly relative to the hairspring 232 and a period in which the hairspring 232 transmits a rotational force to the hairspring 232 and elastically deforms the hairspring 232. In other words, the spring torque of the hairspring 232 includes a period in which the spring torque changes linearly with the rotation of the permanent magnet 41 (balance arbour 311) and a period in which the spring torque does not change. Specifically, the spring torque of the hairspring 232 is 0 during the period from when the rotation angle of the permanent magnet 41 reaches 135° from 0°, and the spring torque of the hairspring 32 acting in the opposite direction to the rotation direction of the permanent magnet 41 increases linearly after 135°. After the rotation angle of the permanent magnet 41 reaches 345°, the permanent magnet 41 (balance wheel 31) rotates in the direction returning to the rotation angle of 0° in response to the elastic deformation of the hairspring 232.

[0164] Similarly, the spring torque of the hairspring 232 is 0 during the period from 0° until the rotation angle of the permanent magnet 41 reaches -135°, and the spring torque of the hairspring 32 acting in the direction opposite to the rotation direction of the permanent magnet 41 increases linearly after -135°. After the rotation angle of the permanent magnet 41 reaches -345°, the permanent magnet 41 (balance wheel 31) rotates in the direction returning to the rotation angle of 0° in response to the elastic deformation of the hairspring 232.

[0165] As described above, in the second embodiment, since there is a period in which the spring torque of the hairspring 232 does not act, it is possible to realize even slower vibration than in the first embodiment. Also, in the second embodiment, since an eccentric structure is adopted like the first embodiment, it is possible to reduce the spring torque of the hairspring 232 and to make it possible to stably sustain the rotation of the balance wheel 31 by receiving the action of the holding torque.

[0166] Next, the details of the configuration for realizing the spring torque shown in Fig. 25 will be described with reference to Figs. 26 to 28. Fig. 26 is an exploded perspective view showing a balance wheel, balance arbour, permanent magnet, hairspring and peripheral members in the second embodiment. Fig. 27 is a perspective view showing a holding member in the second embodiment. Fig. 28 is a cross-sectional view showing the balance wheel, balance arbour, permanent magnet, hairspring and holding members in the second embodiment.

[0167] In the second embodiment, the permanent magnet 41 is held by a holding member 340. The holding member 340 includes a bottom 341 and a cylindrical side wall 342 standing up from the bottom 341. The inner diameter of the side wall 342 is approximately the same as the outer diameter of the permanent magnet 41, and the permanent magnet 41 rotates integrally with the holding member 340 by being press-fitted into the side wall 342. The bottom 341 is formed with an insertion hole 341a through which the balance shaft 311 is inserted. In addition, a positioning groove 341b is formed on the lower surface of the bottom 341 as shown in Figs. 27 and 28. The fitting portion 311c of the balance shaft 311 fits into the positioning groove 341b in a state where it is inserted into the insertion hole 341a of the bottom 341. By fitting the fitting portion 311c into the positioning groove 341b, the rotation center of the balance shaft 311 is positioned relative to the center position of the permanent magnet 41, and the holding member 340 rotates integrally with the balance shaft 311.

[0168] As shown in FIG. 26, a hairspring 232 of the second embodiment includes an outer end portion 232a, an inner end portion 232b, a spiral spring portion 232c, and a connection portion 232d that connects the inner end portion 232b and the spring portion 232c.

[0169] An outer end 232a of the hairspring 232 is fixed to the hairspring holder 34. On the other hand, an inner end 232b of the hairspring 232 is not fixed to the balance arbour 311. An opening 232bh through which the balance arbour 311 is inserted is formed in the inner end 232b. As shown in FIG. 28, the inner diameter of the opening 232bh is preferably slightly larger than the outer diameter of the portion of the balance arbour 311 that faces the opening 232bh when inserted through the opening 232bh. Due to this configuration, the balance arbour 311 includes a period during which it rotates idly relative to the hairspring 232 during its forward and reverse rotational motion.

[0170] Furthermore, the holding member 340 has a protrusion 345 which is a contact portion extending in a direction opposite to the direction in which the side wall portion 342 protrudes. The protrusion 345 is provided so as to be located in the gap G between the inner end portion 232b and the spring portion 232c of the hairspring 232. The protrusion 345 is movable in the gap G between the inner end portion 232b and the spring portion 232c as the balance axle 311 rotates. The connecting portion 232d may be shaped to connect the inner end portion 232b and the spring portion 232c so as to form a gap G between the inner end portion 232b and the spring portion 232c that allows the protrusion 345 to move.

[0171] As the holding member 340 rotates integrally with the balance shaft 311, the protrusion 345 moves within the gap G. Then, when the angle of the balance shaft 311 (balance wheel 31) reaches a predetermined angle, the protrusion 345 hits the connection portion 232d. As a result, the rotational force from the holding member 340 is transmitted to the connection portion 232d, and the connection portion 232d rotates together with the holding member 340. In addition, the spring portion 232c is elastically deformed in accordance with the rotation of the connection portion 232d. As a result, a spring torque is generated.

[0172] As shown in Fig. 26, the planar shape of the connection portion 232d may be a sector expanding radially outward. The period during which the balance arbour 331 rotates idly relative to the hairspring 232 may be determined according to the extent to which the sector of the connection portion 232d expands. When the sector of the connection portion 232d expands greatly, the period during which the balance arbour 331 rotates idly relative to the hairspring 232 becomes shorter, and the spring torque becomes larger. On the other hand, when the sector of the connection portion 232d expands only slightly, the period during which the balance arbour 331 rotates idly relative to the hairspring 232 becomes longer, and the spring torque becomes smaller.

[0173] Furthermore, with reference to Fig. 29A to Fig. 29E, a specific example of the operation of the hairspring for each rotation angle of the balance wheel in the second embodiment will be described. Fig. 29A shows a state in which the rotation angle of the balance wheel is 0°. Fig. 29B shows a state in which the rotation angle of the balance wheel is 135°. Fig. 29C shows a state in which the rotation angle of the balance wheel is 315°. Fig. 29D shows a state in which the rotation angle of the balance wheel is -135°. Fig. 29E shows a state in which the rotation angle of the balance wheel is -315°. Note that in Fig. 29A to Fig. 29E, the clockwise direction is taken as the positive direction.

[0174] 29A to 29E show a state seen from the permanent magnet 41 side (upper side in FIG. 28) rather than hairspring 232. In FIG. 29A to 29E, protrusion 345 is shown by imaginary lines. Note that although the shape of spring portion 232c of hairspring 232 changes as it expands and contracts, the change in the shape of hairspring 232 is not depicted in FIG. 29A to 29E.

[0175] When the balance wheel 31 rotates clockwise in the figure from a state where the rotation angle is 0°, it changes from the state shown in Fig. 29A to the state shown in Fig. 29B, and then to the state shown in Fig. 29C. Since the protrusion 345 is not in contact with the connection part 232d until the state shown in Fig. 29A changes to the state shown in Fig. 29B, the rotational force of the balance wheel 31 (balance arbour 311) is not transmitted to the hairspring 232.

[0176] Thereafter, when the rotation angle of the balance wheel 31 reaches 135°, the protrusion 345 hits the connection part 232d. As a result, the connection part 232d of the hairspring 232 rotates in the clockwise direction in the figure in conjunction with the rotation of the protrusion 345. As the connection part 232d rotates, the spring part 232c elastically deforms, generating spring torque. After the rotation angle of the balance wheel 31 reaches 345°, the balance wheel 31 rotates in the counterclockwise direction in the figure in conjunction with the elastic deformation of the hairspring 232.

[0177] Furthermore, when the rotation angle of the balance wheel 31 rotating counterclockwise in the figure reaches 135°, the protrusion 345 separates from the connection part 232d and continues to rotate. After this, the balance wheel 31 continues to rotate as the permanent magnet 41 is subjected to the action of the holding torque. When the balance wheel 31 rotating counterclockwise in the figure passes through a rotation angle of 0° and reaches a rotation angle of -135°, the protrusion 345 collides with the connection part 232d. As a result, the connection part 232d of the hairspring 232 rotates counterclockwise in the figure with the rotation of the protrusion 345. With the rotation of the connection part 232d, the spring part 232c is elastically deformed, and a spring torque is generated. After the rotation angle of the balance wheel 31 reaches -345°, the balance wheel 31 rotates clockwise in the figure with the elastic deformation of the hairspring 232.

[0178] The balance wheel 31 repeats the forward and reverse rotational motion described above. During this time, periods in which the spring torque of the hairspring 232 is generated and periods in which it is not generated are repeated. As a result, the spring torque shown in FIG. 25 can be obtained.

[0179] In the second embodiment, an example has been described in which the protrusion 345 comes into contact with the connecting portion 232d when the rotation angle of the balance wheel 31 rotating in the clockwise direction in the drawing is 135° or more, but this is not limited to the above. There should be a period during which the protrusion 345 is not in contact with the connecting portion 232d at least while the rotation angle of the balance wheel 31 is equal to or more than 0° and less than 180°. The same applies to the counterclockwise direction.

[0180] In the second embodiment, the spacing between the permanent magnet 41 and the soft magnetic core 42, the spacing between the notches n11, n12, n21, and n22, and the shapes of the notches n11, n12, n21, and n22 are adjusted so that the holding torque also increases in a similar manner to the gradient at which the spring torque of the hairspring 232 increases after 135° as shown in Fig. 25. This allows the spring torque and the holding torque to largely cancel each other out, achieving even lower vibrations than in the first embodiment.

[0181] In the second embodiment, the amount of deformation of the hairspring 232 can be reduced compared to the first embodiment, so the pitch of the hairspring 232 can be designed to be smaller. This allows the hairspring 232 and the balance wheel 31 to be made smaller, and the shape and material of the hairspring 232 can be selected with greater freedom. Furthermore, as shown in FIG. 25, the slope of the spring torque can be made larger compared to FIG. 8 of the first embodiment, and the rigidity can be improved by widening the width of the spring portion 232c of the hairspring 232 or shortening the hair length. The improved rigidity of the hairspring 232 makes it easier to handle the hairspring 232 during assembly.

[0182] [Modification of the second embodiment] Fig. 30A is a perspective view showing a protrusion in a modified example of the second embodiment, and Fig. 30B is a cross-sectional view showing the case where the protrusion in the modified example of the second embodiment is used.

[0183] 27 and the like show an example in which the holding member 340 includes the protrusion 345 which is the contact portion, but this is not limiting. That is, the protrusion 345 may be provided on a member separate from the holding member 340.

[0184] 30A and 30B show an example in which a contact member 500 is used. The contact member 500 includes a frame portion 510 in which an insertion hole 510h through which the temperature shaft 311 is inserted is formed, and a protrusion portion 520 located on the outer side of the frame portion 510.

[0185] 27 and the like. The contact member 500 rotates integrally with the balance arbour 311. When the contact member 500 rotates, the protrusion 520 collides with the connection portion 232d of the hairspring 232, and the rotational force of the balance arbour 311 is transmitted to the hairspring 232.

[0186] 30B shows an example in which hairspring 232 is provided between contact member 500 and holding member 340, but is not limited thereto. For example, contact member 500 may be provided between hairspring 232 and holding member 340. In this case, protrusion 520 may protrude in the opposite direction to the direction shown in FIG. 30B.

[0187] Although detailed description will be omitted, the configurations of the second embodiment and its modified example may be combined with the configurations of the first to third modified examples of the first embodiment described with reference to FIGS.

[0188] [others] Fig. 31 is a perspective view showing a modified example of the holding member. Fig. 11 and other figures have been used to explain an example in which the permanent magnet 41 has an eccentric structure. That is, an example has been explained in which the central position 41O of the permanent magnet 41 housed in the holding member 140 is arranged offset from the rotation center 311O of the balance shaft 311 inserted into the insertion hole 141a. In such a configuration, the center of gravity of the rotor formed of the permanent magnet 41 and the holding member 140 is offset from the rotation center. This may affect the attitude of the permanent magnet 41.

[0189] The holding member 440 shown in Fig. 31 has a center-of-gravity adjusting portion 445 provided on the side wall portion 342. The center-of-gravity adjusting portion 445 is a portion provided for adjusting the center of gravity of a rotating body formed of the permanent magnet 41 and the holding member 440. As shown in Fig. 31, it is preferable that the center-of-gravity adjusting portion 445 is provided on a side closer to the rotation center 311O of the balance shaft 311 in the circumferential direction.

[0190] 31 is merely an example and is not limiting. For example, the center-of-gravity adjusting portion 445 does not need to be a part of the holding member 440 and may be a separate member from the center-of-gravity adjusting portion 445. Also, a notch or groove may be formed in the holding member 440 as the center-of-gravity adjusting portion. In this case, the notch or groove may be formed on the side farther from the rotation center 311O of the balance shaft 311 in the circumferential direction.

[0191] FIG. 32 is a perspective view showing a modified example of the permanent magnet. In FIG. 11, FIG. 28, etc., an example in which the permanent magnet 41 rotates together with the balance shaft 311 via the holding members 140, 340 has been described, but the present invention is not limited to this, and the permanent magnet 41 may be directly attached to the balance shaft 311. In this case, as shown in FIG. 32, the center of the insertion hole 41h (i.e., the rotation center 311O of the balance shaft) may be shifted from the center position 41O of the circular permanent magnet 41. In addition, the balance shaft may be press-fitted into the insertion hole 41h, so that the permanent magnet 41 can rotate integrally with the balance shaft. When no holding member is used and the permanent magnet 41 shown in FIG. 32 is used, the contact member 500 shown in FIG. 30A may be used. The insertion hole 41h may be shifted to either the N pole side or the S pole side.

[0192] 33 is a diagram for explaining a modified example of the arrangement angle of the permanent magnet and the soft magnetic core. In the escapement 20, due to mechanical error, the static friction force generated on the contact surface between the recessed pawl 223a and the teeth of the escape wheel 21 and the static friction force generated on the contact surface between the recessed pawl 224a and the teeth of the escape wheel 21 may be different in magnitude. For example, if the static friction force is large on the recessed pawl 224a side, when the balance wheel 31 returns to 0° from the positive rotation angle, the holding torque against the static friction force generated on the contact surface between the recessed pawl 224a and the escape wheel 21 is insufficient, and there is a risk that the escape wheel 21 will not be released.

[0193] In this way, when there is an imbalance between the static frictional forces on the recessed claw 223a side and the protruding claw 224a side, it is advisable to tilt the eccentric direction of the permanent magnet 41 and the soft magnetic core 42. FIG. 33 shows an example in which the eccentric direction of the permanent magnet 41 and the soft magnetic core 42 is tilted by 10° from the arrangement in the first embodiment. The balance wheel 31 and the hairspring 32 are also tilted by 10° from the arrangement in the first embodiment. Here, the eccentric direction is the direction in which the center position of the permanent magnet 41 and the center position of the opening of the soft magnetic core 42 are shifted from the rotation center of the balance arbour 311. In other words, it is the direction in which a line connecting the rotation center of the balance arbour 311 and the center position of the permanent magnet 41 extends.

[0194] By adopting such an arrangement, as shown in the lower graph of Fig. 33, the holding torque is generated with a delay of 10° in the positive rotation direction compared to the graph of Fig. 8 in the first embodiment. Note that since the relative positions of the permanent magnet 41 and the soft magnetic core 42 are the same as in the first embodiment, the waveform of the holding torque itself is almost the same as in Fig. 8.

[0195] The graph in the lower part of Fig. 33 shows an example in which a holding torque T1 occurs at the timing when the static friction force on the protruding claw 224a side occurs, and a holding torque T2 occurs at the timing when the static friction force on the recessed claw 223a side occurs. By adopting the arrangement shown in the upper part of Fig. 8, the timing when the holding torque occurs is shifted, so that T1>T2. Therefore, it is easier to release the escape wheel 21 on the protruding claw 224a side where the static friction force is large.

[0196] As described above, even if an imbalance occurs in the static friction forces between the recessed pawl 223a side and the protruding pawl 224a side, the escapement 20 can be operated normally by adopting the arrangement shown in FIG. 33. Note that FIG. 33 shows an example in which the eccentric directions are shifted by 10° so that the holding torque is large at the timing when the static friction force is generated on the protruding pawl 224a side, but this is not limited to this. The eccentric direction may be appropriately set depending on which of the recessed pawl 223a side and the protruding pawl 224a side has a larger static friction force and how much the static friction forces differ from each other. Note that the arrangement shown in FIG. 33 is not limited to the first embodiment, and can also be applied to the second embodiment and their modified examples.

[0197] FIG. 34 is a plan view showing a modified example of the hairspring. The hairspring 1232 shown in FIG. 34 is a modified example of the hairspring 232 shown in FIG. 26 and the like. The hairspring 1232 includes an outer end portion 1232a, an inner end portion 1232b, a spiral spring portion 1232c, and a connecting portion 1232d that connects the inner end portion 1232b and the spring portion 1232c. The planar shape of the connecting portion 1232d includes a portion that expands radially outward. The connecting portion 1232d determines the period during which the balance arbour 311 rotates idly with respect to the hairspring 1232 according to the degree of expansion of the shape of the portion that expands radially outward.

[0198] In the above-described second embodiment, an example in which the planar shape of the connecting portion 232d is fan-shaped has been described. However, when the planar shape of the connecting portion 232d is fan-shaped, the contraction range of the spring portion 232c may be restricted by the connecting portion 232d when the spring portion 232c contracts. Therefore, in the hairspring 1232 shown in FIG. 34, a configuration is adopted in which the allowable amount of contraction of the spring portion 1232c is larger than that of the fan-shaped hairspring 232. Specifically, the planar shape of the connecting portion 1232d is a shape including a portion in which the distance from the rotation center of the hairspring 1232 to the radial end is shorter than the radius of the rotation locus of the outermost portion of the connecting portion 1232d in the radial direction. The outermost portion of the connecting portion 1232d is preferably the portion farthest from the rotation center of the hairspring 1232 and is connected to the inner end of the spring portion 1232c.

[0199] The dotted circle in FIG. 34 indicates the outermost rotation locus of the connecting portion 1232d. Let the radius of this rotation locus be r1. The connecting portion 1232d includes a portion where the distance from the rotation center is shorter than r1. That is, it includes a portion that rotates within the outermost rotation locus. Specifically, the connecting portion 1232d includes a portion where the distance from the rotation center of the mustache spring 1232 is r2 (<r1). Further, the connecting portion 1232d preferably includes a portion where the distance from the rotation center of the mustache spring 1232 is r3 (<r2). By adopting such a connecting portion 1232d having such a planar shape, a shrinkage allowance region M that allows the shrinkage of the spring portion 1232c is formed. As the shrinkage allowance region M is formed, the shrinkage range of the spring portion 1323c increases.

[0200] The step adjustment means 40 obtains a detection signal based on the operation of the permanently magnetized permanent magnet 41. If there is a member that magnetically affects the periphery of the permanent magnet 41, the detection accuracy may decrease. Therefore, it is preferable to adopt a material with little magnetic influence as the material of the members around the permanent magnet 41. For example, a resin material may be used as the material of the support member 33 and the mustache holder 34. Also, phosphor bronze or brass may be used as the material of the fixture for fixing the support member 33 to the floor board 10. Further, a resin material, aluminum, brass, or the like may be used as the material of the retaining ring 31.

[0201] Also, although not shown, the mechanical watch 1 may have an opening or a transparent portion on the dial or the back cover for visually recognizing the retaining ring 31 from the outside.

Explanation of Signs

[0202] 1 Mechanical watch, 2 Mainspring, 10 Floor board, 10a Positioning pin, 10b Opening, 1 1 Power spring, 122 Second wheel, 123 Third wheel, 124 Fourth wheel, 13 Pointer shaft, 131 Second hand, 20 Escapement mechanism, 21 Gang wheel, 22 Anchor, 221 Anchor spring , 222 Rod, 223 First arm, 223a In-claw, 224 Second arm, 224a Out pawls, 30 regulator, 31 balance wheel, 311 balance stem, 311c fitting, 312 swing seat, 312a impulse stone, 312b insertion hole, 312c positioning groove, 32 hairspring , 33 support member, 34 hair support, 35 positioning frame, 351 fitting portion, 352 annular Protrusion, 40 Speed ​​adjustment means, 41 Permanent magnet, 41h Through hole, 42 Soft magnetic core, 42 1 First magnetic part, 421a First end, 422 Second magnetic part, 422a Second end, 42 3 first welded portion, 424 second welded portion, 43 coil, 44 control circuit, 45 rotation detection circuit, 46 speed control pulse output circuit, 47 frequency divider circuit, 48 oscillation circuit, 50 rectifier circuit, 60 power supply circuit, 70 crystal oscillator, 80 damping circuit, 140 holding member, 141 bottom , 141a insertion hole, 141b positioning groove, 142 side wall portion, 330 bearing structure, 333 end stone, 334 end stone holding member, 334a notch, 334b ​​notch, n1 1,n12,n21,n22 notches.

Claims

1. A power source is used to drive the tenshin, a hairspring that elastically deforms to rotate the balance shaft in forward and reverse directions; and the forward and reverse rotational motion of the balance shaft includes a period in which the balance shaft rotates freely relative to the hairspring and a period in which the balance shaft transmits a rotational force to the hairspring and elastically deforms the hairspring; Speed ​​regulating mechanism.

2. the hairspring is not fixed to the balance shaft; The speed regulating mechanism according to claim 1 .

3. a contact portion that repeatedly comes into and out of contact with the hairspring in accordance with forward and reverse rotational motion of the balance shaft; The speed control mechanism according to claim 1 or 2.

4. the hairspring includes an elastically deformable spiral spring portion, an inner end portion through which the balance shaft is inserted, and a connecting portion that connects the spring portion and the inner end portion and forms a gap between the spring portion and the inner end portion that allows movement of the contact portion, The speed control mechanism according to claim 3.

5. The rotation angle of the balance shaft is at least 0° or more and less than 180°, and includes a period in which the contact portion is not in contact with the connection portion. The speed regulating mechanism according to claim 4.

6. The planar shape of the connection portion includes a portion that expands radially outward, a period during which the balance shaft rotates idly relative to the hairspring is determined according to the extent of expansion of the portion expanding radially outward; The speed regulating mechanism according to claim 4.

7. the planar shape of the connection portion includes a portion in which the distance from the rotation center of the hairspring to the radial end portion is shorter than the radius of the rotation locus of the outermost portion of the connection portion in the radial direction; The speed regulating mechanism according to claim 4.

8. The speed regulating mechanism according to claim 1 or 2; a permanent magnet that rotates in a forward and reverse direction in accordance with the forward and reverse rotation of the balance shaft; A coil and a soft magnetic core including: a first end provided so as to generate magnetic resistance between itself and the permanent magnet; and a second end provided on the opposite side of the first end across the permanent magnet so as to generate magnetic resistance between itself and the permanent magnet; a rate adjusting means for adjusting the rate based on a detected voltage generated in the coil due to the movement of the permanent magnet accompanying the forward and reverse movements of the balance shaft and a reference frequency of a reference signal source; A mechanical watch having a

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