Mechanical timepiece

Abstract

To efficiently take out electric power in a mechanical timepiece 1 that adjusts rate using electromagnetic means.SOLUTION: The mechanical timepiece 1 has: a balance wheel 31; a balance spring 32; a permanent magnet 41; a soft magnetic core 42; a control circuit 44 for adjusting rate on the basis of counter electromotive voltage generated in a coil 43 by motion of the permanent magnet 41 accompanying forward motion and reverse motion of the balance wheel 31, and a reference vibration-frequency of a reference signal source; a rectification circuit 50 for rectifying a current generated in the coil 43 by the motion of the permanent magnet 41 accompanying the forward motion and the reverse motion of the balance wheel 31; and a power supply circuit 60 for driving the control circuit 44 on the basis of the current rectified by the rectification circuit 50. The permanent magnet 41 is arranged so that a magnetization direction faces a side of a first end portion 421a or a second end portion 422a in a state where the balance spring 32 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 power based on the motion of a magnet attached to the axle (balance wheel) and adjusts 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 discloses a configuration in which power is generated by electricity 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] JP 2020-38206 A [Patent Document 2] JP 2019-113548 A 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 very small, some method 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 consideration of the above problems, and has an object to efficiently extract power from a mechanical timepiece that uses electromagnetic means for rate adjustment. [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 disposed opposite the first end via the permanent magnet, forming a magnetic circuit together with the coil; and a speed-regulating mechanism that regulates the forward and reverse rotation of the balance wheel. a control circuit which adjusts the rate based on a detection voltage generated in the coil by 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 which rectifies a current generated in the coil by the movement of the permanent magnet accompanying the forward and reverse movements of the balance wheel; and a power supply circuit which 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 the mechanical timepiece according to (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 according to (1) or (2), wherein 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 is arranged so that the magnetization direction is perpendicular to the opposing direction between the first separation portion and the second separation portion when the hairspring is in the neutral position.

[0009] (4) A mechanical timepiece according to (1) or (2), wherein 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, 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 the mechanical watch according to (5), the permanent magnet is arranged so that the detection 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 regulating pulse output circuit that outputs a regulating pulse to control the movement of the balance wheel, wherein the control circuit controls the 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 mechanical watch, wherein 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 according to (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) In any one of (7) to (9), 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 watch according to (9) or (10), the speed-regulating pulse output circuit outputs the speed-regulating pulse according to an amount of deviation of a detection timing of the detection signal from an output timing of the reference signal.

[0017] (12) In (11), a mechanical watch having an accumulation unit that accumulates an amount of deviation of the detection timing of the detection signal relative to 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 accumulated in the accumulation 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 with respect to a rotation axis of the balance wheel and that acts on the balance wheel during each intermediate period of the forward and reverse motions of the forward and reverse rotational motions of the balance wheel to decelerate the balance wheel, the balance wheel being formed in a portion of its circumferential direction and including a portion 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 a detection 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 according to (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 being supplied with 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 watch according to any one of (1) to (16), wherein the rectifier circuit includes one diode.

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

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

[0025] (20) The 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. Effect of the Invention

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

[0027] [Figure 1] FIG. 2 is a perspective view showing the base plate and each member assembled thereto according to the present embodiment. [Diagram 2] FIG. 2 is a perspective view showing a mechanism for transmitting power and its surroundings in the embodiment. [Diagram 3] 2 is an exploded perspective view showing the speed regulating mechanism and its peripheral members disassembled from the main plate in the embodiment. FIG. [Figure 4]2 is a diagram showing a cross section of a support member and a soft magnetic core of the present embodiment, and their surroundings. FIG. [Diagram 5] 2A and 2B are a plan view showing a soft magnetic core and its periphery according to the 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 embodiment. [Figure 7] 5 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 an air resistance member disassembled from a base plate. [Figure 10] FIG. 4 is a perspective view showing the operation of the balance wheel of the present embodiment. [Figure 11A] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11B] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11C] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11D] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11E] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11F] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11G] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11H] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11I] FIG. 11 is a perspective view showing a balance wheel and an air resistance member in a modified example of the embodiment. [Figure 11J] FIG. 11 is a perspective view showing a balance wheel and an elastic member in a modified example of the embodiment. [Figure 11K]FIG. 11 is a perspective view showing another example of a balance wheel as viewed from the side where the hairspring is provided. [Figure 11L] 11K 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. 4 is a plan view showing a state in which the hairspring is in a neutral position of its elastic deformation. [Figure 11N] 1 is a plan view showing a state in which the hairspring is elastically deformed in an expanding direction from a neutral position. FIG. [Figure 11O] 1 is a plan view showing a state in which the hairspring is elastically deformed in a contracting direction from a neutral position. FIG. [Figure 12] 5A and 5B are diagrams illustrating the relationship between the operation of the balance wheel and the back electromotive voltage generated in the coil in the embodiment. [Figure 13A] FIG. 4 is a diagram showing a back electromotive force detected by a coil in the arrangement of permanent magnets according to the present embodiment. [Figure 13B] FIG. 13 is a diagram showing a back electromotive force detected by a coil in the arrangement of permanent magnets in Comparative Example 1. [Figure 13C] FIG. 11 is a diagram showing a back electromotive force detected by a coil in the arrangement of 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. 4 is a circuit diagram showing another example of the circuit according to the embodiment. [Figure 15A] 4A to 4C are diagrams illustrating control of the movement of a permanent magnet by a speed control pulse in this embodiment. [Figure 15B] 4A to 4C are diagrams illustrating control of the movement of a permanent magnet by a speed control pulse in this embodiment. [Figure 16] 5 is a flowchart showing an example of a 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] 11 is a timing chart showing an example in which the detection timing of a detection signal is earlier than the output period of a reference signal. [Figure 19]11 is a timing chart showing an example in which the timing at which a detection signal is detected is later than the output period of a reference signal. [Figure 20] 13 is a flowchart showing a first modified example of the rate adjustment control. [Figure 21] 6 is a timing chart showing a detection signal and a reference signal in a first modified example of rate adjustment control. [Figure 22] 13 is a flowchart showing a second modified example of the rate adjustment control. [Diagram 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. 4 is a diagram showing an example of a speed control pulse. [Diagram 25] 4 is a timing chart showing an example of a rate adjustment control when a power supply circuit starts to start up from a stopped state. [Figure 26] 5 is a timing chart showing an example of rate adjustment control taking into account the influence of disturbances. [Figure 27] 5 is a flowchart showing an example of a rate adjustment control taking into consideration the influence of disturbance. [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 failure to detect a detection signal occurs successively. [Diagram 30] 10 is a timing chart showing an example of rate adjustment control when failure to detect a detection signal occurs successively. [Diagram 31] 10 is a flowchart showing an example of rate adjustment control assuming that detection failures of a detection signal occur consecutively. [Diagram 32] 4 is a timing chart showing an example of output timing of a reference signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 described 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 mechanism for transmitting power and its periphery in this embodiment. Fig. 3 is an exploded perspective view showing the speed regulating mechanism and its peripheral 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 disposed.

[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 part 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 in this embodiment. FIG. 8 is a block diagram showing the overall configuration of the mechanical timepiece according to 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 of the mechanical timepiece 1 in the thickness direction 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 positive direction, and the clockwise direction is defined as the negative 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 assembled, in an exterior case. Note that in this embodiment, the exterior case is not shown in the figure. Also, the crown that is placed on the side of the exterior case is not shown in the figure. 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 be described. In this embodiment, the mechanism including the power spring 11, which is the power source, the wheel train 12, and the hand shaft 13 is referred to as the "drive mechanism." Note that in Fig. 2, only the second hand 131 of the hands is shown. The drive mechanism shown in Fig. 2 is one example, and is not limited to this, and may include gears and the like other than those shown in the figure.

[0034] The power spring 11 is made of a metal band-shaped body and is housed in a barrel 110 having a plurality of teeth formed on its outer circumference. The barrel 110 is disk-shaped and has a cavity formed therein for housing the power spring 11. The inner end of the power spring 11 is fixed to a barrel stem (not shown) which is a rotating shaft provided at the center of the barrel 110, and the outer end is fixed to the inner surface of the barrel 110. When the crown is rotated by a user's operation, the winding stem 2 rotates. The power spring 11 is wound up in accordance with the rotation of the winding stem 2. The wound power spring 11 is unwound by its elastic force. The operation of the power spring 11 at this time causes the barrel 110 to rotate.

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

[0036] [Overview of the overall configuration: Overview of the configuration of the escapement mechanism 20 and the speed regulator mechanism 30, and their operation] Next, the escapement mechanism 20 and the regulating mechanism 30 will be described. Power from the power spring 11 is transmitted to the escapement mechanism 20 and the regulating mechanism 30 through 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 receives the rhythm of the regulating mechanism 30 from the pallet fork 22 by meshing with the pallet fork 22 and converts it into regular 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 Figure 2, the multiple teeth of the escape wheel 21 are formed at wider intervals in the circumferential direction than the teeth of each gear of the train wheel 12.

[0038] The pallet fork 22 rotates forward and backward around the pallet fork arbor 221 shown in Fig. 5 as a rotation axis. The pallet fork 22 extends from the pallet fork arbor 221 toward the center of the balance wheel 31 (balance arbour 311) and has a rod portion 222 that strikes an impulse jewel 315 (see Fig. 6) that rotates together with the balance arbour 311. The impulse jewel 315 is fixed to a disk-shaped portion of the balance arbour 311 that has a predetermined width in the radial direction. Fig. 6 shows the balance wheel 31 rotated 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 a recessed prong 223a that strikes against multiple teeth of the escape wheel 21, and a second arm 224 to which is attached a projecting prong 224a that extends in the opposite direction to the first arm 223 and strikes against multiple teeth of the escape wheel 21. The recessed prong 223a and the projecting prong 224a may be made of a stone such as sapphire.

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

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

[0042] The escape wheel 21 rotates with the rotation of the fourth wheel 124. When the escape wheel 21 rotates, it collides with the pallet 223a of the pallet fork 22, and the pallet fork 22 rotates around the pallet fork arbor 221. The rod portion 222 of the rotating pallet fork 22 collides with the impulse jewel 315 fixed to the balance arbor 311, causing the balance wheel 31 to rotate. When the balance wheel 31 rotates, the pallet 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 223a of the pallet fork 22 is released, and the escape wheel 21 rotates again. As described later, the balance wheel 31 is designed to perform one cycle of operation in two seconds, so that the escape wheel 21 performs one step of operation per second.

[0043] As described above, the regulating mechanism 30 repeatedly rotates the balance wheel 31 in forward and reverse directions (reciprocating motion) at a constant cycle by the expansion and contraction motion of the hairspring 32. The escapement mechanism 20 continues to apply a force for reciprocating motion to the balance wheel 31. With this configuration and operation, the hands such as the second hand 131 are driven.

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

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

[0046] Although not shown in the drawings, the coil 43 may be arranged so as to overlap an inner frame provided inside the outer case in a plan view. Alternatively, a notch may be formed in a part of the inner frame in the circumferential direction, and the coil 43 may be arranged within the notch.

[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.

[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 perform forward and reverse rotational motion in accordance with the forward and reverse rotational motion of the balance wheel 31 (balance stem 311). In other words, the permanent magnet 41 performs forward and reverse rotational motion 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 may be fixed to the balance stem 311 by press-fitting, adhesive, or the like.

[0049] The permanent magnet 41 is preferably an isotropic magnet with its easy axis of magnetization pointing in a random direction. The permanent magnet 41 is preferably magnetized by applying a magnetic field to it using a Helmholtz coil or the like while attached to the balance shaft 311. By employing such a magnetization method, the magnetization direction of the permanent magnet 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 inner circumferential surface, and are disposed 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 permanent magnet 41 has the N-pole portion 411 disposed on the second magnetic portion 422 side and the S-pole portion 412 disposed on the first magnetic portion 421 side (see the enlarged view of 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 convex portion 35a. The convex portion 35a is fitted to the inner peripheral surface of the first end portion 421a and the second end portion 422a of the soft magnetic core 42. The soft magnetic core 42 is positioned at two points, the frame member 35 and the positioning pin 10a. With this configuration, the soft magnetic core 42 can be assembled to the base plate 10 with good positional accuracy. As a result, the positional accuracy of the soft magnetic core 42 relative to the permanent magnet 41 can be improved. Here, the soft magnetic core 42 is made of a magnetic material, and the magnetic properties may deteriorate when a strong stress is applied. For example, if the soft magnetic core 42 is directly fastened to the base plate 10 by a screw or the like, the magnetic properties may deteriorate. Therefore, in this embodiment, the fitting of the positioning pin 10a and the frame member 35 is performed as a clearance fit, and the soft magnetic core 42 is fixed to the support member 33 by the pipe 33a and the screw 33b, thereby achieving both positioning and fixing of the soft magnetic core 42. By adopting such a configuration, it is possible to improve the positional accuracy of the soft magnetic core 42 without deteriorating the magnetic characteristics of the soft magnetic core 42. Also, in this embodiment, the soft magnetic core 42 is arranged to be fixed to the support member 33, but a configuration may be adopted in which the permanent magnet 41 corresponding to the soft magnetic core 42 is arranged between the balance wheel 31 and the main plate 10, and the soft magnetic core 42 is directly fastened to the main plate 10 by 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 located close to the permanent magnet 41, excluding the soft magnetic core 42, are desirably made of non-magnetic materials so as not to affect the forward and reverse rotational motion of the regulating mechanism 30 or the back electromotive force generated by the coil 43 described later.

[0055] 5, the soft magnetic core 42 includes a first welded portion 423 which is a first separation portion 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 separation portion 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 the 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 set to a rotation angle of 0°. In this position, the holding torque of the permanent magnet 41 is approximately 0. 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 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 thick line graph in Fig. 7 shows 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, a notch n11 and a notch n12 are formed on the first end 421a. Also, a notch n21 is formed on the second end 422a so as to face the notch n11 via the permanent magnet 41, and a notch n22 is formed so as to face the notch n12 via the permanent magnet 41. By forming the notches in this manner, the magnetic influence that the permanent magnet 41 receives from the soft magnetic core 42 is reduced. Therefore, the holding torque of the permanent magnet 41 can be reduced.

[0059] One dashed line graph in FIG. 7 shows the holding torque of the permanent magnet 41 resulting from 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 resulting from 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 above-mentioned three broken 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 in the soft magnetic core 42. As shown in FIG. 7, in the configuration of this embodiment, the holding torques shown in the broken line graphs cancel each other out at each rotation angle, and the composite holding torque of the permanent magnet 41 is close to 0 at any rotation angle. Therefore, even if a hairspring 32 made of a material with a low Young's modulus is used as described later, 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. It is preferable that at least a pair of mutually opposing notches that reduce the holding torque of the permanent magnet 41 are formed in the first end portion 421a and the second end portion 422a.

[0061] [Overall configuration: Overview of rate adjustment] As shown in Fig. 8, the mechanical timepiece 1 includes a rectifier circuit 50, a power supply circuit 60, and a quartz crystal oscillator 70 in addition to the power spring 11, the wheel train 12, the escapement mechanism 20, the speed control mechanism 30, and the 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 control pulse output circuit 46, a frequency divider circuit 47, and an oscillation circuit 48 in addition to the permanent magnet 41, the soft magnetic core 42, and the coil 43 described above. Note that the configuration of the rate adjustment means 40 shown in Fig. 8 is 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 can realize each function 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 oscillation circuit 48 outputs a predetermined oscillation signal based on the frequency of the crystal oscillator 70. The frequency of the crystal oscillator 70 is 32768 [Hz]. The frequency divider circuit 47 divides the frequency of the oscillation signal output from the oscillation circuit 48. The frequency divider circuit 47 divides the frequency of the oscillation signal based on the crystal oscillator 70 to generate a reference signal OS that is output approximately every 1000 [ms]. However, this is not limited, and the reference signal OS may be output every 2000 [ms] or every 3000 [ms]. In other words, the reference signal OS may be output every second. Furthermore, this is not limited, and the reference signal OS may be output corresponding to the period of the speed-governing mechanism 30.

[0064] The rotation detection circuit 45 detects a detection signal based on a voltage waveform generated in the coil 43 by the motion of the permanent magnet 41. The speed control pulse output circuit 46 outputs a speed control pulse based on a reference signal generated by a frequency division circuit 47 and a 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 a reference signal of about 1000 [Hz], and if there is a discrepancy between these timings, the speed control pulse output circuit 46 outputs a speed control pulse so as to bring the period at which the detection signal is detected closer to 1000 [ms] (=1 second).

[0065] The speed control pulse is output by energizing the coil 43. Therefore, when the period in 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 a torque acts in a direction that retards the movement of the permanent magnet 41, and when the period in which the detection signal is detected is slower than the reference signal, the speed control pulse output circuit 46 energizes the coil 43 so that a torque acts in a direction that accelerates 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] [Overall configuration: Governor 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 speed-regulating mechanism 30 functions as part of the generator. Specifically, the permanent magnet 41 rotates forward and backward in accordance with the forward and reverse rotation of the balance wheel 31, and power is generated by the current generated in the coil 43 based on the change in the magnetic field caused by the movement of the permanent magnet 41. The power extracted by this operating principle is used to start the power supply circuit 60. The start of the power supply circuit 60 makes it possible to drive the control circuit 44 included in the rate adjustment means 40. Because this configuration is adopted, in this embodiment, the control circuit 44 can be driven without providing a separate power source such as a battery.

[0067] The rectifier circuit 50 rectifies the current generated in the coil 43 by the motion of the permanent magnet 41 associated with the forward and reverse rotational motions of the balance wheel of the speed regulating mechanism 30. The power supply circuit 60 is a circuit including, for example, a capacitor, and stores power for driving the control circuit 44 based on the current rectified by the rectifier circuit 50.

[0068] [About slowing down the balance wheel 31] Here, in the mechanical timepiece 1, the faster the movement of the balance wheel 31, i.e., the faster the operation cycle of the balance wheel 31, the more easily the mechanisms that transmit power (e.g., the escape wheel 21 and the anchor 22) wear out, and the durability decreases. On the other hand, since the amount of current generated in the coil 43 is proportional to the angular velocity of the permanent magnet 41, if the movement of the balance wheel 31 is slow, the amount of power generation required 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 while ensuring a sufficient amount of power generation.

[0070] FIG. 10 is a perspective view showing the operation of the balance wheel of this embodiment. FIG. 10 shows the balance wheel 31, the anchor 22, the permanent magnet 41, and the air resistance member 15 described later. In FIG. 10, the reference numerals are omitted except for the figure showing the state of the rotation angle of 0°. FIG. 12 is a diagram explaining the relationship between the operation of the balance wheel in this embodiment and the back electromotive force generated in the coil. In the graph in the upper part of FIG. 12, the vertical axis is the angular velocity [rad / s] of the balance wheel 31, and the horizontal axis is the measurement time [s]. In the graph in the middle part of FIG. 12, the vertical axis is the rotation angle [deg] of the balance wheel 31, and the horizontal axis is the measurement time [s]. In the graph in the lower part of FIG. 12, the vertical axis is the back electromotive force [V] generated in the coil 43, and the horizontal axis is the measurement time [s]. In addition, each graph shown in FIG. 12 shows an example in which the movement of the balance wheel 31 (permanent magnet 41) was measured for 4 seconds.

[0071] In this embodiment, the balance wheel 31 is designed to perform one reciprocating motion in two seconds. For this purpose, a resin material with a low Young's modulus is used as the material for the hairspring 32. This allows the balance wheel 31 to oscillate at a slower speed than when it is made of a metal material. If one were to attempt to achieve slower oscillations with a metal hairspring, it would be necessary to reduce the cross-sectional area of ​​the hairspring 32 to a level that makes it difficult to process, or to increase the length of the hairspring to a level that makes it difficult to handle.

[0072] In this embodiment, a resin having a Young's modulus of about 5 [GPa] is used as the material of the hairspring 32. Specifically, polyester is used as the material of the hairspring 32. The hairspring 32 made of a resin material may be manufactured by, for example, laser processing. The Young's modulus of a general metal hairspring is about 200 [GPa]. The Young's modulus shown here is an example, and the Young's modulus of the hairspring 32 may be 20 [GPa] or less. That is, the Young's modulus of the hairspring 32 may be 1 / 10 or less of the Young's modulus of the metal hairspring. More preferably, the Young's modulus of the hairspring 32 may be 10 [GPa] or less. That is, the Young's modulus of the hairspring 32 may be 1 / 20 or less of the Young's modulus of the metal hairspring. Also, the Young's modulus may be 20 [GPa] or less, and the hairspring 3 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 in a state where the hairspring 32 is in a neutral position of elastic deformation is set to 0°. The neutral position of elastic deformation of the hairspring 32 is, in other words, a position where the hairspring 32 is at its natural length. Power is supplied from the power spring 11 to the balance wheel 31 in a state where the hairspring 32 is in a neutral position of 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 at a rotation angle of 0°. As described above, in this embodiment, the permanent magnet 41 is in a magnetically balanced position at a rotation angle of 0°.

[0074] 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 only an example, and the movement range of the balance wheel 31 is preferably equal to or greater than the range of rotation angles of 270° to -270°. Increasing the movement range of the balance wheel 31 to a certain extent in this way makes it possible to achieve low-speed vibration of the balance wheel 31.

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

[0076] [Slowing down the balance wheel 31: Air resistance component 15] Furthermore, in this embodiment, the air resistance member 15, which is the deceleration means, is attached to the main plate 10, and a configuration is adopted in which an acted upon portion 313 that receives air resistance from the air resistance member 15 is formed on a portion of the balance wheel 31 in the circumferential direction. 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 in both directions around a balance arbour 311, and an acted part 313 that protrudes in the radial direction from a part of the circumferential direction of the circular part 312. In this embodiment, the acted part 313 is the part of the balance wheel 31 that has the longest radial length. In this embodiment, the acted part 313 has a sector shape as shown in Fig. 10 .

[0078] The air resistance member 15 has a resistance wall that forms 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 part 313 of the balance wheel 31, a second wall portion 152 that faces the other surface of the acted part 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 walls 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 part of the main plate 10, the air resistance member 15 is fitted into the opening 10b, and the base 154 is fixed to the main plate 10 by a fastener such as a bolt. The air resistance member 15 may be fitted into the opening 10b from the side of the main plate 10 opposite to the side where the drive mechanism, the escapement mechanism 20, the speed regulating mechanism 30, etc. are assembled. That is, the base 154 may be fixed to the surface of the main plate 10 opposite to the side where the drive mechanism, the escapement mechanism 20, the speed regulating mechanism 30, etc. are assembled. Note that FIG. 9 shows an example in which the opening 10b is formed in a part of the main plate 10, but this is not limiting and any hole penetrating from one side of the main plate 10 to the other side 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 upon portion 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 upon portion 313 of the balance wheel 31 experiences air resistance when the rotation angle of the balance wheel 31 is between 135° and 225°, and the angular velocity decreases. Similarly, although not shown, the acted upon portion 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), and the angular velocity decreases.

[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 Fig. 12 at a timing before the measurement time reaches 2.0 seconds, the angular velocity of the balance wheel 31 increases rapidly from the position where the balance wheel 31 has a rotation angle of 0°, and reaches a peak at a 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. After that, the balance wheel 31 rotates in the reverse direction from the rotation angle of 340° in accordance with the elastic deformation of the hairspring 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 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 in the reverse direction from a rotation angle of 340° to a rotation angle of 0°.

[0085] Then, the balance wheel 31 returns to the position of a rotation angle of 0°, and receives power from the power spring 11, and the angular velocity in the reverse direction increases rapidly and reaches 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). After that, 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, since the balance wheel 31 includes the acted part 313 that protrudes in the radial direction, the position of the center of gravity of the balance wheel 31 is closer to the acted part 313 side than the balance arbour 311 (center of rotation). In a configuration in which the position of the center of gravity is shifted from the balance arbour 311 at the center position of the balance wheel 31, the rotational movement of the balance wheel 31 becomes unstable. Therefore, in this embodiment, an opening 312h is formed in a part of the circular part 312 so that the position of 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 so as to be adjacent to the acted part 313 in the circumferential direction. By adopting such a configuration, the rotational movement 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 disposed so that the acted upon 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 disposed so that its center position 15C (see FIG. 6) in the circumferential direction 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 received by the acted upon 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, with reference to Fig. 11A to Fig. 11J, modified examples of the structure for reducing the angular velocity of the balance wheel 31 will be described. Fig. 11A to Fig. 11I are perspective views showing a balance wheel and an air resistance member in a modified example of this embodiment. Fig. 11J is a perspective view showing a balance wheel and an elastic member in a modified example of this embodiment.

[0089] The balance wheel 31 shown in Fig. 11A is obtained by providing three notches 313A so as to form resistance walls intersecting in the circumferential direction in the acted part 313 of the balance wheel 31 shown in Fig. 10. 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 obtained by providing three radially extending grooves 313B so as to form resistance walls intersecting in the circumferential direction in the acted part 313 of the balance wheel 31 shown in Fig. 10. 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 provided with three through holes 313C so as to form resistance walls intersecting in the circumferential direction in the acted part 313 of the balance wheel 31 shown in Fig. 10. 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 part 313 passes through the air resistance area AR, the air flow in the air resistance area AR is disturbed, and the air resistance experienced by the acted part 313 increases. This makes it possible to slow down the speed of the acted part 313 passing through the air resistance area AR.

[0093] 11A to 11C are merely examples, and are not limited to these, as long as the shape has a recessed portion that forms a resistance wall that increases air resistance. In other words, the positions and number of notches and the like 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 orbit of the acted portion 313. That is, the air resistance member 15 forms an air resistance region AR only with the first wall portion 151 and the second wall portion 152 opposed to each other. Note that the first wall portion 151 and the second wall portion 152 may be attached to the base plate 10 etc. independently of each other.

[0095] 11D, the acted upon portion 313 protrudes radially inward. Therefore, the acted upon portion 313 passes through the air resistance area AR with the rotational motion 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 upon 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 upon portion 313 can pass through the air resistance area AR.

[0097] 11E, in FIG. 11F, the acted upon portion 313 is provided at a position different 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 where the acted upon portion 313 can pass through the air resistance area AR in the axial direction of the balance arbour 311. 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 example 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 of the position facing the acted portion 313 via the balance arbour 311 is thicker. That is, the weight of the circular portion 312 is greater at the position facing the acted portion 313 via 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 smaller 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 and second wall portion 152, but only includes a configuration corresponding to third wall portion 153. That is, air resistance member 15 in FIG. 11H is composed 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] Fig. 11I shows an example in which grooves 153I, which are recesses forming 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 passing 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) instead of air resistance. Specifically, the balance wheel 31 has a protrusion 316 formed on a 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°. It is preferable that the first elastic member 151J and the second elastic member 152J have their ends fixed to the main plate 10.

[0104] The first elastic member 151J and the second elastic member 152J are elastically deformed while generating frictional resistance between the protrusion 316 of the balance wheel 31 and the first elastic member 151J and the second elastic member 152J when the protrusion 316 of the balance wheel 31 comes into contact with the first elastic member 151J and the second elastic member 152J. The speed of the balance wheel 31 is decelerated by the frictional resistance while the balance wheel 31 is in contact with the protrusion 316. In the example shown in Fig. 11J, the region where 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 just 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 sufficient, and is not limited to the examples shown.

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

[0107] 11K and 11L, similar to that shown in Fig. 10 etc., has a circular part 312 and an acted part 313. Further, an opening 312h is formed in the circular part 312 at a position overlapping with the acted part 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 part of the circular portion 312 on the inside of the edge 312a. The acted upon portion 313 is formed flush with the edge 312a. That is, the thickness of the acted upon portion 313 is the same as that of the edge 312a, and is thicker than the part of the circular portion 312 on the inside of the edge 312a.

[0109] 11K and 11L, the acted part 313 has a relatively large thickness, and therefore the surface of the acted part 313 that receives air resistance is relatively large. This increases the amount of air pushed aside by the acted part 313 within the air resistance area AR shown in Fig. 10, making it easier to hinder the movement of the balance wheel 31 and to make it easier to slow down the balance wheel 31. In addition, since the hairspring 32 is disposed on a relatively thin part of the balance wheel 31 other than the edge part 312a and the acted part 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 part 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 part 313 is increased, the weight of the acted part 313 increases, and the center of gravity of the balance wheel 31 moves closer to the acted part 313 side. However, by partially increasing the thickness of the circular part 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] Further, the balance spring 32 will be described in detail with reference to Fig. 11M to Fig. 11O. Fig. 11M is a plan view showing a state in which the balance spring is in a neutral position for its elastic deformation. Fig. 11N is a plan view showing a state in which the balance spring has elastically deformed in an expanding direction from the neutral position. Fig. 11O is a plan view showing a state in which the balance spring has elastically deformed in a contracting 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 fits along the circumferential surface of the balance axle 311. The outer end 321 and the inner end 322 are thicker than other portions (portions that undergo elastic deformation) of the hairspring 32. Therefore, the strength of the connections to the hairspring holder 34 and the balance axle 311 is maintained.

[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, if the overall length of the hairspring 32 is increased, the diameter of the hairspring 32 increases. 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 parts of the hairspring 32. In other words, it is advisable to narrow the pitch of the hairspring 32.

[0114] A logarithmic spiral shape is adopted for the hairspring 32. As described above, a logarithmic spiral hairspring can be easily manufactured by performing 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 that is used as a general hairspring shape, and the overall length of the hairspring can be increased and the diameter can be reduced. As a result, the spring force can be reduced with the diameter of the hairspring 32 being reduced, and low vibration can also be achieved. However, when the hairspring 32 is manufactured by laser processing as described above, it is difficult to narrow the pitch. This is because the shape of the hairspring 32 may be deformed by the heat of the laser light.

[0115] In order to narrow the pitch while maintaining the dimensional accuracy of the hairspring 32, the inner end 322 is configured to include a fixed portion 322a and a pitch enlarged 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 pitch enlarged portion 322b is a portion narrower in width than the fixed portion 322a, and is a portion that enlarges the pitch between the inner end 322 and a portion 323 of the hairspring 32 that is adjacent to the inner end 322 in the radial direction. The portion 323 of the hairspring 32 that is adjacent to the inner end 322 in the radial direction is a portion other than the inner end 322, and is the portion that is disposed on the innermost side. W shown in Figs. 11M to 11O indicates the distance between the inner end 322 and the portion 323 that is adjacent to the inner end 322 in the radial direction.

[0116] 11M to 11O show an example in which the inner end 322 is annular, that is, the fixed portion 322a and the pitch enlarged portion 322b are connected, but the present invention is not limited to this. For example, the inner end 322 may be partially separated in the circumferential direction, and the separated portion may function as the pitch enlarged portion 322b. However, the inner end 322 having an annular shape is more likely to ensure the strength of the fixation to the balance arbour 311. Although the hairspring 32 has a logarithmic spiral shape in the examples shown in FIGS. 11M to 11O, the present invention is not limited to this. The 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] [Time of power generation] The amount of current generated in the coil 43 by 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 fast.

[0118] Therefore, in this embodiment, power is generated based on a current corresponding to a back electromotive voltage (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 voltage detected by the coil 43 reaches its peak.

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

[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 magnetization direction of 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 with the rectifier circuit 50. Here, as the rectification by the rectifier circuit 50, full-wave rectification using a bridge circuit including multiple diodes, or half-wave rectification using a circuit including one diode can be considered. When multiple diodes are used, a voltage drop occurs according to the number of diodes, resulting in a loss of power obtained. Therefore, in this embodiment, a configuration is adopted in which the rectifier circuit 50 performs half-wave rectification. In addition, in half-wave rectification, a difference is made between the shape of the positive back electromotive force and the negative back electromotive force, and power is generated based on the back electromotive force with the larger absolute value, thereby enabling efficient power generation. Therefore, in this embodiment, the permanent magnet 41 is arranged so that a back electromotive force suitable for half-wave rectification is detected.

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

[0124] [Relationship between magnetization direction of permanent magnet 41 and power generation efficiency: present 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 voltage 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] Moreover, the back electromotive voltage generated in the coil 43 due to the 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 voltage. On the other hand, the back electromotive voltage generated in the coil 43 due to the 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 voltage.

[0127] In this embodiment, the permanent magnet 41 is in a magnetically balanced position at a rotation angle of 0°. Therefore, at a rotation angle of 0°, the back electromotive voltage generated in the coil 43 is zero. 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 is maximum at the timing immediately after the rotation angle of 0°. Also, 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 voltages detected in the coil 43 during the forward rotation of 180° from the power supply position are of the same polarity.

[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 voltage 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 voltage 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 portion 421a. Therefore, a negative counter electromotive voltage 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 counter electromotive voltage is smaller than the absolute value of the peak of the positive counter electromotive voltage.

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

[0134] Furthermore, the permanent magnet 41 rotates from the rotation angle 180° to 0°. When the permanent magnet 41 rotates from the rotation angle 180° to 0°, the N pole portion 411 moves in a direction away from the first end portion 421a. Therefore, when the permanent magnet 41 rotates from the rotation angle 180° to 0°, a negative counter electromotive voltage 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 voltage generated in the coil 43 becomes 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 becomes maximum immediately after the rotation angle of 0°. Also, 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 such that the back electromotive voltages detected in the coil 43 during the rotation of the permanent magnet 41 in the reverse direction from the power supply position to -180° have 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 voltage 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 voltage 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 portion 421a. Therefore, a negative counter electromotive voltage 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 counter electromotive voltage is smaller than the absolute value of the peak of the positive counter electromotive voltage.

[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 voltage 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 counter electromotive voltage is generated in the coil 43 while the permanent magnet 41 rotates from a rotation angle of -340° to -180°.

[0142] At a rotation angle of −180°, where the permanent magnet 41 is in a magnetically balanced position, the back electromotive voltage 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 portion 421a. Therefore, when the permanent magnet 41 rotates from a rotation angle of -180° to 0°, a negative counter electromotive voltage is generated in the coil 43.

[0144] By repeating the above-mentioned operation, in the arrangement of the permanent magnet 41 of this embodiment, a back electromotive voltage with a waveform shown in Fig. 13A is generated in the coil 43. As shown in Fig. 13A, the peaks of the back electromotive voltage are different between the positive back electromotive voltage and the negative back electromotive voltage. That is, the maximum absolute value of the positive back electromotive voltage is greater than the maximum absolute value of the negative back electromotive voltage. Furthermore, the waveforms of the back electromotive voltage detected when the permanent magnet 41 moves in the positive direction are the same as 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 inclined by 45° to the opposing direction of first welded part 423 and second welded part 424 when hair spring 32 is in the neutral position of its elastic deformation. That is, in comparative example 1, the position of the rotation angle of 0° is inclined by -45° from the present embodiment.

[0146] In Comparative Example 1, when the permanent magnet 41 rotates in the positive direction from a rotation angle of 0°, first, the N-pole portion 411 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 from 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 counter electromotive voltage is generated in the coil 43 immediately after the rotation, and then, after the rotation angle passes 45°, a positive counter electromotive voltage 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, returns to the rotation angle of 0° again, and when rotating in the reverse direction from the rotation angle of 0°, the N-pole portion 411 moves in a direction approaching the first end 421a. That is, when the permanent magnet 41 rotates in the reverse direction from the rotation angle of 0°, a positive counter electromotive voltage is generated in the coil 43.

[0148] Thus, in Comparative Example 1, the waveforms of the positive counter electromotive voltage and the negative counter electromotive voltage are different at least around the rotation angle of 0° in the forward and reverse directions of rotation. Therefore, the magnitude of the peak of the counter electromotive voltage is different in the forward and reverse directions of rotation. In addition, since the peak position of the counter electromotive voltage is different in the forward and reverse directions of rotation, it is determined that the period of the forward and reverse rotational motion of the balance wheel 31 is disturbed, and there is a possibility that the rate adjustment is erroneously performed. Therefore, in the configuration of Comparative Example 1, it becomes necessary for the rate adjustment means 40 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 hair spring 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 a tilt of -90° from the present embodiment.

[0150] In Comparative Example 2, when the permanent magnet 41 rotates in the positive direction from a rotation angle of 0°, first, the N-pole portion 411 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 from 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 counter electromotive voltage is generated in the coil 43 immediately after the rotation, and then, after the rotation angle passes 90°, a positive counter electromotive voltage 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, returns to the rotation angle of 0° again, and when rotating 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 counter electromotive voltage is generated in the coil 43.

[0152] Thus, in Comparative Example 2, the waveforms of the positive counter electromotive voltage and the negative counter electromotive voltage at least around the rotation angle of 0° are different in the forward rotation and the reverse rotation. Therefore, the magnitude of the peak of the counter electromotive voltage is different in the forward rotation and the reverse rotation. In the configuration of Comparative Example 2, the peak of the counter electromotive voltage is smaller in the forward rotation or the reverse rotation than in Comparative Example 1, and it cannot be said that the counter electromotive voltage is suitable for half-wave rectification. In addition, since the peak of the counter electromotive voltage is different in the forward rotation and the reverse rotation, it is necessary to make the threshold value Vth different in some cases. As a result, as in Comparative Example 1, it becomes necessary for the rate adjustment means 40 to have a means for grasping in advance whether the balance wheel 31 is moving in the forward direction or the reverse direction.

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

[0154] The arrangement of the permanent magnet 41 shown in Fig. 5 is an example, and the permanent magnet 41 may be arranged such that the 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 the magnetization direction of the permanent magnet 41 may be directed toward 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 positioned such that, when the hairspring 32 is in its neutral position of elastic deformation, the boundary B between the N-pole portion 411 and the S-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 mechanical timepiece 1.

[0156] [Circuit diagram] Here, an overview of the rectifier circuit in this embodiment will be described with reference to Fig. 14A. Fig. 14A is a circuit diagram showing an example of the 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 a back electromotive voltage generated in the coil 43 by the motion of the permanent magnet 41. The rectifier circuit 50 is a circuit that eliminates the negative voltage portion of the back electromotive voltage generated in the coil 43 and converts it into direct current.

[0158] The transistors TP1 and TP2 are respectively connected to the first terminal O1 and the second terminal O2 of the coil 43. The back electromotive voltage 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 voltage. 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 O1 corresponding to these transistors can be extracted as detection signals, which are voltage signals.

[0159] The transistors P11 and P12 are connected to the first terminal O1 of the coil 43, and the transistors P21 and P22 are connected to the second terminal O2 of the coil 43. The transistors P11, P12, P21, and P22 are ON / OFF controlled by a speed control pulse from the 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, a current flows through the coil 43 and the capacitor C is charged. When the capacitor C is charged to a certain extent, the power supply circuit 60 is started. Then, as the power supply circuit 60 is started, the control circuit 44 is started, 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, so that the circuit configuration can be simplified and voltage drop can be prevented. The circuit shown in FIG. 14A is an example, and as shown in FIG. 14B, a voltage doubler rectifier circuit that can also rectify the 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 the voltage doubler rectifier circuit, the number of diodes can be reduced compared to a full-wave rectifier circuit. That is, it is possible to prevent voltage drop from occurring.

[0161] [Details about the rate adjustment control] Hereinafter, details of the rate adjustment control in this embodiment will be described 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 about speed adjustment control: Output timing of speed adjustment 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 shifted.

[0165] Therefore, in this embodiment, in the forward and reverse rotational motion of the permanent magnet 41, the 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 the permanent magnet 41 rotates in the forward direction from a rotation angle of -180° to 0°. That is, the speed control pulse is output during the period before the balance wheel 31 is supplied with power from the power spring 11. This makes it possible to output the speed control pulse when the angular velocity of the permanent magnet 41 is relatively slow. In addition, in this embodiment, the balance wheel 31 receives air resistance from the air resistance member 15 between a rotation angle of 225° to 135°, so that the angular velocity of the permanent magnet 41 is particularly slow between a rotation angle of 180° to 0°. The same is true between a rotation angle of -225° to -135°. In this way, in the forward and reverse motion of the forward and reverse rotational motion of the balance wheel 31, it is preferable to perform the 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, it is possible to prevent deviation in the output timing of the speed control pulse. As a result, it is possible to maintain the rate accuracy. In Fig. 12, the timing for rate adjustment is indicated by a band-shaped area. As shown in the upper graph of Fig. 12, the rate adjustment is performed during the period when the angular velocity of the permanent magnet 41 is slow.

[0167] [Details about the 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 a timing when permanent magnet 41 rotating in the forward direction is at a rotation angle of -90° and at a timing when permanent magnet 41 rotating in the reverse direction is at a rotation angle of 90°.

[0168] 15A, when a speed control pulse is output to the first terminal O1 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 a repulsive force from the soft magnetic core 42. That is, the forward rotation of the permanent magnet 41 is braked. On the other hand, when a speed control pulse is output to the first terminal O1 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 a repulsive force from the soft magnetic core 42. That is, the reverse rotation of the permanent magnet 41 is 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. That is, 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. That is, 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 during its forward or 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, when adjusting the rate to delay, it is sufficient to energize the first terminal O1, and when adjusting the rate to advance, it is sufficient to energize the second terminal O2.

[0172] [Details about the rate adjustment control: Operation flow of the rate adjustment control] Fig. 16 is a flow chart showing an example of the rate adjustment control of this embodiment. In the following description, a signal detected by the rotation detection circuit 45 when a back electromotive voltage equal to or greater than a predetermined threshold value Vth is generated is defined as a detection signal DE. The control circuit 44 controls the speed control 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, in the forward and reverse rotational movements of the balance wheel 31, 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, and on the reference signal OS.

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

[0175] When the detection signal DE is detected within the output period of the reference signal OS (Y in ST2), that is, when there is no rate deviation, the rate adjustment control is terminated. Note that Fig. 17 is a timing chart showing an example when 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), i.e., if a rate deviation has occurred, 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] When 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] Fig. 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 from the detection timing of the detection signal DE. As shown in Fig. 18, the period in which the detection signal DE is detected is different before and after the output of the speed control pulse p1. That is, the period in which the detection signal DE is detected after the speed control pulse p1 is output is longer than the period 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] When 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. 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 period in which the detection signal DE is detected is different before and after the output of the speed control pulse p2. That is, the period in which the detection signal DE is detected after the speed control pulse p2 is output is shorter than the period in 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 or output periods. This is because the amount of correction caused by outputting 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 the rate adjustment control: Operation flow of the first modified example of the rate adjustment control] Next, a first modified example of the rate adjustment control will be described with reference to Figures 20 and 21. Figure 20 is a flow chart showing the first modified example of the 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 which 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 power generation caused by the motion of the permanent magnet 41 (Y in ST1), the rate adjustment means 40 performs the rate adjustment control.

[0185] The control circuit 44 determines whether or not the forward / reverse rotation of the balance wheel 31 (permanent magnet 41) is the eighth. Specifically, the control circuit 44 determines whether or not 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 judges 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 adds 1 to the count number of the first counter without performing rate adjustment (ST23).

[0189] When 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 Fig. 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 timing at which the detection signal DE is detected 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 so as to delay the rate.

[0192] The lower part of Fig. 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 delayed by t from 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 timing at which the detection signal DE is detected 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] Also, 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 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, the rate adjustment is not performed every second, so that the number of times that the rate adjustment pulse is output can be reduced, and as a result, power consumption can be reduced.

[0195] [Details of the rate adjustment control: Operation flow of the second modified example of the rate adjustment control] Next, a second modified example of the rate adjustment control will be described with reference to Figures 22 and 23. Figure 22 is a flow chart showing the second modified example of the rate adjustment control.

[0196] In this example, the rate adjustment means 40 may have 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 of 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, the second counter is set to 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 power generation caused by the motion of the permanent magnet 41 (Y in ST1), the rate adjustment means 40 performs the rate adjustment control.

[0198] The control circuit 44 determines whether or not the forward / reverse rotation of the balance wheel 31 (permanent magnet 41) is the eighth. Specifically, the control circuit 44 determines whether or not 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 period difference 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).Then, 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 the count number 0 (ST24).

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

[0205] If the count number of the second counter is not 7 (N in ST36), the control circuit 44 judges whether the count number of the second counter is smaller than 7 (ST37). If the count number of the second counter is smaller 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 larger 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). After that, the control circuit 44 resets the count number of the second counter to 7 (ST38).

[0206] In the second modified example of the rate adjustment control described above, the rate adjustment is not performed every second, so that the number of times that the rate adjustment pulse is output can be reduced, and as a result, power consumption can be reduced.

[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, the second counter is 5 by the time the first counter reaches 8. That is, the timing at which the detection signal DE is detected 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 a pulse group including a plurality of single pulses as shown in FIG. 24. By making the speed control pulse a pulse group, it is possible to absorb manufacturing variations and driving variations of the speed control mechanism 30. In this case, instead of changing the output period of the speed control pulse as shown in FIG. 21, the attractive or repulsive force acting on the permanent magnet 41 may be controlled by changing the duty ratio of the speed control pulse. The duty ratio indicates the proportion of the pulse output within a predetermined period. FIG. 24 shows an example of a speed control pulse with a duty ratio of 3 / 5.

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

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

[0211] [Details of the rate adjustment control: Rate adjustment control considering the effect of disturbances] Fig. 26 is a timing chart showing an example of rate adjustment control considering the influence of disturbance. Fig. 27 is a flow chart showing an example of rate adjustment control considering the influence of disturbance. Fig. 28 is a flow chart showing rate adjustment control considering the influence of disturbance in the 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 if an impact is applied to the mechanical timepiece 1, the back electromotive force may be disturbed due to an instantaneous disturbance, and the detection signal DE may not be detected. In this case, the control circuit 44 may erroneously determine that the rate has significantly decreased.

[0213] Therefore, as shown in FIG. 26, if the detection signal DE is not detected in a predetermined period including before and after the output period of the reference signal OS, the rate adjustment may not be performed. The upper part of FIG. 26 shows a state in which the detection signal DE is not detected near the measurement time of 2.0 [s] due to the action of disturbance. Specifically, the detection signal is not detected in 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 FIG. 26 shows an example in which the periods dt1 and dt2 are the same length, but they may be different lengths. In addition, it is preferable that the speed control pulse is output while avoiding the periods dt1 and dt2. This is because outputting the speed control pulse may disturb the coil waveform (waveform of the back electromotive force), which may reduce 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) during a predetermined detection period (dt1 to ts to dt2) (Y in step ST11) after the power supply circuit 60 is started by power generation caused by the motion of the permanent magnet 41 (Y in ST1). On the other hand, an example in which rate adjustment is not performed when a detection signal DE is not output (detected) during the predetermined detection period (dt1 to ts to dt2) (N in step ST11) is shown. Note that each step shown in Fig. 27 is the same as that shown in Fig. 16 except for ST11, and detailed explanations thereof will be omitted.

[0215] 28 shows an example in which the rate adjustment is performed when the detection signal DE is output (detected) during a predetermined detection period (dt1 to ts to dt2) (Y in step ST11) after the power supply circuit 60 is started by generating electricity through the motion of the permanent magnet 41 (Y in ST1). On the other hand, when the detection signal DE is not output (detected) during the predetermined detection period (dt1 to ts to dt2) (N in step ST11), the 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 to start counting the number of times the detection signal DE is detected again.

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

[0217] 26 to 28, highly accurate rate adjustment is possible even when disturbances are applied. In addition, unnecessary output of speed control pulses can be suppressed, reducing power consumption.

[0218] [Details of the rate adjustment control: Rate adjustment control when the detection of the detection signal is continuously failed] Fig. 29 and Fig. 30 are timing charts showing an example of rate adjustment control when failure to detect a detection signal continues. Fig. 31 is a flowchart showing an example of rate adjustment control assuming that failure to detect a detection signal continues.

[0219] When the power spring 11 is unwound, the torque of the rotor 41 weakens, and the back electromotive force may not exceed the threshold value 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 perform rate adjustment.

[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 to detect the detection signal DE and a fourth counter that counts the number of consecutive successes to detect the detection signal DE are used to switch between a "speed control pulse output setting" that outputs a speed control pulse and a "speed control pulse stop setting" that stops the output of the speed control pulse.

[0221] Specifically, a configuration is adopted in which, when the third counter reaches 10, i.e., when the detection signal DE fails to be detected 10 times in succession, 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 succession, the setting is switched to the speed control pulse output setting. Note that the count number that triggers the setting switch is merely 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 ten times in succession, causing the setting to be switched to stop the speed control pulse.

[0223] In Fig. 30, an example is shown in which the speed control pulse stop setting is switched to when the detection signal DE fails to be detected 10 times in succession, and then the speed control pulse output setting is switched to when the detection signal DE is successfully detected 20 times in succession, thereby outputting the speed control pulse p1. 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. 26-28.

[0224] In the flowchart shown in Fig. 31, after the power supply circuit 60 is started by generating electricity through the motion of the permanent magnet 41 (Y in ST1), 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 the detection of the detection signal DE has failed 10 times in succession. 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 judges 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] Also, if the speed control pulse stop setting is in progress in ST41 (Y in ST41), the control circuit 44 judges whether the count number of the fourth counter is 20 or not (ST51). That is, the control circuit 44 judges whether the detection signal DE has been successfully detected 20 times in succession. If the fourth counter is not 20 (N in ST51), the control circuit 44 judges whether the detection signal DE has been output (detected) during a predetermined detection period (dt1 to ts to dt2) (ST52). If the detection signal DE has not been output (detected) during 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) during the predetermined detection period (dt1 to ts to dt2) (Y in ST52), the control circuit 44 adds 1 to the count number of the fourth counter (ST54).

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

[0229] Also, if the count number of the third counter is 10 in ST42 (Y in ST42), the third counter is reset (ST61) and the speed control pulse output setting is switched to (ST62). When the power supply circuit 60 stops and then starts operating, the amount of charge stored in the capacitor C is small, so the power supply circuit 60 is likely to stop again. Therefore, when the power supply circuit 60 stops and then starts operating, it is preferable to increase the number of consecutive successful detection signals DE required before starting rate adjustment. For example, in ST51 of FIG. 31, when the count number of the fourth counter is 60, that is, when the detection signal DE is successfully detected 60 times in a row, the speed control pulse output setting is switched to.

[0230] In the examples of Figs. 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 voltage Vth is not detected for a predetermined number of consecutive seconds, the mechanical timepiece 1 may have a function of informing the user that the mechanical timepiece 1 is in a state where it is likely to stop. As a means of informing, for example, the position indicated by the hands may be used. This makes it possible to prompt the user to perform an operation to wind up the power spring 11.

[0232] Also, in the examples of Figs. 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, when the threshold Vth is 0.5V, if the detection of the detection signal DE fails 10 times in succession, the threshold voltage may be set to 0.25V. This makes it easier for the power supply circuit 60 to stop, but allows the accuracy of the rate to be maintained. 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. Also, 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 about the rate adjustment control: Rate adjustment control taking into account the rotation direction of the balance wheel] 32 is a timing chart showing an example of the output timing of the reference signal. The rotation angle of the balance wheel 31 may differ between the forward and reverse directions due to manufacturing variations during assembly of the mechanical timepiece 1, or due to position adjustment of the balance wheel 31 by the support member 33 during shipping inspection. If the rotation angle differs, the timing at which the detection signal DE is detected will differ between the forward and reverse directions. This may result in unnecessary output of a speed control pulse even though there is no rate deviation overall.

[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 (two-second) basis. The upper part of FIG. 32 shows an example of a back electromotive voltage 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 in which the reference signal OS is set on a two-step (two-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 may be realized by the control circuit 44 performing two-system control in two-step units (two-second units). Then, when a rate abnormality is detected in any of the control systems, a rate adjustment may be performed. In order to simplify the circuit configuration, only one control system may be used in which the output interval is either tr1 or tr2.

[0235] In the example shown in FIG. 32, the reference signal OS is set to a two-step standard (tr1 and tr2) and the rate is adjusted accordingly, 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 in the case where the reference signal OS is set on a one-step (one second) basis, i.e., in the example shown in Fig. 17 and the like. In the example shown in the middle part of Fig. 32, the peak positions of the back electromotive force differ between the forward and reverse directions, so that the output timing of the even-numbered detection signals DE from the left is always shifted, even though there is no rate shift overall. In such a case, a speed control pulse is output unnecessarily.

[0237] [summary] In this embodiment, a configuration is adopted in which the angular velocity of the balance wheel 31 is slowed down, so that it is possible to suppress wear of each mechanism that transmits power (for example, the escape wheel 21 and the anchor 22). As a result, the durability of the mechanical timepiece 1 is improved. In addition, a configuration is adopted in which the angular velocity of the balance wheel 31 is slowed down during the period in which the balance wheel 31 moves in the forward and reverse directions by using the air resistance member 15. This makes it possible to ensure a sufficient amount of power generation by generating power during the period in which the balance wheel 31 is not subjected to air resistance by the air resistance member 15 while slowing down the rotation period of the balance wheel 31. In addition, by performing rate adjustment during the period in which the balance wheel 31 is subjected to air resistance by the air resistance member 15 or the period after it has been subjected to air resistance, it is possible to maintain the accuracy of the rate adjustment. In addition, a configuration is adopted in which the permanent magnet 41 is arranged so as to obtain a back electromotive voltage suitable for half-wave rectification, so that it is possible to efficiently extract power 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 the detection accuracy may be reduced if there are 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 materials for 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 for fixing 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 given here are merely examples and are not limited to these.

[0240] Also, as described above, by making the hairspring 32 from resin in order to reduce the Young's modulus, the magnetic effect on the permanent magnet 41 can be reduced compared to when the hairspring 32 is made from metal. Also, if the hairspring 32 is made from a magnetic metal, it may be magnetically affected by the permanent magnet 41, and the shape and attitude of the hairspring 32 may be displaced. In this embodiment, by making the hairspring 32 from resin, the shape and attitude of the hairspring 32 itself can be stabilized. Also, 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 disturbed even when an external magnet approaches the mechanical timepiece 1, and allows for stable rate adjustment.

[0241] In the present embodiment, as shown in FIG. 5, 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 the present invention is not limited to this. For example, the first end 421a and the second end 422a may not have the first welded portion 423 and the second welded portion 424, and the first end 421a and the second end 422a may be magnetically separated via a gap. In addition, the present invention is not limited to a case where the magnetic coupling is completely separated. 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] 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 viewed from the outside.

[0243] In addition, in the present embodiment, an example in which the air resistance member 15 is provided has been described, but the present invention is not limited to this, and the air resistance member 15 may not be provided. Furthermore, if there is no air resistance member 15, 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 to slow down the movement of the balance wheel 31, and the duration is longer than that of a conventional mechanical watch with 6 to 8 vibrations. In other words, the reduction in duration due to air resistance can be compensated for by slowing down the movement of the balance wheel 31. Therefore, a sufficient duration can be achieved as a mechanical watch. [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 second 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 portion, 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 hairspring, 321 outer end portion, 322 inner end portion, 322a fixed portion, 322b Pitch expansion portion, 33 support member, 33a pipe, 33b screw, 34 hair support, 35 frame member, 35a convex portion, 40 speed adjustment means, 41 permanent magnet, 42 soft magnetic core, 421 first magnetic portion, 421a first end portion, 422 second magnetic portion, 422a second end portion, 43 coil, 44 control circuit, 45 rotation detection circuit, 46 speed control pulse output circuit, 47 frequency divider circuit, 48 oscillation circuit, 50 rectifier circuit, 60 power supply circuit, 70 quartz crystal oscillator, n11, n12, n21, n22 notches.

Claims

[Claim 1] A power source; 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 which rotates in a forward and reverse direction in accordance with the forward and reverse rotation of the balance wheel; A coil and a soft magnetic core including a first end portion provided along an outer periphery of the permanent magnet, and a second end portion provided along an outer periphery of the permanent magnet and disposed opposite the first end portion via the permanent magnet, the soft magnetic core forming a magnetic circuit together with the coil; a control circuit for adjusting the rate based on a detection voltage generated in the coil by the motion of the permanent magnet accompanying the forward and reverse motions of the balance wheel and a reference frequency of a reference signal source; a rectifier circuit that rectifies a current generated in the coil by a motion of the permanent magnet accompanying the forward and reverse motions of the balance wheel; a power supply circuit that drives the control circuit based on the current rectified by the rectifier circuit; having The permanent magnet is arranged such that a magnetizing direction faces the first end or the second end when the hairspring is in a neutral position of its elastic deformation. Mechanical watch.

Images