Mechanical watch

Abstract

To efficiently take out electric power in a mechanical watch 1 performing rate adjustment by using electromagnetic means.SOLUTION: A mechanical watch has: a balance wheel; a balance spring; a permanent magnet 41; a soft magnetic core; a control circuit that performs rate adjustment on the basis of a counter electromotive force generated in a coil due to a motion of the permanent magnet 41 along with a normal direction motion and a reverse direction motion of the balance wheel, and a reference frequency of a reference signal source; a rectification circuit that rectifies a current generated in the coil due to a motion of the permanent magnet 41 along with the normal direction motion and the reverse direction motion of the balance wheel, and a power supply circuit that drives the control circuit on the basis of the current rectified by the rectification circuit. The permanent magnet 41 is arranged such that a magnetization direction is directed to a side of a first end 421a or a second end 422a, in a state where the balance spring is at a neutral position of its elastic deformation.SELECTED DRAWING: Figure 13A

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a mechanical timepiece that generates electricity based on the movement of a magnet attached to the axle (balance stem) and has a function for adjusting the rate by observing the period of rotation of the balance (for example, paragraphs 0072, 0073, Figure 27, etc. of Patent Document 1). Patent Document 2 also discloses a configuration in which electricity is generated using power obtained by full-wave rectification using a rectifier including four diodes (for example, Figure 13 of Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-38206 [Patent Document 2] Japanese Patent Application Publication No. 2019-113548 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, since the power generated by the movement of the magnet accompanying the movement of the balance is minute, some means is required to extract the power efficiently. However, when full-wave rectification is performed using a rectifier including multiple diodes, as in Patent Document 2, a voltage drop occurs according to the number of diodes, resulting in power loss.

[0005] The present invention has been made in view of the above-mentioned problems, and its object is to efficiently extract power from a mechanical timepiece that uses electromagnetic means to adjust the rate. [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 bipolar permanent magnet that rotates in forward and reverse directions in accordance with the forward and reverse rotation of the balance wheel; a coil; a soft magnetic core that includes a first end provided along the outer periphery of the permanent magnet and a second end provided along the outer periphery of the permanent magnet and positioned opposite the first end via the permanent magnet, and that forms a magnetic circuit together with the coil; and a balance spring that elastically deforms to rotate the balance wheel in forward and reverse directions in accordance with the forward and reverse rotation of the balance wheel. a control circuit that adjusts 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 wheel and a reference frequency of a reference signal source; a rectifier circuit that rectifies a current generated in the coil due to the movement of the permanent magnet accompanying the forward and reverse movements of the balance wheel; and a power supply circuit that drives the control circuit based on the current rectified by the rectifier circuit, wherein the permanent magnet is arranged so that its magnetization direction faces the first end or the second end when the hairspring is in a neutral position of its elastic deformation.

[0007] (2) In (1), the permanent magnet is arranged so that the magnetization direction is the same as the opposing direction of the first end and the second end when the hairspring is in a neutral position of its elastic deformation.

[0008] (3) A mechanical timepiece in (1) or (2), wherein the soft magnetic core includes a first separation part that separates the magnetic coupling between the first end and the second end, and a second separation part that separates the magnetic coupling between the first end and the second end and is arranged opposite the first separation part via the permanent magnet, and the permanent magnet is arranged so that its magnetization direction is perpendicular to the opposing direction of the first separation part and the second separation part when the hairspring is in the neutral position.

[0009] (4) In (1) or (2), the soft magnetic core includes a first separation portion that separates the magnetic coupling between the first end and the second end, and a second separation portion that separates the magnetic coupling between the first end and the second end and is arranged opposite the first separation portion via the permanent magnet, and the permanent magnet includes an N-pole portion and an S-pole portion, and is arranged so that when the hairspring is in the neutral position, the boundary between the N-pole portion and the S-pole portion overlaps with an imaginary band-shaped area connecting the first separation portion and the second separation portion.

[0010] (5) A mechanical timepiece according to any one of (1) to (4), wherein the balance wheel is in a power supply position where power is supplied from the power source when the hairspring is in the neutral position.

[0011] (6) In (5), the permanent magnet is positioned so that the detected voltage detected during the period from the power supply position until the permanent magnet rotates 180° in the forward or reverse direction has the same polarity.

[0012] (7) A mechanical timepiece according to any one of (1) to (6), comprising a rotation detection circuit that detects a detection signal based on the detection voltage, and a speed regulating pulse output circuit that outputs a speed regulating pulse that controls the movement of the balance wheel, wherein the control circuit controls the speed regulating pulse output circuit based on the detection timing of the detection signal and the output timing of a reference signal based on the reference frequency.

[0013] (8) In (7), the regulating pulse output circuit outputs the regulating pulse to either the first terminal or the second terminal of the coil when the detection timing of the detection signal is earlier than the output timing of the reference signal, and outputs the regulating pulse to the other of the first terminal or the second terminal when the detection timing of the detection signal is later than the output timing of the reference signal.

[0014] (9) In the mechanical timepiece of (7) or (8), the speed control pulse output circuit is configured to be able to output a plurality of speed control pulses having different output periods.

[0015] (10) The mechanical timepiece according to any one of (7) to (9), wherein the speed control pulse output circuit is configured to be able to output a plurality of speed control pulses having different duty ratios.

[0016] (11) In the mechanical timepiece of (9) or (10), the speed control pulse output circuit outputs the speed control pulse according to the amount of deviation of the detection timing of the detection signal from the output timing of the reference signal.

[0017] (12) In (11), a mechanical watch has a storage unit that stores the amount of deviation of the detection timing of the detection signal from the output timing of the reference signal, and the speed control pulse output circuit outputs the speed control pulse according to the amount of deviation stored in the storage unit.

[0018] (13) A mechanical timepiece according to any one of (1) to (12), further comprising a deceleration means that is provided in a predetermined direction relative to the rotation axis of the balance wheel and that acts on the balance wheel during each of the forward and reverse motions of the forward and reverse rotational motion of the balance wheel, thereby slowing down the balance wheel, and the balance wheel includes an acted portion that is formed at a part in the circumferential direction and that is acted on by the deceleration means.

[0019] (14) In the mechanical timepiece of (13), the control circuit adjusts the rate based on the reference frequency and the detected voltage generated in the coil by the movement of the permanent magnet before the acted part reaches the position of the deceleration means in the forward and reverse rotational movements of the balance wheel.

[0020] (15) In the mechanical timepiece of (13) or (14), the control circuit adjusts the rate during the period after the acted part reaches the position of the deceleration means in the forward and reverse rotational movements of the balance wheel.

[0021] (16) A mechanical timepiece according to any one of (13) to (15), wherein the control circuit is driven by the supply of a back electromotive force generated in the coil by the movement of the permanent magnet before the acted part reaches the position of the deceleration means in the forward and reverse rotational movements of the balance wheel.

[0022] (17) A mechanical timepiece according to any one of (1) to (16), wherein the rectifier circuit includes one diode.

[0023] (18) A mechanical watch according to any one of (1) to (17), wherein the balance spring is made of resin.

[0024] (19) A mechanical timepiece according to any one of (1) to (18), wherein the first end and the second end are formed with at least one pair of opposing notches that reduce the holding torque of the permanent magnet.

[0025] (20) A mechanical timepiece according to any one of (1) to (19), wherein the hairspring is provided so as to cause the balance wheel to make one reciprocating motion in two seconds. [Effects of the Invention]

[0026] According to the above aspects (1) to (20) of the present invention, in a mechanical timepiece that uses electromagnetic means to adjust the rate, it is possible to extract power efficiently. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 2 is a perspective view showing the base plate and the components assembled thereto according to the present embodiment. [Figure 2] FIG. 2 is a perspective view showing a power transmission mechanism and its surroundings in the embodiment. [Figure 3] FIG. 2 is an exploded perspective view showing the speed regulating mechanism and its peripheral members disassembled from the main plate in the present embodiment. [Figure 4]2 is a diagram showing a cross section of a support member and a soft magnetic core of the present embodiment, and the surrounding area thereof. FIG. [Figure 5] 2A and 2B are a plan view showing the soft magnetic core and its periphery according to the present embodiment, and an enlarged plan view showing a part of the soft magnetic core and its periphery in an enlarged manner. [Figure 6] FIG. 2 is a plan view showing the speed regulating mechanism and its periphery according to the present embodiment. [Figure 7] 4 is a graph illustrating the holding torque of a permanent magnet in the present embodiment. [Figure 8] 1 is a block diagram showing the overall configuration of a mechanical timepiece according to an embodiment of the present invention. [Figure 9] FIG. 2 is an exploded perspective view showing the air resistance member disassembled from the base plate. [Figure 10] FIG. 2 is a perspective view showing the operation of the balance wheel of the present embodiment. [Figure 11A] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11B] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11C] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11D] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11E] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11F] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11G] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11H] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11I] FIG. 10 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11J] FIG. 10 is a perspective view showing a balance wheel and an elastic member in a modified example of the embodiment. [Figure 11K]FIG. 10 is a perspective view showing another example of a balance wheel as viewed from the side where the hairspring is provided. [Figure 11L] FIG. 11C is a perspective view showing the balance wheel shown in FIG. 11K as viewed from the side opposite to the side where the hairspring is provided. [Figure 11M] FIG. 2 is a plan view showing a state in which the balance spring is in a neutral position of its elastic deformation. [Figure 11N] 10 is a plan view showing a state in which the balance spring is elastically deformed in the expanding direction from the neutral position. FIG. [Figure 11O] 10 is a plan view showing a state in which the balance spring is elastically deformed in the contracting direction from the neutral position. FIG. [Figure 12] 5A and 5B are diagrams illustrating the relationship between the operation of the balance wheel and the back electromotive force generated in the coil in this embodiment. [Figure 13A] FIG. 10 is a diagram showing the back electromotive force detected by the coil in the arrangement of the permanent magnets of the present embodiment. [Figure 13B] FIG. 10 is a diagram showing the back electromotive force detected by the coil in the arrangement of the permanent magnets in Comparative Example 1. [Figure 13C] FIG. 10 is a diagram showing the back electromotive force detected by the coil in the arrangement of the permanent magnets in Comparative Example 2. [Figure 14A] FIG. 2 is a circuit diagram showing an example of a circuit according to the present embodiment. [Figure 14B] FIG. 10 is a circuit diagram showing another example of the circuit according to the present embodiment. [Figure 15A] 4A and 4B are diagrams illustrating control of the movement of the permanent magnet by a speed control pulse in this embodiment. [Figure 15B] 4A and 4B are diagrams illustrating control of the movement of the permanent magnet by a speed control pulse in this embodiment. [Figure 16] 4 is a flowchart showing an example of rate adjustment control according to the present embodiment. [Figure 17] 10 is a timing chart showing an example in which a detection signal is detected within an output period of a reference signal. [Figure 18] 10 is a timing chart showing an example in which the detection timing of the detection signal is earlier than the output period of the reference signal. [Figure 19]10 is a timing chart showing an example in which the timing at which the detection signal is detected is later than the output period of the reference signal. [Figure 20] 10 is a flowchart showing a first modified example of rate adjustment control. [Figure 21] 10 is a timing chart showing a detection signal and a reference signal in a first modified example of rate adjustment control. [Figure 22] 10 is a flowchart showing a second modified example of rate adjustment control. [Figure 23] 10 is a timing chart showing a detection signal and a reference signal in a second modified example of rate adjustment control. [Figure 24] FIG. 10 is a diagram showing an example of a speed control pulse. [Figure 25] 4 is a timing chart showing an example of rate adjustment control when the power supply circuit starts to start from a stopped state. [Figure 26] 4 is a timing chart showing an example of rate adjustment control taking into account the influence of disturbances. [Figure 27] 10 is a flowchart showing an example of rate adjustment control taking into consideration the influence of disturbances. [Figure 28] 21 is a flowchart showing rate adjustment control in which the influence of disturbance is taken into consideration in the first modified example of the rate adjustment control shown in FIG. 20. [Figure 29] 10 is a timing chart showing an example of rate adjustment control when detection of a detection signal fails repeatedly. [Figure 30] 10 is a timing chart showing an example of rate adjustment control when detection of a detection signal fails repeatedly. [Figure 31] 10 is a flowchart showing an example of rate adjustment control assuming that detection of a detection signal fails continuously. [Figure 32] 10 is a timing chart showing an example of output timing of a reference signal. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, an embodiment of the present invention (hereinafter referred to as the present embodiment) will be described in detail with reference to the drawings.

[0029] [Overall configuration overview] First, an overview of the overall configuration of a mechanical timepiece 1 according to this embodiment will be explained with reference to Figs. 1 to 8. Fig. 1 is a perspective view showing the main plate of this embodiment and the various components incorporated therein. Fig. 2 is a perspective view showing the power transmission mechanism and its surroundings in this embodiment. Fig. 3 is an exploded perspective view showing the speed regulating mechanism and its surrounding components in this embodiment disassembled from the main plate. Figs. 1 to 3 show the mechanical timepiece 1 as seen from the back side. The back side is the side in the thickness direction of the mechanical timepiece 1 where the back cover of the exterior case is located.

[0030] FIG. 4 is a diagram showing a cross section of the support member and soft magnetic core of this embodiment, and their surroundings. FIG. 5 is a plan view showing the soft magnetic core of this embodiment and its surroundings, and an enlarged plan view showing a portion of it. FIG. 6 is a plan view showing the speed regulating mechanism of this embodiment and its surroundings. FIG. 7 is a graph explaining the holding torque of the permanent magnet of this embodiment. FIG. 8 is a block diagram showing the overall configuration of the mechanical timepiece of this embodiment. Note that FIG. 5 shows the mechanical timepiece 1 as seen from the back side, and FIG. 6 shows the mechanical timepiece 1 as seen from the front side. Note that the front side is the side in the thickness direction of the mechanical timepiece 1 from which the user can view the hands and dial.

[0031] In this embodiment, the counterclockwise direction of the balance wheel 31 and the permanent magnet 41 in each of the figures except for FIG. 6 is defined as the forward direction, and the clockwise direction is defined as the reverse direction.

[0032] The mechanical timepiece 1 is a timepiece that uses a power spring 11 as its power source, and controls the movement of the power spring 11 with an escapement mechanism 20 and a speed regulator mechanism 30, while also driving the hands. The mechanical timepiece 1 is configured by housing a main plate 10, into which the mechanisms that drive the hands are incorporated, in an exterior case. Note that in this embodiment, the exterior case is not shown. The crown, which is located on the side of the exterior case, is also not shown. The crown is attached to the end of the winding stem 2 shown in FIG. 1.

[0033] [Overall configuration: Drive mechanism configuration] An overview of the drive mechanism of the mechanical timepiece 1 will now be described. In this embodiment, the mechanism including the power spring 11, which is the power source, the train wheel 12, and the hand shaft 13 will be 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 an example, and is not limited to this, and may include gears and the like other than those shown.

[0034] The power spring 11 is made of a metal strip and is housed in a barrel 110 with multiple teeth formed on its outer periphery. The barrel 110 is disk-shaped and has a cavity formed therein to house the power spring 11. The inner end of the power spring 11 is fixed to a barrel stem (not shown), which is a rotation axis 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. As the winding stem 2 rotates, the power spring 11 is wound up. 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.

[0035] The wheel train 12 includes at least a center wheel & pinion 122, a third wheel & pinion 123, and a fourth wheel & pinion 124. The center wheel & pinion 122 includes a pinion that meshes with multiple teeth formed on the barrel 110, which functions as the first wheel, a rotation axis, and multiple teeth, and transmits the rotation of the barrel 110 to the third wheel & pinion 123. The rotation axis of the center wheel & pinion 122 is the pointer stem of the minute hand (not shown). The third wheel & pinion 123 includes a pinion that meshes with multiple teeth of the center wheel & pinion 122, a rotation axis, and multiple teeth, and transmits the rotation of the center wheel & pinion 122 to the fourth wheel & pinion 124. The fourth wheel & pinion 124 includes a pinion that meshes with multiple teeth of the third wheel & pinion 123, a rotation axis, and multiple teeth, and transmits the rotation of the third wheel & pinion 123 to the escapement mechanism 20. As shown in FIG. 2, the rotation axis of the fourth wheel & pinion 124 is the pointer stem 13 of the second hand 131.

[0036] [Overview of the overall configuration: Overview of the configuration of the escapement mechanism 20 and the speed regulating 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 the wheel train 12. The escapement mechanism 20 is configured to include an escape wheel 21 and an anchor 22. The regulating mechanism 30 is configured to include a balance wheel 31 and a hairspring 32. The regulating mechanism 30 is sometimes called a balance.

[0037] The escape wheel 21 is a component that meshes with the pallet fork 22 to receive the rhythm of the regulating mechanism 30 from the pallet fork 22 and converts it into regular reciprocating 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 FIG. 2 , the multiple teeth of the escape wheel 21 are formed at wider circumferential intervals than the teeth of each gear of the train wheel 12.

[0038] The pallet fork 22 rotates forward and backward around the pallet fork arbor 221 shown in Figure 5 as its rotation axis. The pallet fork 22 extends from the pallet fork arbor 221 toward the center of the balance wheel 31 (balance arbor 311) and has a rod portion 222 that strikes an impulse jewel 315 (see Figure 6) that rotates together with the balance arbor 311. The impulse jewel 315 is fixed to a disk-shaped portion of the balance arbor 311 that has a predetermined width in the radial direction. Figure 6 shows the balance wheel 31 rotated by θ from a rotation angle of 0°, and the position of the impulse jewel 315 in that state.

[0039] Furthermore, the pallet fork 22 has a first arm 223 to which is attached an indented pawl 223a that strikes against multiple teeth of the escape wheel and pinion 21, and a second arm 224 to which is attached an extending pawl 224a that extends in the opposite direction from the first arm 223 and strikes against multiple teeth of the escape wheel and pinion 21. The indented pawl 223a and the extending pawl 224a may be made of a stone such as sapphire, for example.

[0040] The balance wheel 31 rotates forward and backward around the balance arbour 311 by power transmitted by the wheel train 12. In the following description, the forward movement of the forward and reverse rotational movements may be referred to as "forward rotation" and the reverse movement as "reverse rotation." The configuration of the balance wheel 31 will be described in detail later. The balance arbour 311 is supported by a support member 33 shown in Figures 3 and 4.

[0041] The hairspring 32 expands and contracts (elastically deforms) so as to rotate the balance wheel 31 forward and backward. The hairspring 32 is spiral-shaped, and its inner end is fixed to the balance axle 311, and its outer end is fixed to a hairspring 34. The hairspring 34 is fixed to the main plate 10 together with a support member 33. As shown in FIG. 3 , the hairspring 34 is sandwiched between the support member 33 and a frame member 35.

[0042] The escape wheel 21 rotates in conjunction with the rotation of the second wheel & pinion 124. As the escape wheel 21 rotates, it collides with the pallet insert 223a of the pallet fork 22, causing the pallet fork 22 to rotate around the pallet fork arbor 221. The rotating shaft 222 of the pallet fork 22 collides with the impulse jewel 315 fixed to the balance arbor 311, causing the balance wheel 31 to rotate. As the balance wheel 31 rotates, the pallet insert 224a of the pallet fork 22 collides with the escape wheel 21, stopping the escape wheel 21. When the balance wheel 31 rotates in the opposite direction due to the restoring force of the hairspring 32, the pallet insert 223a of the pallet fork 22 is released, causing the escape wheel 21 to rotate again. As will be described later, the balance wheel 31 is designed to perform one cycle of movement in two seconds, so the escape wheel 21 performs one step of movement per second.

[0043] As described above, the speed regulating mechanism 30 causes the balance wheel 31 to repeatedly rotate forward and backward (reciprocating) at a constant cycle by the expansion and contraction motion of the hairspring 32. The escapement mechanism 20 continuously applies a force to the balance wheel 31 for reciprocating motion. This configuration and operation drives the hands such as the second hand 131.

[0044] [Overview of Overall Configuration: Configuration of Rate Adjusting Means 40] Next, we will explain the configuration of the rate adjustment means 40. The mechanical timepiece 1 according to this embodiment includes the rate adjustment means 40 in addition to the drive mechanism, escapement mechanism 20, and speed regulation mechanism 30.

[0045] The rate adjustment means 40 is configured to include a permanent magnet 41, a soft magnetic core 42 (sometimes called a stator), a coil 43, and various circuits (see FIG. 8). 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 the reference frequency of a quartz oscillator 70 (see FIG. 8), which serves as a reference signal source. Note that in this embodiment, the quartz oscillator 70 is used as the reference signal source to achieve high frequency accuracy, but the present invention is not limited to this. For example, a CR oscillator composed of a capacitor and a resistor may also be used.

[0046] Although not shown, 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 portion of the inner frame in the circumferential direction, and the coil 43 may be arranged within the notch.

[0047] 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 and an S pole portion 412.

[0048] The permanent magnet 41 is attached to the balance stem 311, which is the rotation axis of the balance wheel 31 (see FIG. 10 described later), and is provided so as to rotate in both directions in accordance with the forward and reverse rotation of the balance wheel 31 (balance stem 311). In other words, the permanent magnet 41 rotates in both directions together with the balance wheel 31 so that its rotation angle is the same as the rotation angle of the balance wheel 31. The permanent magnet 41 is preferably fixed to the balance stem 311 by press-fitting, adhesive bonding, or the like.

[0049] The permanent magnets 41 are preferably isotropic magnets whose easy axes of magnetization are oriented in random directions. The permanent magnets 41 are preferably magnetized by applying a magnetic field using a Helmholtz coil or the like while attached to the balance shaft 311. By employing such a magnetization method, the magnetization direction of the permanent magnets 41 can be accurately aligned.

[0050] 5, the soft magnetic core 42 is made of a soft magnetic material and has a first magnetic portion 421 including a first end portion 421a provided along the outer periphery of the permanent magnet 41, and a second magnetic portion 422 including a second end portion 422a provided along the outer periphery of the permanent magnet 41, and forms a magnetic circuit together with the coil 43. The first end portion 421a and the second end portion 422a both have a semicircular arc-shaped inner circumferential surface and are arranged opposite each other with the permanent magnet 41 interposed therebetween.

[0051] In this embodiment, when the hairspring 32 is in a neutral position of elastic deformation, the N-pole portion 411 of the permanent magnet 41 is disposed on the second magnetic portion 422 side, and the S-pole portion 412 is disposed on the first magnetic portion 421 side (see the enlarged view in FIG. 5). Note that the arrangement of the N-pole portion 411 and the S-pole portion 412 may be reversed, but in that case, the winding direction of the coil 43 needs to be reversed from that of this embodiment.

[0052] 3 and 4, the soft magnetic core 42 is fixed to the support member 33 by a pipe 33a and a screw 33b, which are fasteners. With this configuration, the soft magnetic core 42 is attached to the base plate 10 together with the support member 33. The support member 33 and the soft magnetic core 42 are positioned by a positioning pin 10a provided on the base plate 10 and a frame member 35.

[0053] As shown in FIG. 4 , the frame member 35 has an annular protrusion 35a. The protrusion 35a is fitted to the inner circumferential surfaces of the first end 421a and the second end 422a of the soft magnetic core 42. The soft magnetic core 42 is positioned at two locations: the frame member 35 and the positioning pin 10a. This configuration allows the soft magnetic core 42 to be assembled to the base plate 10 with high positioning accuracy. As a result, the positioning accuracy of the soft magnetic core 42 relative to the permanent magnet 41 can be improved. The soft magnetic core 42 is made of a magnetic material, and its magnetic properties may deteriorate if subjected to strong stress. For example, if the soft magnetic core 42 is directly fastened to the base plate 10 with screws or the like, the magnetic properties may deteriorate. Therefore, in this embodiment, the positioning pin 10a and the frame member 35 are fitted together with a clearance fit, and the soft magnetic core 42 is fixed to the support member 33 with the pipe 33a and the screw 33b, thereby achieving both positioning and fixation of the soft magnetic core 42. By adopting such a configuration, it is possible to improve the positioning accuracy of the soft magnetic core 42 without deteriorating the magnetic characteristics of the soft magnetic core 42. Furthermore, in this embodiment, the soft magnetic core 42 is arranged to be fixed to the support member 33, but it is also possible to arrange the permanent magnet 41 corresponding to the soft magnetic core 42 between the balance wheel 31 and the main plate 10, and directly fasten the soft magnetic core 42 to the main plate 10 with a screw or the like.

[0054] Of the components assembled to the main plate 10, those components such as the support member 33, balance holder 34, frame member 35, balance spring 32, and balance wheel 31, which are located near the permanent magnet 41 except for the soft magnetic core 42, are preferably made of non-magnetic materials so as not to affect the forward and reverse rotational movement of the regulating mechanism 30 or the back electromotive force generated by the coil 43 described below.

[0055] 5, the soft magnetic core 42 includes a first welded portion 423 which is a first separator that separates the magnetic coupling between the first end 421a and the second end 422a, and a second welded portion 424 which is a second separator that separates the magnetic coupling between the first end 421a and the second end 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 421a and the second end 422a.

[0056] The permanent magnet 41 is in a magnetically balanced position when its magnetization direction is perpendicular to the opposing direction of the first welded portion 423 and the second welded portion 424. In this embodiment, the magnetically balanced position of the permanent magnet 41 is defined as a rotation angle of 0°. In this position, the holding torque of the permanent magnet 41 is approximately 0. Note that the opposing direction of the first welded portion 423 and the second welded portion 424 is the direction in which a straight line connecting the first welded portion 423 and the second welded portion 424 extends, as shown in FIG. 5 .

[0057] When the rotation angle of the permanent magnet 41 is shifted 90° in the positive direction from 0°, the magnetization direction of the permanent magnet 41 is the same as the opposing direction of the first welded portion 423 and the second welded portion 424. At this position, the holding torque of the permanent magnet 41 is approximately 0. The dashed bold line graph in FIG. 7 indicates the holding torque of the permanent magnet 41 resulting from the formation of the first welded portion 423 and the second welded portion 424.

[0058] As shown in FIG. 5, in this embodiment, notches are formed on the inner circumferential surfaces of the first end 421a and the second end 422a of the soft magnetic core 42. Specifically, notch n11 and notch n12 are formed in the first end 421a. Furthermore, notch n21 is formed in the second end 422a so as to face notch n11 across the permanent magnet 41, and notch n22 is formed so as to face notch n12 across the permanent magnet 41. By forming the notches in this manner, the magnetic influence that the soft magnetic core 42 has on the permanent magnet 41 is reduced. Therefore, the holding torque of the permanent magnet 41 can be reduced.

[0059] One dashed line graph in Figure 7 shows the holding torque of the permanent magnet 41 due to the formation of notches n11 and n21 arranged opposite each other, and the other dashed line graph shows the holding torque of the permanent magnet 41 due to the formation of notches n12 and n22 arranged opposite each other.

[0060] The solid line graph in FIG. 7 shows the composite holding torque obtained by combining the three dashed line graphs. That is, the solid line graph in FIG. 7 shows the holding torque of the permanent magnet 41 resulting from the formation of the first welded portion 423, the second welded portion 424, and the notches n11, n12, n21, and n22 on the soft magnetic core 42. As shown in FIG. 7 , in the configuration of this embodiment, the holding torques shown by the dashed line graphs cancel each other out at each rotation angle, and the composite holding torque of the permanent magnet 41 is close to zero at all rotation angles. Therefore, even when using a hairspring 32 made of a material with a low Young's modulus, as described below, the permanent magnet 41 can be smoothly rotated. Note that the number, arrangement, and shape of the notches shown in FIG. 5 are merely examples and are not limited thereto. Preferably, at least one pair of opposing notches that reduce the holding torque of the permanent magnet 41 is formed on the first end 421a and the second end 422a.

[0061] [Overall configuration overview: Rate adjustment overview] As shown in FIG. 8, the mechanical timepiece 1 includes a rectifier circuit 50, a power supply circuit 60, and a quartz oscillator 70 in addition to the power spring 11, wheel train 12, escapement mechanism 20, speed regulating mechanism 30, and rate adjustment means 40 described above. Also, as shown in FIG. 8, the rate adjustment means 40 includes a control circuit 44, a rotation detection circuit 45, a speed regulating pulse output circuit 46, a frequency divider circuit 47, and an oscillation circuit 48 in addition to the permanent magnet 41, soft magnetic core 42, and coil 43 described above. Note that the configuration of the rate adjustment means 40 shown in FIG. 8 is just one example. The rate adjustment means 40 does not need to have each circuit shown in FIG. 8 independently, and it is sufficient if it is capable of realizing each of the functions described below.

[0062] The control circuit 44 is a circuit that controls the operation of each circuit included in the rate adjusting means 40.

[0063] The oscillator 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 oscillator 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 to this, and the reference signal OS may also be output every 2000 ms or 3000 ms. In other words, the reference signal OS may be output every second. Furthermore, this is not limited to this, and the reference signal OS may be output every second.

[0064] The rotation detection circuit 45 detects a detection signal based on the voltage waveform generated in the coil 43 due to the movement of the permanent magnet 41. 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 approximately 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).

[0065] The speed control pulse is output by energizing the coil 43. Therefore, when the cycle at which the detection signal is detected is faster than the reference signal, the speed control pulse output circuit 46 energizes the coil 43 so that torque acts in a direction that slows down the movement of the permanent magnet 41, and when the cycle at which the detection signal is detected is slower than the reference signal, the speed control circuit 46 energizes the coil 43 so that torque acts in a direction that speeds up the movement of the permanent magnet 41. Details of the rate adjustment control, including the output timing of the speed control pulse, will be described later.

[0066] [Overview of overall configuration: Speed ​​control mechanism 30 as a generator] The mechanical timepiece 1 also has a power generation function that uses the principle of electromagnetic induction. In this embodiment, the regulating mechanism 30 functions as part of the generator. Specifically, the permanent magnet 41 rotates forward and backward as the balance wheel 31 rotates forward and backward, 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 using this operating principle is used to start the power supply circuit 60. When the power supply circuit 60 is started, the control circuit 44 included in the rate adjustment means 40 can be driven. By adopting this configuration, in this embodiment, the control circuit 44 can be driven without providing a separate power source such as a battery.

[0067] Rectifier circuit 50 rectifies the current generated in coil 43 by the movement of permanent magnet 41 that accompanies the forward and reverse rotational movements of the balance wheel of speed regulating mechanism 30. Power supply circuit 60 is a circuit that includes, for example, a capacitor, and stores power for driving control circuit 44 based on the current rectified by rectifier circuit 50.

[0068] [About slowing down the balance wheel 31] In the mechanical timepiece 1, the faster the balance wheel 31 moves, that is, the faster the operating cycle of the balance wheel 31, the more easily the mechanisms that transmit power (for example, the escape wheel 21 and the anchor 22) wear, resulting in a decrease in durability. On the other hand, because the amount of current generated in the coil 43 is proportional to the angular velocity of the permanent magnet 41, if the balance wheel 31 moves slowly, the amount of power generated necessary to drive the control circuit 44 cannot be obtained.

[0069] Therefore, in this embodiment, a configuration is adopted that can slow down the movement of the balance wheel 31 and ensure the amount of power generation.

[0070] FIG. 10 is a perspective view showing the operation of the balance wheel of this embodiment. FIG. 10 also shows the balance wheel 31, the anchor 22, the permanent magnet 41, and the air resistance member 15 (described later). Reference numerals are omitted in FIG. 10 except for the diagram showing the state at a rotation angle of 0°. FIG. 12 is a diagram illustrating the relationship between the operation of the balance wheel and the back electromotive force generated in the coil in this embodiment. In the upper graph of FIG. 12, the vertical axis represents the angular velocity [rad / s] of the balance wheel 31, and the horizontal axis represents the measurement time [s]. In the middle graph of FIG. 12, the vertical axis represents the rotation angle [deg] of the balance wheel 31, and the horizontal axis represents the measurement time [s]. In the lower graph of FIG. 12, the vertical axis represents the back electromotive force [V] generated in the coil 43, and the horizontal axis represents the measurement time [s]. Each graph in FIG. 12 shows an example in which the movement of the balance wheel 31 (permanent magnet 41) was measured for four seconds.

[0071] In this embodiment, the balance wheel 31 is designed to make one reciprocating motion every two seconds. To achieve this, a resin material with a low Young's modulus is used as the material for the hairspring 32. This makes it possible to achieve a slower oscillation speed for the balance wheel 31 than if it were made of a metal material. If an attempt were made to achieve a slower oscillation speed with a metal hairspring, the cross-sectional area of ​​the hairspring 32 would have to be reduced to a level that makes it difficult to process, or the hairspring length would have to be increased to a level that makes it difficult to handle.

[0072] In this embodiment, a resin with a Young's modulus of approximately 5 GPa is used as the material for the hairspring 32. Specifically, polyester is used as the material for the hairspring 32. The hairspring 32 made of a resin material may be manufactured, for example, by laser processing. The Young's modulus of a typical metal hairspring is approximately 200 GPa. The Young's modulus shown here is an example, and the Young's modulus of the hairspring 32 is preferably 20 GPa or less. In other words, the Young's modulus of the hairspring 32 is preferably 1 / 10 or less of the Young's modulus of a metal hairspring. More preferably, the Young's modulus of the hairspring 32 is 10 GPa or less. In other words, the Young's modulus of the hairspring 32 is preferably 1 / 20 or less of the Young's modulus of a metal hairspring. As long as the Young's modulus is 20 GPa or less, the hairspring 32 may be made of a material such as paper or wood. The shape of the hairspring 32 will be described in detail later with reference to FIGS. 11M to 11O.

[0073] In this embodiment, the rotation angle [deg] of the balance wheel 31 and the permanent magnet 41 when the hairspring 32 is in a neutral position for elastic deformation is set to 0°. The neutral position for elastic deformation of the hairspring 32 is, in other words, the position where the hairspring 32 is at its natural length. Power is supplied from the power spring 11 to the balance wheel 31 when the hairspring 32 is in a neutral position for elastic deformation. That is, the balance wheel 31 and the permanent magnet 41 are in a power supply position where power is supplied from the power spring 11 when the rotation angle is 0°. As described above, in this embodiment, the permanent magnet 41 is in a magnetically balanced position when the rotation angle is 0°.

[0074] Furthermore, in this embodiment, the balance wheel 31 is designed to drive within a rotation angle range of 340° to -340°. Therefore, the permanent magnet 41 also drives within a rotation angle range of 340° to -340°. However, this is just an example, and the movement range of the balance wheel 31 should preferably be greater than or equal to a rotation angle range of 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.

[0075] 10 shows the balance wheel 31 rotating in the positive direction from a rotation angle of 0° at intervals of 45° or 90°. Note that Fig. 10 only shows the balance wheel 31 at positive angles (0° to 340°), and does not show the balance wheel 31 at negative angles.

[0076] [On slowing down the balance wheel 31: Air resistance component 15] Furthermore, in this embodiment, the air resistance member 15, which is the speed reducing means, is attached to the main plate 10, and a configuration is adopted in which an acted-on portion 313 that receives air resistance from the air resistance member 15 is formed on a part of the circumferential direction of the balance wheel 31. Figure 9 is an exploded perspective view showing the air resistance member disassembled from the main plate.

[0077] The balance wheel 31 includes a circular part 312 that rotates forward and backward around a balance arbour 311, and an acted upon part 313 that protrudes radially from a part of the circumference of the circular part 312. In this embodiment, the acted upon part 313 is the part of the balance wheel 31 that has the longest radial length. In this embodiment, the acted upon part 313 has a fan-like shape, as shown in FIG. 10 .

[0078] The air resistance member 15 has resistance walls that form an air resistance area AR that generates air resistance. Specifically, the air resistance member 15 includes a first wall portion 151 that faces one surface of the acted upon portion 313 of the balance wheel 31, a second wall portion 152 that faces the other surface of the acted upon portion 313 of the balance wheel 31, and a third wall portion 153 that connects the first wall portion 151 and the second wall portion 152, and these wall portions form the air resistance area AR. The air resistance member 15 also has a base portion 154 that is integral with the first wall portion 151, the second wall portion 152, and the third wall portion 153 and is fixed to the main plate 10.

[0079] The air resistance member 15 is fixed to the main plate 10. In this embodiment, as shown in FIG. 9 , an opening 10b is formed in a portion of the main plate 10, the air resistance member 15 is fitted into the opening 10b, and a base 154 is fixed to the main plate 10 with a fastener such as a bolt. The air resistance member 15 is preferably fitted into the opening 10b from the side of the main plate 10 opposite the side where the drive mechanism, escapement mechanism 20, speed regulating mechanism 30, etc. are installed. In other words, the base 154 is preferably fixed to the surface of the main plate 10 opposite the side where the drive mechanism, escapement mechanism 20, speed regulating mechanism 30, etc. are installed. Note that FIG. 9 shows an example in which the opening 10b is formed in a portion of the main plate 10, but this is not limiting, and any other hole that penetrates from one side of the main plate 10 to the other may be used. For example, the main plate 10 may have a notch into which the air resistance member 15 is fitted, instead of the opening 10b.

[0080] In this embodiment, the air resistance member 15 is provided in a predetermined direction relative to the balance arbour 311, and is arranged so that the acted-on part 313 is located within the air resistance area AR when the rotation angle of the balance wheel 31 is between 135° and 225° (intermediate periods in the forward and reverse motions). That is, the acted-on part 313 of the balance wheel 31 experiences air resistance when the rotation angle of the balance wheel 31 is between 135° and 225°, causing a decrease in angular velocity. Similarly, although not shown, the acted-on part 313 of the balance wheel 31 experiences air resistance when the rotation angle of the balance wheel 31 is between -135° and -225° (intermediate periods in the forward and reverse motions), causing a decrease in angular velocity.

[0081] The rotational speed of the balance wheel 31 passing through the air resistance area AR decreases because the escape route for the air is blocked by the first wall portion 151, the second wall portion 152, and the third wall portion 153, causing the air to stagnate in the air resistance area AR and hindering the movement of the balance wheel 31.

[0082] As shown in the upper and middle graphs of Figure 12 at timings before the measurement time reaches 2.0 seconds, the angular velocity of the balance wheel 31 rises sharply from the position where the balance wheel 31 has a rotation angle of 0°, and reaches a peak at the measurement time of 2.0 seconds. This is because the balance wheel 31 receives power from the power spring 11 when the balance wheel 31 has a rotation angle of 0°.

[0083] The balance wheel 31 rotates in the forward direction from a rotation angle of 0°, and its angular velocity gradually decreases until it reaches 0 at a rotation angle of 340°, which is the halfway point between the forward and reverse rotational motion. Thereafter, the balance wheel 31 rotates in the reverse direction from the rotation angle of 340° in accordance with the elastic deformation of the balance spring 32.

[0084] As described above, the balance wheel 31 experiences air resistance from the air resistance member 15 when the rotation angle is between 135° and 225°, and therefore the angular velocity during this period decreases. Therefore, as shown in the middle graph of Fig. 12, the change in the rotation angle of the balance wheel 31 becomes gentle as it rotates backward from a rotation angle of 340° to a rotation angle of 0°.

[0085] Then, the balance wheel 31 returns to the position of rotation angle 0°, and receives power from the power spring 11, causing its angular velocity in the reverse direction to rise sharply and reach a peak. The angular velocity of the balance wheel 31 in the reverse rotation gradually decreases, and becomes 0 at a rotation angle of −340° (measurement time 3.0 seconds). Thereafter, the balance wheel 31 rotates in the forward direction from the rotation angle position of −340° in accordance with the elastic deformation of the hairspring 32.

[0086] Here, because the balance wheel 31 includes an acted-on part 313 that protrudes in the radial direction, the center of gravity of the balance wheel 31 is closer to the acted-on part 313 than to the balance arbour 311 (center of rotation). A configuration in which the center of gravity is shifted from the balance arbour 311, which is located at the center of the balance wheel 31, would result in unstable rotation of the balance wheel 31. Therefore, in this embodiment, an opening 312h is formed in part of the circular part 312 so that the center of gravity of the balance wheel 31 coincides with or approaches the balance arbour 311 (center position). As shown in FIG. 10 , the opening 312h is formed adjacent to the acted-on part 313 in the circumferential direction. By adopting such a configuration, the rotation of the balance wheel 31 is less likely to become unstable. In particular, even if the attitude of the mechanical timepiece 1 is displaced, the balance wheel 31 can be rotated stably.

[0087] In this embodiment, the air resistance member 15 is arranged so that the acted-on portion 313 is located within the air resistance region AR when the rotation angle of the balance wheel 31 is between 135° and 225°. The air resistance region AR is also arranged so that its center position 15C in the circumferential direction (see FIG. 6) overlaps with the positions of 180° and −180° of the balance wheel 31 in the rotation direction of the balance wheel 31. This makes the air resistance experienced by the acted-on portion 313 symmetrical when the balance wheel 31 rotates in the forward direction and when it rotates in the reverse direction. Therefore, as shown in the graph in the middle of FIG. 12 (described later), the angular velocity of the balance wheel 31 is symmetrical when it rotates in the forward direction and when it rotates in the reverse direction.

[0088] [Modification of the structure for reducing the angular velocity of the balance wheel 31] Here, modified examples of the structure for reducing the angular velocity of the balance wheel 31 will be described with reference to Figures 11A to 11J. Figures 11A to 11I are perspective views showing the balance wheel and air resistance member in a modified example of this embodiment. Figure 11J is a perspective view showing the balance wheel and elastic member in a modified example of this embodiment.

[0089] The balance wheel 31 shown in Fig. 11A has three notches 313A provided in the acted portion 313 of the balance wheel 31 shown in Fig. 10 so as to form resistance walls that intersect in the circumferential direction. The notches 313A are formed so as to pass through the air resistance area AR as the balance wheel 31 rotates.

[0090] The balance wheel 31 shown in Fig. 11B is the same as the balance wheel 31 shown in Fig. 10, except that three grooves 313B extending in the radial direction are provided in the acted-on portion 313 so as to form resistance walls that intersect in the circumferential direction. The grooves 313B are formed so as to pass through the air resistance area AR as the balance wheel 31 rotates.

[0091] The balance wheel 31 shown in Fig. 11C is configured such that three through holes 313C are provided in the acted portion 313 of the balance wheel 31 shown in Fig. 10 so as to form resistance walls that intersect in the circumferential direction. The through holes 313C are formed so as to pass through the air resistance area AR as the balance wheel 31 rotates.

[0092] 11A to 11C, when the acted upon portion 313 passes through the air resistance area AR, the air flow within the air resistance area AR is disturbed, increasing the air resistance experienced by the acted upon portion 313. This allows the speed of the acted upon portion 313 passing through the air resistance area AR to be reduced.

[0093] 11A to 11C are merely examples, and are not limited to these as long as the shape has a recessed portion where a resistance wall that increases air resistance is formed. In other words, the positions where notches and the like are formed and their number are not limited to those shown in the drawings.

[0094] 11D shows an example in which the third wall portion 153 of the air resistance member 15 shown in FIG. 10 is removed, and the first wall portion 151 and the second wall portion 152 are provided radially inward from the path of the acted upon portion 313. In other words, the air resistance member 15 defines the air resistance region AR only with the first wall portion 151 and the second wall portion 152 that face each other. It is preferable that the first wall portion 151 and the second wall portion 152 are each independently attached to the base plate 10 or the like.

[0095] 11D, the acted upon portion 313 protrudes radially inward. Therefore, the acted upon portion 313 passes through the air resistance area AR in accordance with the rotational movement of the balance wheel 31. The configuration shown in FIG. 11D can prevent the balance wheel 31 and the air resistance member 15 from becoming large in the radial direction.

[0096] 11E shows an example in which the acted-on portion 313 is provided at a position different from the circular portion 312 in the axial direction of the balance shaft 311. In addition, the air resistance member 15 is provided at a position in the axial direction of the balance shaft 311 where the acted-on portion 313 can pass through the air resistance area AR.

[0097] 11E, in FIG. 11F, the acted-on portion 313 is provided at a different position from the circular portion 312 in the axial direction of the balance arbour 311. Moreover, the air resistance member 15 is provided at a position in the axial direction of the balance arbour 311 where the acted-on portion 313 can pass through the air resistance area AR. Furthermore, the circular portion 312 of the balance wheel 31 has a semicircular shape. This reduces the weight of the balance wheel 31.

[0098] In the examples shown in FIGS. 11E and 11F, the acted-on portion 313 is provided at a position different from the circular portion 312 in the axial direction, so that the position of the center of gravity of the balance wheel 31 can be adjusted.

[0099] FIG. 11G shows an example in which the diameter of the circular portion 312 is smaller than that of the balance wheel 31 shown in FIG. 10, and the thickness is increased at the position facing the acted upon portion 313 across the balance arbour 311. In other words, the weight of the circular portion 312 is increased at the position facing the acted upon portion 313 across the balance arbour 311. With this configuration, the position of the center of gravity of the balance wheel 31 can be aligned with the balance arbour 311 (the center position of the balance wheel 31). Furthermore, the configuration of FIG. 11G in which the diameter of the balance wheel 31 is reduced has the advantage of improving the degree of freedom in the layout of the balance stud 34 that fixes the outer end of the hairspring 32.

[0100] 11H shows an example in which air resistance member 15 does not have first wall portion 151 or second wall portion 152, but includes only a configuration corresponding to third wall portion 153. That is, air resistance member 15 in FIG. 11H is made up of base portion 154 and third wall portion 153 that stands up from base portion 154 and has a shape that follows the rotation trajectory of balance wheel 31.

[0101] 11I shows an example in which grooves 153I, which are recesses that form resistance walls that intersect with the circumferential direction of the balance wheel 31, are formed in the air resistance member 15 shown in FIG. 11H. A plurality of grooves 153I are formed along the axial direction of the balance arbour 311. With this configuration, it is possible to increase the air resistance acting on the acted portion 313 that passes through the air resistance area AR, compared to FIG. 11H.

[0102] 11J shows an example in which the speed of the balance wheel 31 is reduced by contact resistance (friction resistance) rather than air resistance. Specifically, the balance wheel 31 has a protrusion 316 formed on the circular part 312 as the acted part. Also, an elastic member is used as the friction resistance part.

[0103] Specifically, there is provided a first elastic member 151J with which the protrusion 316 comes into contact when the balance wheel 31 is positioned at a rotation angle of 135°, and a second elastic member 152J with which the protrusion 316 comes into contact when the balance wheel 31 is positioned at a rotation angle of 225°. The first elastic member 151J and the second elastic member 152J may have their ends fixed to the main plate 10.

[0104] When the first elastic member 151J and the second elastic member 152J come into contact with the protrusion 316 of the balance wheel 31, the first elastic member 151J and the second elastic member 152J are elastically deformed while generating frictional resistance between them and the protrusion 316. While the balance wheel 31 is in contact with the protrusion 316, the speed of the balance wheel 31 is reduced by the frictional resistance. In the example shown in Fig. 11J, the region through which the protrusion 316 passes while in contact with the first elastic member 151J and the second elastic member 151J is the resistance region R1.

[0105] Note that the configurations shown in Figures 10 and 11A to 11J are merely examples, and any configuration that acts on the balance wheel 31 during the intermediate periods of both the forward and reverse motions to decelerate the balance wheel 31 is acceptable, and is not limited to the examples shown.

[0106] Further, with reference to Figures 11K and 11L, another example of the balance wheel 31 will be described. Figure 11K is a perspective view showing another example of the balance wheel as seen from the side where the hairspring is provided. Figure 11L is a perspective view showing the balance wheel shown in Figure 11K as seen from the side opposite to the side where the hairspring is provided.

[0107] 11K and 11L has a circular portion 312 and an acted upon portion 313, similar to that shown in Fig. 10 etc. Also, an opening 312h is formed in the circular portion 312 at a position overlapping with the acted upon portion 313 in the circumferential direction.

[0108] 11K and 11L, the edge 312a of the circular portion 312 protrudes in the axial direction of the balance arbour 311. That is, the edge 312a is thicker than the portion of the circular portion 312 that is on the inside of the edge 312a. The acted-on portion 313 is formed flush with the edge 312a. That is, the thickness of the acted-on portion 313 is the same as that of the edge 312a, and is thicker than the portion of the circular portion 312 that is on the inside of the edge 312a.

[0109] 11K and 11L, the acted upon portion 313 has a relatively large thickness, and therefore the surface of the acted upon portion 313 that is subjected to air resistance is relatively large. This increases the amount of air displaced by the acted upon portion 313 within the air resistance area AR shown in Fig. 10, making it easier to impede the movement of the balance wheel 31 and further slow down the balance wheel 31. Furthermore, since the hairspring 32 is disposed on a relatively thin portion of the balance wheel 31 other than the edge portion 312a and the acted upon portion 313, it becomes possible to reduce the total thickness of the hairspring 32 and the balance wheel 31 in the axial direction of the balance arbour 311.

[0110] 11L, the thickness of the surface of the circular portion 312 of the balance wheel 31 opposite to the side where the hairspring 32 is provided is partially increased. If the thickness of the acted upon portion 313 is increased, the weight of the acted upon portion 313 increases, and the center of gravity of the balance wheel 31 moves closer to the acted upon portion 313, but by partially increasing the thickness of the circular portion 312, the position of the center of gravity of the balance wheel 31 can be aligned with the balance arbour 311 (the center position of the balance wheel 31).

[0111] 11M to 11O, the balance spring 32 will be described in detail. Fig. 11M is a plan view showing the balance spring in a neutral position for its elastic deformation. Fig. 11N is a plan view showing the balance spring in an elastically deformed state in the expansion direction from the neutral position. Fig. 11O is a plan view showing the balance spring in an elastically deformed state in the contraction direction from the neutral position.

[0112] The hairspring 32 has an outer end 321 connected to the hairspring holder 34 and an inner end 322 connected to the balance axle 311. The inner end 322 is annular and follows the circumferential surface of the balance axle 311. The outer end 321 and the inner end 322 are thicker than other portions (portions that are elastically deformed) of the hairspring 32. This maintains the strength of the connection to the hairspring holder 34 and the balance axle 311.

[0113] By increasing the overall length of the hairspring 32, the spring force of the hairspring 32 can be reduced, thereby achieving low vibration. However, increasing the overall length of the hairspring 32 increases the diameter of the hairspring 32. In order to increase the overall length of the hairspring 32 while reducing its size, it is advisable to shorten the distance between the inner and outer portions of the hairspring 32. In other words, it is advisable to narrow the pitch of the hairspring 32.

[0114] The hairspring 32 has a logarithmic spiral shape. As described above, a logarithmic spiral hairspring can be easily manufactured by laser processing. By adopting a logarithmic spiral shape, the distance between the pitches of the hairspring 32 on the inner end 322 side can be made smaller than the uniform-pitch Archimedes' spiral commonly used for hairsprings. This allows the hairspring to have a longer overall length and a smaller diameter. As a result, the hairspring 32 can have a smaller diameter, and its spring force can be reduced, resulting in lower vibrations. However, when manufacturing the hairspring 32 by laser processing as described above, it is difficult to narrow the pitch. This is because the heat of the laser light can deform the shape of the hairspring 32.

[0115] Therefore, in order to maintain the dimensional accuracy of the hairspring 32 while narrowing the pitch, the inner end portion 322 is configured to include a fixed portion 322a and an enlarged pitch portion 322b, as shown in FIGS. 11M to 11O. The fixed portion 322a is a portion that is fixed to the balance axle 311. The enlarged pitch portion 322b is a portion narrower than the fixed portion 322a and enlarges the pitch between the inner end portion 322 and a portion 323 of the hairspring 32 that is adjacent to the inner end portion 322 in the radial direction. The portion 323 of the hairspring 32 that is adjacent to the inner end portion 322 in the radial direction is the portion other than the inner end portion 322 and is located innermost. W in FIGS. 11M to 11O indicates the distance between the inner end portion 322 and the portion 323 that is adjacent to the inner end portion 322 in the radial direction.

[0116] 11M to 11O show an example in which the inner end portion 322 is annular, i.e., an example in which the fixed portion 322a and the pitch enlarged portion 322b are connected, but this is not limited to this. For example, the inner end portion 322 may be partially separated in the circumferential direction, with the separated portion functioning as the pitch enlarged portion 322b. However, an annular inner end portion 322 makes it easier to ensure the strength of the fixation to the balance arbour 311. While FIGS. 11M to 11O show an example in which the hairspring 32 has a logarithmic spiral shape, this is not limiting, and a configuration in which the pitch enlarged portion 322b is formed is particularly effective for a hairspring having a shape in which the pitch is narrower on the inside of the diameter than on the outside of the diameter.

[0117] [Regarding power generation timing] The amount of current generated in the coil 43 due to the movement of the permanent magnet 41 increases in proportion to the angular velocity of the permanent magnet 41. Therefore, in order to generate power efficiently, it is preferable to use the current generated in the coil 43 when the angular velocity of the permanent magnet 41 is high.

[0118] Therefore, in this embodiment, power is generated based on a current corresponding to the back electromotive force (detected voltage) detected by the coil 43 due to the movement of the permanent magnet 41 when the permanent magnet 41 (balance wheel 31) is at the 0° position or immediately thereafter. That is, as shown in the lower graph of Fig. 12, power is generated at the timing when the back electromotive force detected by the coil 43 peaks.

[0119] The timing for generating power is not limited to the timing when the balance wheel 31 is at the rotation angle 0° position or the timing immediately thereafter, but may be any timing before the acted upon part 313 (balance wheel 31) reaches the position of the air resistance member 15 in either the forward movement or the reverse movement of the forward and reverse rotational movement of the balance wheel 31. In other words, power may be generated based on the current corresponding to the back electromotive force detected by the coil 43 during the period before the acted upon part 313 receives air resistance from the air resistance member 15 and the angular velocity of the balance wheel 31 decreases.

[0120] 12, in this embodiment, the voltage waveforms detected are the same for the forward and backward movements of the balance wheel 31. Therefore, in the mechanical timepiece 1, in order to time the power generation, it is not necessary to know whether the balance wheel 31 is moving in the forward or backward direction.

[0121] [Relationship between the magnetization direction of the permanent magnet 41 and power generation efficiency] Here, the relationship between the magnetization direction of permanent magnet 41 and power generation efficiency will be described with reference to FIGS. 5, 12, and 13A to 13C.

[0122] In the mechanical timepiece 1 according to this embodiment, power is generated based on the power obtained by rectifying the current corresponding to the back electromotive force generated in the coil 43 using the rectifier circuit 50. The rectification performed by the rectifier circuit 50 can be full-wave rectification using a bridge circuit including multiple diodes, or half-wave rectification using a circuit including a single diode. When multiple diodes are used, a voltage drop occurs depending on the number of diodes, resulting in a corresponding loss in the power obtained. Therefore, in this embodiment, a configuration in which the rectifier circuit 50 performs half-wave rectification is adopted. Furthermore, in half-wave rectification, the positive and negative back electromotive forces have different shapes, and power is generated based on the back electromotive force with the larger absolute value, thereby achieving efficient power generation. Therefore, in this embodiment, the permanent magnet 41 is positioned so that a back electromotive force suitable for half-wave rectification can be detected.

[0123] Fig. 13A shows the back electromotive force detected by the coil 43 in the arrangement of the permanent magnet 41 of this embodiment. Fig. 13B shows the back electromotive force detected by the coil 43 in the arrangement of the permanent magnet 41 of Comparative Example 1. Fig. 13C shows the back electromotive force detected by the coil 43 in the arrangement of the permanent magnet 41 of Comparative Example 2.

[0124] [Relationship between the magnetization direction of the permanent magnet 41 and the power generation efficiency: this embodiment] In this embodiment, the permanent magnet 41 is arranged so that the magnetization direction is perpendicular to the opposing direction of the first welded portion 423 and the second welded portion 424 when the hairspring 32 is in its neutral position of elastic deformation.

[0125] Here, we will explain the back electromotive force detected by coil 43 as permanent magnet 41 rotates in the forward direction from the rotation angle position of 0°, rotates in the reverse direction due to the elastic force of hairspring 32, and then rotates again in the forward direction due to the elastic force of hairspring 32.

[0126] Furthermore, the back electromotive force generated in the coil 43 due to a change in the magnetic field when the N-pole portion 411 of the permanent magnet 41 moves in a direction toward the first end 421a of the soft magnetic core 42 is defined as a "positive" back electromotive force. On the other hand, the back electromotive force generated in the coil 43 due to a change in the magnetic field when the N-pole portion 411 moves in a direction away from the first end 421a of the soft magnetic core 42 is defined as a "negative" back electromotive force.

[0127] In this embodiment, the permanent magnet 41 is in a magnetically balanced position at a rotation angle of 0°. Therefore, the back electromotive force generated in the coil 43 is zero at a rotation angle of 0°. The permanent magnet 41 is supplied with power from the power spring 11 at a rotation angle of 0°. That is, the angular velocity of the permanent magnet 41 reaches a maximum immediately after the rotation angle reaches 0°. Furthermore, while the permanent magnet 41 rotates in the forward direction from a rotation angle of 0° to 180°, the N-pole portion 411 moves in a direction approaching the first end 421a. Thus, in this embodiment, the permanent magnet 41 is disposed so that the back electromotive force detected in the coil 43 has the same polarity during the forward rotation of 180° from the power supply position.

[0128] Therefore, while the permanent magnet 41 rotates from a rotation angle of 0° to 180°, the angular velocity of the permanent magnet 41 reaches a maximum, and the positive back electromotive force generated in the coil 43 reaches a peak.

[0129] At a rotation angle of 180°, where the permanent magnet 41 is in a magnetically balanced position, the back electromotive force generated in the coil 43 becomes zero.

[0130] When the permanent magnet 41 rotates in the positive direction from a rotation angle of 180°, the N-pole portion 411 moves in a direction away from the first end 421a. Therefore, a negative back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from a rotation angle of 180° to 340°. The angular velocity of the permanent magnet 41 at this time is smaller than the angular velocity when the permanent magnet 41 moves from a rotation angle of 0° to 180°. Therefore, the absolute value of the peak of the negative back electromotive force is smaller than the absolute value of the peak of the positive back electromotive force.

[0131] Furthermore, the angular velocity of permanent magnet 41 becomes 0 at a rotation angle of 340°, which is the turning point of the reciprocating motion. Therefore, the back electromotive force generated in coil 43 becomes 0 at a rotation angle of 340°.

[0132] When the permanent magnet 41 reaches a rotation angle of 340°, it starts to rotate in the reverse direction due to the elastic force of the hairspring 32. When the permanent magnet 41 rotates from a rotation angle of 340° to 180°, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, a positive back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from a rotation angle of 340° to 180°.

[0133] Furthermore, at a rotation angle of 180°, where the permanent magnet 41 is in a magnetically balanced position, the back electromotive force generated in the coil 43 becomes zero.

[0134] Furthermore, the permanent magnet 41 rotates from a rotation angle of 180° to 0°. When the permanent magnet 41 rotates from a rotation angle of 180° to 0°, the N-pole portion 411 moves in a direction away from the first end 421a. Therefore, when the permanent magnet 41 rotates from a rotation angle of 180° to 0°, a negative back electromotive force is generated in the coil 43.

[0135] Furthermore, at a rotation angle of 0°, where the permanent magnet 41 is in a magnetically balanced position, the back electromotive force generated in the coil 43 is zero.

[0136] When the permanent magnet 41 reaches a rotation angle of 0°, power is supplied from the power spring 11. That is, the angular velocity of the permanent magnet 41 reaches a maximum immediately after the rotation angle reaches 0°. Furthermore, while the permanent magnet 41 rotates from a rotation angle of 0° to -180°, the N-pole portion 411 moves in a direction approaching the first end 421a. Thus, in this embodiment, the permanent magnet 41 is disposed so that the back electromotive force detected in the coil 43 during the rotation from the power supply position to -180° in the reverse direction has the same polarity.

[0137] Therefore, while the permanent magnet 41 rotates from a rotation angle of 0° to −180°, the angular velocity of the permanent magnet 41 reaches a maximum, and the positive back electromotive force generated in the coil 43 reaches a peak.

[0138] At a rotation angle of −180°, where the permanent magnet 41 is in a magnetically balanced position, the back electromotive force generated in the coil 43 becomes zero.

[0139] When the permanent magnet 41 rotates in the reverse direction from a rotation angle of -180°, the N-pole portion 411 moves in a direction away from the first end 421a. Therefore, a negative back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from a rotation angle of -180° to -340°. The angular velocity of the permanent magnet 41 at this time is lower than the angular velocity when the permanent magnet 41 moves from a rotation angle of 0° to -180°. Therefore, the absolute value of the peak of the negative back electromotive force is smaller than the absolute value of the peak of the positive back electromotive force.

[0140] Furthermore, the angular velocity of the permanent magnet becomes 0 at a rotation angle of −340°, which is the turning point of the reciprocating motion. Therefore, the back electromotive force generated in the coil 43 becomes 0 at a rotation angle of −340°.

[0141] When the permanent magnet 41 reaches a rotation angle of -340°, it starts to rotate in the forward direction due to the elastic force of the hairspring 32. When the permanent magnet 41 rotates from a rotation angle of -340° to -180°, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, a positive back electromotive force is generated in the coil 43 while the permanent magnet 41 rotates from a rotation angle of -340° to -180°.

[0142] Furthermore, at a rotation angle of −180°, where the permanent magnet 41 is in a magnetically balanced position, the back electromotive force generated in the coil 43 becomes zero.

[0143] Furthermore, the permanent magnet 41 rotates from a rotation angle of -180° to 0°. When the permanent magnet 41 rotates from a rotation angle of -180° to 0°, the N-pole portion 411 moves in a direction away from the first end 421a. Therefore, when the permanent magnet 41 rotates from a rotation angle of -180° to 0°, a negative back electromotive force is generated in the coil 43.

[0144] By repeating the above-described operation, in the arrangement of the permanent magnet 41 of this embodiment, a back electromotive force voltage with the waveform shown in FIG. 13A is generated in the coil 43. As shown in FIG. 13A, the peaks of the back electromotive force voltage differ between the positive back electromotive force voltage and the negative back electromotive force voltage. That is, the maximum absolute value of the positive back electromotive force voltage is greater than the maximum absolute value of the negative back electromotive force voltage. Furthermore, the waveform of the detected back electromotive force voltage is the same when the permanent magnet 41 moves in the forward direction and when it moves in the reverse direction.

[0145] [Relationship between magnetization direction of permanent magnet 41 and power generation efficiency: Comparative Example 1] Next, comparative example 1 will be described with reference to Fig. 13B. In comparative example 1, permanent magnet 41 is arranged so that the magnetization direction is tilted by 45° toward the opposing direction of first welded portion 423 and second welded portion 424 when hairspring 32 is in the neutral position of its elastic deformation. That is, in comparative example 1, the position of a rotation angle of 0° is tilted by -45° from that of this embodiment.

[0146] In Comparative Example 1, when the permanent magnet 41 rotates in the positive direction from a rotation angle of 0°, the N-pole portion 411 first moves in a direction away from the first end 421a. Then, when the permanent magnet 41 passes a rotation angle of 45°, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, while the permanent magnet 41 rotates in the positive direction from a rotation angle of 0° to 225°, a negative back electromotive force is generated in the coil 43 immediately after the rotation, and then, after the rotation angle passes 45°, a positive back electromotive force is generated in the coil 43.

[0147] In Comparative Example 1, the permanent magnet 41 rotates in the forward direction from a rotation angle of 0° to 340°, rotates in the reverse direction due to the elastic force of the hairspring 32, and returns to the rotation angle of 0° again. When the permanent magnet 41 rotates in the reverse direction from the rotation angle of 0°, the N-pole portion 411 moves in a direction approaching the first end 421a. In other words, when the permanent magnet 41 rotates in the reverse direction from the rotation angle of 0°, a positive back electromotive force is generated in the coil 43.

[0148] As described above, in Comparative Example 1, the waveforms of the positive back electromotive force and the negative back electromotive force are different at least around 0° of rotation angle in the forward and reverse directions of rotation. Therefore, the magnitude of the peak of the back electromotive force is different in the forward and reverse directions of rotation. Furthermore, because the peak position of the back electromotive force is different in the forward and reverse directions of rotation, it may be determined that the period of the forward and reverse rotational motion of the balance wheel 31 is disrupted, which may result in erroneous rate adjustment. Therefore, in the configuration of Comparative Example 1, the rate adjustment means 40 needs to have a means for determining in advance whether the balance wheel 31 is moving in the forward direction or the reverse direction.

[0149] [Relationship between magnetization direction of permanent magnet 41 and power generation efficiency: Comparative Example 2] Next, comparative example 2 will be described with reference to Fig. 13C. In comparative example 2, permanent magnet 41 is arranged so that the magnetization direction is the same as the opposing direction of first welded portion 423 and second welded portion 424 when hairspring 32 is in the neutral position of its elastic deformation. That is, in comparative example 2, the position of a rotation angle of 0° is arranged at an angle of -90° compared to the present embodiment.

[0150] In Comparative Example 2, when the permanent magnet 41 rotates in the positive direction from a rotation angle of 0°, the N-pole portion 411 first moves in a direction away from the first end 421a. Then, when the permanent magnet 41 passes a rotation angle of 90°, the N-pole portion 411 moves in a direction approaching the first end 421a. Therefore, while the permanent magnet 41 rotates in the positive direction from a rotation angle of 0° to 180°, a negative back electromotive force is generated in the coil 43 immediately after the rotation, and then, after the rotation angle passes 90°, a positive back electromotive force is generated in the coil 43.

[0151] In Comparative Example 2, the permanent magnet 41 rotates in the forward direction from a rotation angle of 0° to 340°, rotates in the reverse direction due to the elastic force of the hairspring 32, and returns to the rotation angle of 0° again. When the permanent magnet 41 rotates in the reverse direction from the rotation angle of 0°, the N-pole portion 411 moves in a direction approaching the first end 421a. In other words, when the permanent magnet 41 rotates in the reverse direction from the rotation angle of 0°, a positive back electromotive force is generated in the coil 43.

[0152] As described above, in Comparative Example 2, the waveforms of the positive and negative back electromotive force voltages are different at least around 0° of rotation angle in the forward and reverse directions of rotation. Therefore, the magnitude of the peak of the back electromotive force voltage is different in the forward and reverse directions of rotation. In the configuration of Comparative Example 2, the peak of the back electromotive force voltage is smaller in the forward and reverse directions of rotation than in Comparative Example 1, and it cannot be said that the back electromotive force voltage is suitable for half-wave rectification. Furthermore, since the peak of the back electromotive force voltage differs between the forward and reverse directions of rotation, it may be necessary to change the threshold value Vth in some cases. As a result, as in Comparative Example 1, the rate adjustment means 40 needs to have a means for determining in advance whether the balance wheel 31 is moving in the forward direction or the reverse direction.

[0153] [Relationship between the magnetization direction of permanent magnet 41 and power generation efficiency: Summary] As described above, in this embodiment, a back electromotive force having the same waveform is detected regardless of whether the rotation direction of the permanent magnet 41 is forward or reverse. Therefore, in this embodiment, peaks of the positive back electromotive force are detected with the same magnitude and at a constant period. Furthermore, in this embodiment, the shapes of the positive and negative back electromotive force are asymmetric. Specifically, the peaks of the positive back electromotive force are larger than the peaks of the negative back electromotive force. Therefore, the arrangement of the permanent magnet 41 in this embodiment can be said to produce a back electromotive force with a waveform that is more suitable for rate adjustment and half-wave rectification than those in Comparative Examples 1 and 2.

[0154] 5 is an example, and the permanent magnet 41 is preferably arranged so that its magnetization direction is the same as the opposing direction of the first end 421a and the second end 422a when the hairspring 32 is in the neutral position of its elastic deformation. The opposing direction of the first end 421a and the second end 422a is a direction perpendicular to the opposing direction of the first welded portion 423 and the second welded portion 424 shown in FIG. 5. However, the arrangement is not limited to this, and it is preferable that the magnetization direction of the permanent magnet 41 faces the first end 421a or the second end 422a at least when the hairspring 32 is in the neutral position of its elastic deformation.

[0155] Furthermore, the permanent magnet 41 is preferably arranged so that, when the balance spring 32 is in its neutral position of elastic deformation, the boundary B between the north pole portion 411 and the south pole portion 412 overlaps with an imaginary band-shaped region (S shown in FIG. 5 ) connecting the first welded portion 423 and the second welded portion 424. Note that the band-shaped region S is an imaginary region defined for the sake of convenience to indicate the arrangement of the permanent magnet 41, and does not physically exist as part of the configuration of the mechanical timepiece 1.

[0156] [Circuit diagram] An overview of the rectifier circuit in this embodiment will now be described with reference to Fig. 14A, which is a circuit diagram showing an example of a circuit in this embodiment.

[0157] In this embodiment, a configuration is adopted in which a rectifier circuit 50 including one diode D is used to half-wave rectify a current corresponding to the back electromotive force generated in the coil 43 by the movement of the permanent magnet 41. The rectifier circuit 50 is a circuit that eliminates the negative voltage portion of the back electromotive force generated in the coil 43 and converts it into direct current.

[0158] Transistors TP1 and TP2 are connected to the first terminal O1 and the second terminal O2, respectively, of the coil 43. The back electromotive force generated in the coil 43 is input to the transistors TP1 and TP2, and the rotation detection circuit 45 detects a detection signal based on the back electromotive force. That is, by turning on the transistors TP1 and TP2 at a predetermined timing, the induced voltages generated at the first terminal O1 and the second terminal O2 corresponding to these transistors can be extracted as detection signals, which are voltage signals.

[0159] Furthermore, transistors P11 and P12 are connected to a first terminal O1 of the coil 43, and transistors P21 and P22 are connected to a second terminal O2 of the coil 43. The transistors P11, P12, P21, and P22 are ON / OFF controlled by a speed control pulse from a speed control pulse output circuit 46. During power generation, the gate terminals of the transistors P11, P12, P21, and P22 are turned OFF. In this state, the transistors TP1 and TP2 and the diode D form a rectifier circuit 50. As the permanent magnet 41 rotates forward and backward, current flows through the coil 43 and charges the capacitor C. When a certain amount of charge is stored in the capacitor C, the power supply circuit 60 is activated. When the power supply circuit 60 is activated, the control circuit 44 is activated, and the control circuit 44 controls each circuit included in the rate adjustment means 40.

[0160] In this embodiment, as shown in FIG. 14A, a configuration is adopted in which half-wave rectification is performed using a rectifier circuit 50 including one diode D, thereby simplifying the circuit configuration and making it less likely for a voltage drop to occur. Note that the circuit shown in FIG. 14A is just one example, and as shown in FIG. 14B, a voltage doubler rectifier circuit that can also rectify a back electromotive force in the reverse direction may be used as the rectifier circuit 50. FIG. 14B shows an example of a voltage doubler rectifier circuit including two diodes D1 and D2 and two capacitors C1 and C2. In a voltage doubler rectifier circuit, the number of diodes can be reduced compared to a full-wave rectifier circuit. In other words, it is possible to make it less likely for a voltage drop to occur.

[0161] [Details about the rate adjustment control] Hereinafter, the rate adjustment control in this embodiment will be described in detail with reference to Fig. 12 and Fig. 15A to Fig. 19. Fig. 15A and Fig. 15B are diagrams for explaining the control of the movement of the permanent magnet by the speed control pulse in this embodiment.

[0162] In this 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 adjusting the rate.

[0163] In this embodiment, as shown in Fig. 15A, when a speed control pulse is output to the first terminal O1 of the coil 43, the first end 421a is defined as having an S pole and the second end 422a is defined as having an N pole. On the other hand, as shown in Fig. 15B, when a speed control pulse is output to the terminal O2 of the coil 43, the first end 421a is defined as having an N pole and the second end 422a is defined as having an S pole. Note that when the winding direction of the coil 43 is reversed, the polarities of the first end 421a and the second end 422a are reversed.

[0164] [Details of rate adjustment control: Output timing of speed control pulse] Here, when the angular velocity of the permanent magnet 41 is high, it is difficult to adjust the rate at the desired timing. This is because when the angular velocity of the permanent magnet 41 is high, there is a high possibility that the output timing of the speed control pulse will be off.

[0165] Therefore, in this embodiment, during the forward and reverse rotational motion of the permanent magnet 41, a speed control pulse is output 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°. In other words, a speed control pulse is output during the period before the balance wheel 31 receives power from the power spring 11. This allows the speed control pulse to be output when the angular velocity of the permanent magnet 41 is relatively slow. Furthermore, in this embodiment, the balance wheel 31 experiences air resistance from the air resistance member 15 between rotation angles of 225° and 135°, so the angular velocity of the permanent magnet 41 is particularly slow during the period between rotation angles of 180° and 0°. The same is true for the period between rotation angles of −225° and −135°. Thus, during the forward and reverse rotational motion of the balance wheel 31, it is preferable to perform rate adjustment during the period after the acted part 313 reaches the position of the air resistance member 15.

[0166] By adopting such a configuration, deviations in the output timing of the speed control pulse can be suppressed. As a result, rate accuracy can be maintained. In FIG. 12, the timing for rate adjustment is indicated by a band-shaped area. As shown in the upper graph of FIG. 12, rate adjustment is performed during the period when the angular velocity of the permanent magnet 41 is slow.

[0167] [Details about rate adjustment control: Coil terminal where the rate adjustment pulse is output] Figure 15A shows an example in which a speed control pulse is output to coil 43 at the timing when permanent magnet 41 rotating in the forward direction is at a rotation angle of -90° and at the timing when permanent magnet 41 rotating in the reverse direction is at a rotation angle of 90°.

[0168] As shown in Fig. 15A, if a speed control pulse is output to the first terminal O1 of the coil 43 when the permanent magnet 41 rotates in the forward direction from a rotation angle of -90°, the permanent magnet 41 will be subjected to a repulsive force from the soft magnetic core 42. In other words, the forward rotation of the permanent magnet 41 will be braked. On the other hand, if a speed control pulse is output to the first terminal O1 of the coil 43 when the permanent magnet 41 rotates in the reverse direction from a rotation angle of 90°, the permanent magnet 41 will be subjected to a repulsive force from the soft magnetic core 42. In other words, the reverse rotation of the permanent magnet 41 will be braked.

[0169] 15B, when a speed control pulse is output to the second terminal O2 of the coil 43 as the permanent magnet 41 rotates in the forward direction from a rotation angle of -90°, the permanent magnet 41 receives an attractive force from the soft magnetic core 42. In other words, the forward rotation of the permanent magnet 41 is accelerated. On the other hand, when a speed control pulse is output to the second terminal O2 of the coil 43 as the permanent magnet 41 rotates in the reverse direction from a rotation angle of 90°, the permanent magnet 41 receives an attractive force from the soft magnetic core 42. In other words, the reverse rotation of the permanent magnet 41 is accelerated.

[0170] In this manner, in this embodiment, regardless of whether the permanent magnet 41 is rotating in the forward or reverse direction of its forward / reverse rotational motion, the rotation of the permanent magnet 41 can be weakened by outputting a speed control pulse to the first terminal O1, while the rotation of the permanent magnet 41 can be strengthened by outputting a speed control pulse to the second terminal O2.

[0171] In other words, regardless of whether the permanent magnet 41 is rotating in the forward or reverse direction, if the rate is to be adjusted to delay, it is sufficient to energize the first terminal O1, and if the rate is to be adjusted to advance, it is sufficient to energize the second terminal O2.

[0172] [Details of the rate adjustment control: Rate adjustment control operation flow] 16 is a flowchart showing an example of rate adjustment control according to this embodiment. In the following description, a signal detected by the rotation detection circuit 45 when a back electromotive force equal to or greater than a predetermined threshold Vth is generated is defined as a detection signal DE. The control circuit 44 controls the speed adjusting pulse output circuit 46 based on the detection signal DE detected by the rotation detection circuit 45 and the reference signal OS generated by the frequency divider circuit 47.

[0173] The detection signal DE is detected when a large back electromotive force is generated in the coil 43. In other words, this is when the angular velocity of the permanent magnet 41 is fast. Therefore, the control circuit 44 may perform rate adjustment based on the detection voltage generated in the coil 43 by the movement of the permanent magnet 41 before the acted part 313 reaches the position of the air resistance member 15 during the forward and reverse rotational movements of the balance wheel 31, and on the reference signal OS.

[0174] In this embodiment, after the power supply circuit 60 is started up by the motion of the permanent magnet 41 generating electricity (Y in ST1), the rate adjustment means 40 performs rate adjustment control.

[0175] If the detection signal DE is detected within the output period of the reference signal OS (Y in ST2), that is, if no rate deviation occurs, the rate adjustment control is terminated. Note that FIG. 17 is a timing chart showing an example in which the detection signal is detected within the output period of the reference signal. As shown in FIG. 17, in this embodiment, the output period of the reference signal OS is set to an output period ts having a predetermined width.

[0176] If the detection signal DE is not detected within the output period of the reference signal OS (N in ST2), that is, if a rate deviation occurs, the control circuit 44 determines whether the detection timing of the detection signal DE is earlier than the output period of the reference signal OS (ST3).

[0177] If the detection timing of the detection signal DE is earlier than the output period of the reference signal OS (Y in ST3), the control circuit 44 controls the speed control pulse output circuit 46 to output a speed control pulse to the terminal O1 (ST4).

[0178] 18 is a timing chart showing an example in which the detection timing of the detection signal is earlier than the output period of the reference signal. Fig. 18 shows an example in which the speed control pulse p1 is output to the first terminal O1 of the coil 43 at a timing when a time tp1 has elapsed since the detection timing of the detection signal DE. As shown in Fig. 18, the cycle in which the detection signal DE is detected differs before and after the output of the speed control pulse p1. That is, the cycle in which the detection signal DE is detected after the speed control pulse p1 is output is longer than the cycle in which the detection signal DE is detected before the speed control pulse p1 is output. As a result, after the speed control pulse p1 is output, the detection signal DE is detected within the output period ts of the reference signal OS.

[0179] If the detection timing of the detection signal DE is later than the reference signal OS (N in ST3), the control circuit 44 controls the speed control pulse output circuit 46 to output a speed control pulse to the terminal O2 (ST5).

[0180] 19 is a timing chart showing an example in which the timing at which the detection signal is detected is later than the output period of the reference signal OS. Fig. 19 shows an example in which the speed control pulse p2 is output to the second terminal O2 of the coil 43 at a timing when a time tp2 has elapsed since the detection timing of the detection signal DE. As shown in Fig. 19, the cycle at which the detection signal DE is detected differs before and after the output of the speed control pulse p2. That is, the cycle at which the detection signal DE is detected after the speed control pulse p2 is output is shorter than the cycle at which the detection signal DE is detected before the speed control pulse p2 is output. As a result, after the speed control pulse p2 is output, the detection signal DE is detected within the output period ts of the reference signal OS.

[0181] The speed control pulse p1 output to the first terminal O1 and the speed control pulse p2 output to the second terminal O2 may have different output timings and periods, because the amount of correction caused by the output of the speed control pulse may differ between the direction in which the permanent magnet 41 advances and the direction in which it delays.

[0182] [Details of Rate Adjustment Control: Operation Flow of First Modified Example of Rate Adjustment Control] Next, a first modified example of rate adjustment control will be described with reference to Figures 20 and 21. Figure 20 is a flowchart showing the first modified example of rate adjustment control.

[0183] In this example, the rate adjustment means 40 preferably has a first counter that counts the number of times the detection signal DE is detected, and a second counter that is an accumulation unit that accumulates the period difference between the detection signal DE and the reference signal OS (the amount of deviation in the detection timing of the detection signal DE from the output timing of the reference signal OS).

[0184] In the first modified example of the rate adjustment control, after the power supply circuit 60 is started up by the motion of the permanent magnet 41 generating electricity (Y in ST1), the rate adjustment means 40 performs the rate adjustment control.

[0185] The control circuit 44 determines whether the forward and reverse rotation of the balance wheel 31 (permanent magnet 41) is the eighth time. Specifically, the control circuit 44 determines whether the count number of the first counter is 8 (ST21).

[0186] If the count number of the first counter is not 8 (N in ST21), the period difference between the detection signal DE and the reference signal OS is calculated and the period difference is accumulated (ST22). After that, the count number of the first counter is incremented by 1 (ST23).

[0187] On the other hand, if the count number of the first counter is 8 (Y in ST21), the first counter is reset to 0 (ST24).

[0188] Then, the control circuit 44 determines whether the accumulated amount of the period difference between the detection signal DE and the reference signal OS is 0 or within a predetermined range (ST25). If the accumulated amount of the period difference between the detection signal DE and the reference signal OS is 0 or within a predetermined range, the control circuit 44 increments the count number of the first counter by 1 without performing rate adjustment (ST23).

[0189] If the accumulated amount of the period difference between the detection signal DE and the reference signal OS is positive (N in ST25, Y in ST26), the control circuit 44 controls the speed control pulse output circuit 46 to output a speed control pulse to the first terminal O1 (ST4).

[0190] On the other hand, if the accumulated amount of the period difference between the detection signal DE and the reference signal OS is negative (N in ST25, N in ST26), the control circuit 44 controls the speed control pulse output circuit 46 to output a speed control pulse to the second terminal O2 (ST5).

[0191] The upper part of Figure 21 shows an example in which, when the first counter is 2, the detection timing of the detection signal DE is t earlier than the output period of the reference signal OS; when the first counter is 3, the detection timing of the detection signal DE is 2t earlier than the output period of the reference signal OS; and when the first counter is 6, the detection timing of the detection signal DE is t later than the output period of the reference signal OS. In this example, the accumulated amount of the period difference becomes +2t by the time the first counter reaches 8. That is, the detection timing of the detection signal DE is 2t earlier than the reference signal OS in total. Therefore, the control circuit 44 outputs a speed control pulse to the first terminal O1 to delay the rate.

[0192] The lower part of Figure 21 shows an example in which, when the first counter is 2, the detection timing of the detection signal DE is 3t earlier than the output period of the reference signal OS; when the first counter is 3, the detection timing of the detection signal DE is 2t earlier than the output period of the reference signal OS; and when the first counter is 6, the detection timing of the detection signal DE is t later than the output period of the reference signal OS. In this example, the accumulated amount of the period difference becomes +4t by the time the first counter reaches 8. That is, the detection timing of the detection signal DE is 4t earlier than the reference signal OS in total. Therefore, a speed control pulse is output to the first terminal O1 to delay the rate.

[0193] Furthermore, in the example in the lower part of Fig. 21, the accumulated amount of period difference is larger than in the example in the upper part of Fig. 21, so the output period of the speed control pulse is made longer. Specifically, the output period p112 of the speed control pulse shown in the lower part of Fig. 22 is made longer than the output period p111 of the speed control pulse shown in the upper part of Fig. 22. Note that in both the examples in the upper and lower parts of Fig. 22, the speed control pulse is output at a timing when tp111 has elapsed since the reference signal OS, which is output when the first counter is at 8, is output. In other words, the output timing of the speed control pulse is the same regardless of the output period of the speed control pulse.

[0194] In the first modified example of the rate adjustment control described above, rate adjustment is not performed every second, so the number of times that rate adjustment pulses are output can be reduced, which results in reduced power consumption.

[0195] [Details of Rate Adjustment Control: Operation Flow of the Second Modified Example of Rate Adjustment Control] Next, a second modified example of rate adjustment control will be described with reference to Figures 22 and 23. Figure 22 is a flowchart showing the second modified example of rate adjustment control.

[0196] In this example, the rate adjustment means 40 preferably has a first counter that counts the number of times the detection signal DE is detected, and a second counter that is an accumulation unit that accumulates the period difference between the detection signal DE and the reference signal OS (the amount of deviation in the detection timing of the detection signal DE from the output timing of the reference signal OS).In the second modified example of the rate adjustment control, it is assumed that the second counter reaches a count of 7 when it is reset.

[0197] In the second modified example of the rate adjustment control, after the power supply circuit 60 is started up by the motion of the permanent magnet 41 generating electricity (Y in ST1), the rate adjustment means 40 performs the rate adjustment control.

[0198] The control circuit 44 determines whether the forward and reverse rotation of the balance wheel 31 (permanent magnet 41) is the eighth time. Specifically, the control circuit 44 determines whether the count number of the first counter is 8 (ST21).

[0199] If the count number of the first counter is not 8 (N in ST21), the control circuit 44 calculates the difference in period between the detection signal DE and the reference signal OS (ST31).

[0200] If the detection timing of the detection signal DE is within the output period of the reference signal OS (Y in ST32), the control circuit 44 adds 1 to the count number of the first counter without performing rate adjustment (ST23).

[0201] If the detection timing of the detection signal DE is not within the output period of the reference signal OS (N in ST32), the control circuit 44 determines whether the detection timing of the detection signal DE is earlier than the output period of the reference signal OS (ST33).

[0202] If the detection timing of the detection signal DE is earlier than the output period of the reference signal OS (Y in ST33), the second count is subtracted according to the period difference (ST34).If the detection timing of the detection signal DE is later than the output period of the reference signal OS (N in ST33), the second count is added according to the period difference (ST35).After that, the count number of the first counter is incremented by 1 (ST23).

[0203] If the count number of the first counter is 8 (Y in ST21), the first counter is reset to 0 (ST24).

[0204] Then, the control circuit 44 determines whether the count of the second counter is 7 or not (ST36). If the count of the second counter is 7 (Y in ST36), the control circuit 44 increments the count of the first counter by 1 without performing rate adjustment (ST23).

[0205] If the count number of the second counter is not 7 (N in ST36), the control circuit 44 determines whether the count number of the second counter is less than 7 (ST37). If the count number of the second counter is less than 7 (Y in ST37), the control circuit 44 controls the speed control pulse output circuit 46 to output a speed control pulse to the first terminal O1 (ST4). If the count number of the second counter is greater than 7 (N in ST37), the control circuit 44 controls the speed control pulse output circuit 46 to output a speed control pulse to the second terminal O2 (ST5). Thereafter, the count number of the second counter is reset to 7 (ST38).

[0206] In the second modified example of the rate adjustment control described above, rate adjustment is not performed every second, so the number of times that rate adjustment pulses are output can be reduced, resulting in reduced power consumption.

[0207] 23 shows an example in which, when the first counter is 2, the detection timing of the detection signal DE is t earlier than the output period of the reference signal OS; when the first counter is 3, the detection timing of the detection signal DE is 2t earlier than the output period of the reference signal OS; and when the first counter is 6, the detection timing of the detection signal DE is t later than the output period of the reference signal OS. In this example, by the time the first counter reaches 8, the second counter has reached 5. That is, the detection timing of the detection signal DE is 2t earlier than the reference signal OS in total. Therefore, the control circuit 44 outputs a speed control pulse to the first terminal O1 to delay the rate.

[0208] The speed control pulse is not limited to a single pulse, and may be composed of a pulse group including a plurality of single pulses as shown in FIG. 24. By using a speed control pulse composed of a pulse group, it is possible to absorb manufacturing variations and driving variations in the speed control mechanism 30. In this case, the attractive or repulsive force acting on the permanent magnet 41 may be controlled by changing the duty ratio of the speed control pulse, rather than changing the output period of the speed control pulse as shown in FIG. 21. The duty ratio indicates the proportion of pulses output within a predetermined period. FIG. 24 shows an example of a speed control pulse with a duty ratio of 3 / 5.

[0209] [Details of rate adjustment control: Rate adjustment control when the power supply circuit starts up from a stopped state] FIG. 25 is a timing chart showing an example of rate adjustment control when the power supply circuit starts to start up from a stopped state.

[0210] As described above, the power supply circuit 60 is activated by the motion of the permanent magnet 41, generating electricity, and then the rate adjustment means 40 performs rate adjustment control. Therefore, it is preferable that the output of the reference signal OS used for rate adjustment control be started after the power supply circuit 60 is activated. For example, as shown in FIG. 25, the output of the reference signal OS is started starting from the timing when the detection signal DE is first detected. FIG. 25 shows that the peak of the back electromotive force gradually increases, and the output of the reference signal OS is started starting from the timing when the threshold value Vth is first exceeded. In other words, the output of the reference signal OS is started from the timing (one second after) the timing when the threshold value Vth is first exceeded. However, this is not limited to this. Taking into account the unstable rotation state immediately after the power supply circuit 60 is activated, the output of the reference signal OS may be started starting from the timing when the detection signal DE is detected multiple times (a predetermined number of times).

[0211] [Details of rate adjustment control: Rate adjustment control taking into account the effects of disturbances] Fig. 26 is a timing chart showing an example of rate adjustment control taking into account the influence of disturbances. Fig. 27 is a flowchart showing an example of rate adjustment control taking into account the influence of disturbances. Fig. 28 is a flowchart showing rate adjustment control taking into account the influence of disturbances in a first modified example of the rate adjustment control shown in Fig. 20.

[0212] If an external magnet comes close to the mechanical timepiece 1 or an impact is applied to it, the back electromotive force may be disturbed momentarily due to the external disturbance, and the detection signal DE may not be detected. In this case, the control circuit 44 may erroneously determine that the watch has lost a significant amount of time.

[0213] Therefore, as shown in FIG. 26, if the detection signal DE is not detected during a predetermined period, including before and after the output period of the reference signal OS, rate adjustment may not be performed. The upper part of FIG. 26 shows a situation in which the detection signal DE is not detected near the measurement time of 2.0 [s] due to the action of an external disturbance. Specifically, the figure shows a situation in which the detection signal DE is not detected during the output period ts of the reference signal OS, the period dt1 immediately before the output period ts, and the period dt2 immediately after the output period ts. Note that while FIG. 26 shows an example in which the periods dt1 and dt2 are the same length, they may be of different lengths. Furthermore, it is preferable to output the speed control pulse while avoiding the periods dt1 and dt2. This is because outputting the speed control pulse may disrupt the coil waveform (the waveform of the back electromotive force), potentially reducing the detection accuracy of the detection signal DE.

[0214] The flowchart shown in Fig. 27 shows an example in which rate adjustment is performed when a detection signal DE is output (detected) within a predetermined detection period (dt1 to ts to dt2) (Y in step ST11) after the power supply circuit 60 is started up due to power generation caused by the movement of the permanent magnet 41 (Y in ST1). On the other hand, this flowchart shows an example in which rate adjustment is not performed when a detection signal DE is not output (detected) within the predetermined detection period (dt1 to ts to dt2) (N in step ST11). Note that each step shown in Fig. 27 is the same as that shown in Fig. 16 except for ST11, and therefore detailed explanations thereof will be omitted.

[0215] 28 shows an example in which rate adjustment is performed when the detection signal DE is output (detected) within a predetermined detection period (dt1 to ts to dt2) (Y in step ST11) after the power supply circuit 60 is started due to power generation caused by the movement of the permanent magnet 41 (Y in ST1). On the other hand, if the detection signal DE is not output (detected) within the predetermined detection period (dt1 to ts to dt2) (N in step ST11), rate adjustment is not performed and the first counter is reset (ST12). In this way, when there is an influence of a disturbance or the like, the first counter is reset, and counting the number of times the detection signal DE has been detected is restarted.

[0216] Note that the steps shown in FIG. 28 are the same as those shown in FIG. 20 except for ST11 and ST12, and the function of the first counter is also the same, so detailed explanations thereof will be omitted.

[0217] 26 to 28, it is possible to perform highly accurate rate adjustment even when disturbances are present. In addition, it is possible to prevent unnecessary output of speed control pulses, thereby reducing power consumption.

[0218] [Details of rate adjustment control: Rate adjustment control when detection of the detection signal fails repeatedly] Figures 29 and 30 are timing charts showing an example of rate adjustment control when detection of a detection signal fails repeatedly, and Figure 31 is a flowchart showing an example of rate adjustment control assuming that detection of a detection signal fails repeatedly.

[0219] As the power spring 11 unwinds, the torque of the rotor 41 weakens, and the back electromotive force may not exceed the threshold Vth. In this case, the amount of power generated decreases, and the amount of charge stored in the capacitor C also decreases. In other words, the mechanical timepiece 1 is in a state where it is likely to stop, and the power supply circuit 60 is also in a state where it is likely to stop. In such a case, in order to save power, it is preferable not to output a speed control pulse. In other words, it is preferable not to adjust the rate.

[0220] Therefore, in the examples shown in Figures 29 and 30, a configuration is adopted in which a third counter that counts the number of consecutive failures in detecting the detection signal DE and a fourth counter that counts the number of consecutive successes in detecting the detection signal DE are used to switch between a "speed control pulse output setting" that outputs speed control pulses and a "speed control pulse stop setting" that stops the output of speed control pulses.

[0221] Specifically, when the third counter reaches 10, i.e., when the detection signal DE fails to be detected 10 times in a row, the setting is switched to the speed control pulse stop setting. Also, when the fourth counter reaches 20, i.e., when the detection signal DE is successfully detected 20 times in a row, the setting is switched to the speed control pulse output setting. Note that the count number that triggers the setting switch is an example and is not limited to the one shown here.

[0222] FIG. 29 shows an example in which the peak of the back electromotive force is small and detection of the detection signal DE fails 10 times in succession, causing the setting to be switched to stop the speed-control pulse.

[0223] 30 shows an example in which the speed control pulse p1 is output by switching to the speed control pulse stop setting after 10 consecutive failed attempts to detect the detection signal DE, and then switching to the speed control pulse output setting after 20 consecutive successful attempts to detect the detection signal DE. Whether or not the detection signal DE is successfully detected is determined by whether or not the detection signal DE is output (detected) during a predetermined detection period (dt1-ts-dt2), similar to the examples shown in FIGS.

[0224] 31, after the power supply circuit 60 is started (Y in ST1) by power generation caused by the movement of the permanent magnet 41, it is determined whether or not the speed control pulse stop setting is in progress (ST41). Note that whether or not the speed control pulse stop setting is in progress may be determined, for example, based on whether or not a speed control pulse stop flag is set.

[0225] If the speed control pulse stop setting is not in progress (N in ST41), the control circuit 44 determines whether the third counter is 10 or not (ST42). That is, the control circuit 44 determines whether detection of the detection signal DE has failed 10 times in a row. If the third counter is not 10 (N in ST42), the control circuit 44 determines whether the first counter is 8 or not (ST21). That is, the control circuit 44 determines whether the number of times the detection signal DE has been detected is 8 or not.

[0226] If the first counter is 8 (Y in ST21), the process from ST24 onwards shown in Fig. 20 is carried out. On the other hand, if the first counter is not 8 (N in ST21), the control circuit 44 determines whether or not the detection signal DE is output (detected) during the predetermined detection period (dt1 to ts to dt2) (ST43). If the detection signal DE is not output (detected) during the predetermined detection period (dt1 to ts to dt2) (N in ST43), the third counter is incremented by 1 (ST44), and the first counter is incremented by 1 (ST23). On the other hand, if the detection signal DE is output (detected) during the predetermined detection period (dt1 to ts to dt2) (Y in ST43), the third counter is reset (ST45), and the period difference between the detection signal DE and the reference signal OS is calculated and accumulated (ST22).

[0227] Furthermore, if the speed control pulse stop setting is in progress in ST41 (Y in ST41), the control circuit 44 determines whether the count of the fourth counter is 20 or not (ST51). That is, the control circuit 44 determines whether the detection signal DE has been successfully detected 20 times in a row. If the fourth counter is not 20 (N in ST51), the control circuit 44 determines whether the detection signal DE has been output (detected) within a predetermined detection period (dt1 to ts to dt2) (ST52). If the detection signal DE has not been output (detected) within the predetermined detection period (dt1 to ts to dt2) (N in ST52), the control circuit 44 resets the fourth counter (ST53). If the detection signal DE has been output (detected) within the predetermined detection period (dt1 to ts to dt2) (Y in ST52), the control circuit 44 increments the count of the fourth counter by 1 (ST54).

[0228] If the count number of the fourth counter is 20 in ST51 (Y in ST51), the fourth counter is reset (ST55) and the setting is switched to the speed control pulse output setting (ST56).

[0229] Furthermore, if the count of the third counter is 10 in ST42 (Y in ST42), the third counter is reset (ST61) and the setting is switched to the speed control pulse stop setting (ST62). When the power supply circuit 60 starts operating after being stopped, the amount of charge stored in the capacitor C is low, making it likely that the power supply circuit 60 will stop again. Therefore, when the power supply circuit 60 starts operating after being stopped, it is advisable to increase the number of consecutive successful detection signals DE required before rate adjustment can be started. For example, in ST51 of FIG. 31, when the count of the fourth counter is 60, i.e., when the detection signal DE is successfully detected 60 times in a row, the setting is switched to the speed control pulse output setting.

[0230] In the examples of Figures 29 to 31 described above, by restricting rate adjustment, it is possible to reduce power consumption and, further, to easily transition to rate adjustment immediately when power spring 11 is wound up.

[0231] 29 to 31, if a back electromotive force exceeding the threshold Vth is not detected for a predetermined number of consecutive seconds, the mechanical timepiece 1 may have a function to notify the user that the mechanical timepiece 1 is in a state where it is likely to stop. For example, the position indicated by the hands may be used as a means of notification. This can prompt the user to wind up the power spring 11.

[0232] 29 to 31, if a back electromotive force exceeding the threshold Vth is not detected for a predetermined number of consecutive seconds, the threshold voltage may be lowered. Specifically, for example, if the threshold Vth is 0.5 V and detection of the detection signal DE fails 10 times in a row, the threshold voltage may be set to 0.25 V. This may make the power supply circuit 60 more likely to stop, but may maintain the accuracy of the rate. Then, after lowering the threshold Vth, if a back electromotive force exceeding the lowered threshold is detected for a predetermined number of consecutive seconds, the original threshold Vth may be restored. Furthermore, if a back electromotive force exceeding the threshold Vth is not detected for a predetermined number of consecutive seconds, the threshold may be lowered in stages.

[0233] [Details of rate adjustment control: Rate adjustment control taking into account the direction of rotation of the balance wheel] 32 is a timing chart showing an example of the output timing of the reference signal. Due to manufacturing variations during assembly of the mechanical timepiece 1, or due to position adjustment of the balance wheel 31 using the support member 33 during shipping inspection, the rotation angle of the balance wheel 31 may differ between the forward and reverse directions. If the rotation angle differs, the timing at which the detection signal DE is detected in the forward and reverse directions will differ. This may result in unnecessary output of a speed control pulse, even though there is no overall rate deviation.

[0234] Therefore, in the example shown in FIG. 32, a configuration is adopted in which the reference signal OS is set on a two-step (2-second) basis. The upper part of FIG. 32 shows an example of a back electromotive force waveform when the detection signal DE detected in the forward direction is different from that in the reverse direction. The lower part of FIG. 32 shows an example of a timing chart when the reference signal OS is set on a two-step (2-second) basis. As shown in the lower part of FIG. 32, the output interval of the odd-numbered reference signal OS from the left is set to tr1, and the output interval of the even-numbered reference signal OS from the left is set to tr2 (= tr1). This example can be realized by the control circuit 44 performing two-system control in two-step (2-second) units. If a rate abnormality is detected in either of the control systems, a rate adjustment can be performed. Note that, to simplify the circuit configuration, only one control system with an output interval of either tr1 or tr2 may be used.

[0235] In the example shown in FIG. 32, the reference signal OS is set to a two-step standard (tr1 and tr2) and rate adjustment is performed according to each step, so that even if there is a difference between the forward and reverse rotation angles of the balance wheel 31, the circuit is less likely to stop due to disturbances and highly accurate rate adjustment is possible.

[0236] The middle part of Fig. 32 shows a timing chart for the case where the reference signal OS is set on a one-step (one-second) basis, i.e., the example shown in Fig. 17 and other figures. In the example shown in the middle part of Fig. 32, the peak positions of the back electromotive force are different in the forward and reverse directions, so even though there is no rate deviation overall, the output timing of even-numbered detection signals DE from the left is always off. In such cases, speed control pulses are output unnecessarily.

[0237] [summary] In this embodiment, a configuration is adopted in which the angular velocity of the balance wheel 31 is slowed, thereby suppressing wear on each mechanism that transmits power (e.g., the escape wheel 21 and the anchor 22). As a result, the durability of the mechanical timepiece 1 is improved. Furthermore, a configuration is adopted in which the air resistance member 15 is used to slow the angular velocity of the balance wheel 31 during the intermediate periods of the balance wheel's forward and reverse motions. This allows for a sufficient amount of power to be generated by slowing the rotation period of the balance wheel 31 while generating power during periods when the balance wheel 31 is not subjected to air resistance from the air resistance member 15. Furthermore, by performing rate adjustment during or after the period when the balance wheel 31 is subjected to air resistance from the air resistance member 15, the accuracy of rate adjustment can be maintained. Furthermore, a configuration is adopted in which the permanent magnet 41 is positioned to generate a back electromotive force suitable for half-wave rectification, allowing for efficient power extraction using half-wave rectification.

[0238] [others] The rate adjustment means 40 obtains a detection signal based on the operation of the two-pole magnetized permanent magnet 41, and there is a possibility that the detection accuracy will decrease if there are any members that have a magnetic effect around the permanent magnet 41. For this reason, it is advisable to use materials that have little magnetic effect as the members around the permanent magnet 41.

[0239] For example, a resin material may be used as the material for the support member 33 and the hairpin holder 34. Phosphor bronze may be used as the material for the fastener 33a that secures the support member 33 to the main plate 10. A resin material or aluminum may be used as the material for the balance wheel 31. An acrylic resin may be used as the air resistance member 15. Note that the materials listed here are merely examples and are not intended to be limiting.

[0240] Furthermore, as described above, by making the hairspring 32 out of resin in order to reduce the Young's modulus, the magnetic influence on the permanent magnet 41 can be reduced compared to when the hairspring 32 is made of metal. Furthermore, if the hairspring 32 is made of a magnetic metal, it may be magnetically influenced by the permanent magnet 41, causing the shape and orientation of the hairspring 32 to be distorted. In this embodiment, by making the hairspring 32 out of resin, the shape and orientation of the hairspring 32 itself can be stabilized. Furthermore, a separate magnetic shield made of a magnetic material may be provided in the mechanical timepiece 1. This prevents the forward and reverse rotational motion of the permanent magnet 41 (balance wheel 31) from being disrupted, even when an external magnet approaches the mechanical timepiece 1, allowing for stable rate adjustment.

[0241] In addition, in the present embodiment, as shown in FIG. 5, an example has been shown 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, but this is not limiting. For example, the first welded portion 423 and the second welded portion 424 may not be provided, and the first end 421a and the second end 422a may be magnetically decoupled via a gap. Furthermore, the present invention is not limited to a configuration in which the magnetic coupling is completely decoupled. For example, the first end 421a and the second end 422a may be physically connected via a narrowed portion that is a separating portion.

[0242] Furthermore, although not shown, the mechanical timepiece 1 may have an opening or transparent portion on the dial or back cover that allows the balance wheel 31 to be seen from the outside.

[0243] Furthermore, in the present embodiment, an example in which the air resistance member 15 is provided has been described, but this is not limiting, and the air resistance member 15 may not be provided. Furthermore, if the air resistance member 15 is not provided, the balance wheel 31 may not have the acted upon portion 313.

[0244] When a configuration is adopted in which air resistance is applied to the balance wheel 31 using the air resistance member 15, as in this embodiment, the duration of the power spring 11 is shortened by the amount of energy consumed by the air resistance. On the other hand, in this embodiment, a resin material with a low Young's modulus is used as the material for the hairspring 32, slowing down the movement of the balance wheel 31, resulting in a longer duration compared to conventional mechanical timepieces with 6 to 8 beats. In other words, slowing down the movement of the balance wheel 31 can compensate for the decrease in duration due to air resistance. As a result, a sufficient duration can be achieved as a mechanical timepiece. [Explanation of symbols]

[0245] 1 mechanical watch, 2 winding stem, 10 main plate, 10a positioning pin, 10b opening, 11 power spring, 12 wheel train, 122 center wheel, 123 third wheel, 124 fourth wheel, 13 pointer shaft, 131 second hand, 15 air resistance member, 151 first wall portion, 152 second wall portion, 153 third wall portion, 154 base, 20 escapement mechanism, 21 escape wheel, 22 anchor, 221 anchor stem, 222 rod portion, 223 first arm portion, 224 second arm portion, 30 regulating mechanism, 31 balance wheel, 311 balance stem, 312 circular portion, 313 acted portion, 315 impulse jewel, 32 balance spring, 321 outer end portion, 322 inner end portion, 322a fixed portion, 322b Pitch expansion portion, 33 support member, 33a pipe, 33b screw, 34 hairpin holder, 35 frame member, 35a convex portion, 40 rate adjustment means, 41 permanent magnet, 42 soft magnetic core, 421 first magnetic portion, 421a first end, 422 second magnetic portion, 422a second end, 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 quartz oscillator, n11, n12, n21, n22 notch.

Claims

[Claim 1] A power source and a speed-regulating mechanism including 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 bipolar permanent magnet that rotates in both directions in accordance with the rotation of the balance wheel; A coil and a soft magnetic core including a first end provided along the outer periphery of the permanent magnet and a second end provided along the outer periphery of the permanent magnet and arranged opposite the first end with the permanent magnet interposed therebetween, the soft magnetic core forming a magnetic circuit together with the coil; a control circuit 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 wheel and a reference frequency of a reference signal source; a rectifier circuit that rectifies a current generated in the coil due to the movement of the permanent magnet accompanying the forward and reverse movements of the balance wheel; a power supply circuit that drives the control circuit based on the current rectified by the rectifier circuit; and the permanent magnet is arranged such that the magnetization direction faces the first end or the second end when the hairspring is in a neutral position of its elastic deformation; Mechanical watch.

Images