Mechanical watch

Abstract

To provide a mechanical watch 1 capable of improving the accuracy of rate adjustment.SOLUTION: A mechanical watch 1 includes: a permanent magnet 40; a coil 43; a rotation detection circuit 45; and rate adjustment means 40 for acting brake force corresponding to a brake rank currently set among a plurality of brake forces corresponding to a plurality of brake ranks, respectively. The rate adjustment means 40 includes a control circuit 44 for controlling the brake rank. The control circuit 44 can switch the brake rank according to the detection timing of a detection signal DE to a predetermined reference timing, and controls the brake rank so that the fluctuation range of the brake rank is larger when the advance or delay of the detection timing to the reference timing is different as compared with when either the advance or delay of the detection timing to the reference timing is continuous, in detecting the last detection signal DE by the rotation detection circuit 45 and in detecting this detection signal DE.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to a mechanical watch.

Background Art

[0002] Patent Documents 1 and 2 disclose technologies for adjusting the pace of a watch by electromagnetic braking force. Such technologies can suppress the pace deviation that accumulates over time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when there is a change in the posture of the watch or an external impact, the pace may deviate significantly in a short time. Even in such cases, there is a demand for quickly and accurately adjusting the pace deviation.

[0005] The present invention has been made in view of the above problems, and its object is to provide a mechanical watch that improves the accuracy of pace adjustment.

Means for Solving the Problems

[0006] (1) A speed control mechanism including a power source, a balance wheel driven by power from the power source, and a hairspring that elastically deforms to cause the balance wheel to rotate in forward and reverse directions; a bipolarized permanent magnet that rotates in forward and reverse directions in conjunction with the forward and reverse rotation of the balance wheel, a coil, a rotation detection circuit that detects a detection signal based on a detection voltage generated in the coil by the movement of the permanent magnet accompanying the forward and reverse movement of the balance wheel; and a rate adjustment means that brakes the permanent magnet and applies a braking force corresponding to the currently set braking rank from among a plurality of braking forces corresponding to each of a plurality of braking ranks, wherein the rate adjustment means is A mechanical clock including a control circuit for controlling a braking rank, wherein the control circuit is configured to switch the braking rank according to the detection timing of the detection signal relative to a predetermined reference timing corresponding to the output timing of a reference signal of a reference signal source, and controls the braking rank such that the range of variation of the braking rank is larger when the detection timing is ahead or behind the reference timing between the previous detection of the detection signal by the rotation detection circuit and the current detection of the detection signal is ahead or behind the reference timing than when either one of the detection timings is ahead or behind the reference timing is consecutive.

[0007] (2)(1) A mechanical clock in which the control circuit is configured to switch between a high braking mode and a low braking mode according to the detection timing relative to the reference timing, and the current braking rank in the high braking mode is set to a higher braking rank than the current braking rank in the low braking mode.

[0008] (3)(2) A mechanical clock in which the rate adjustment means includes a braking circuit that applies a braking force to brake the permanent magnet by short-circuiting the terminals of the coil.

[0009] (4)(3) A mechanical clock wherein the braking circuit applies a braking force corresponding to the current braking rank in the high braking mode when the detection timing is ahead of the reference timing when the rotation detection circuit detects the current detection signal, and applies a braking force corresponding to the current braking rank in the low braking mode when the detection timing is behind the reference timing when the rotation detection circuit detects the current detection signal.

[0010] (5)(3) or (4), the control circuit sets the current braking rank in the high braking mode and the low braking mode based on the detection timing of the previous detection signal relative to the reference timing.

[0011] A mechanical clock in which, in any of (6)(2) to (5), the control circuit switches from the low braking mode to the high braking mode when the current detection timing is ahead of the reference timing when the rotation detection circuit detects the current detection signal, and when the previous detection timing was behind the reference timing when the rotation detection circuit detected the previous detection signal.

[0012] (7)(6) The control circuit switches from the low braking mode to the high braking mode and increases the current braking rank in the low braking mode, a mechanical clock.

[0013] A mechanical clock in which, in (8)(6) or (7), the control circuit increases the current braking rank in the low braking mode, and if the current braking rank in the low braking mode after the braking rank has been increased is different from the current braking rank in the high braking mode, it switches from the low braking mode to the high braking mode and increases the current braking rank in the low braking mode, and if the current braking rank in the low braking mode increases the current braking rank in the low braking mode after the braking rank has been increased is the same as the current braking rank in the high braking mode, it switches from the low braking mode to the high braking mode and maintains the braking rank in the low braking mode.

[0014] A mechanical clock in which, in any of (9)(2) to (8), the control circuit increases the current braking rank in the high braking mode if, at the time of the current detection of the detection signal by the rotation detection circuit, the detection timing is ahead of the reference timing, and at the time of the previous detection of the detection signal by the rotation detection circuit, the detection timing was ahead of the reference timing.

[0015] A mechanical clock in which, in any of (10)(2) to (9), the control circuit switches from the high braking mode to the low braking mode when the current detection of the detection signal by the rotation detection circuit is delayed relative to the reference timing, and when the previous detection of the detection signal by the rotation detection circuit was advanced relative to the reference timing.

[0016] (11)(10) The control circuit switches from the high braking mode to the low braking mode and lowers the current braking rank in the high braking mode, a mechanical clock.

[0017] A mechanical clock in which, in (12)(10) or (11), the control circuit lowers the current braking rank in the high braking mode, and if the current braking rank in the high braking mode after the braking rank has been lowered is different from the current braking rank in the low braking mode, it switches from the high braking mode to the low braking mode and lowers the braking rank in the high braking mode. A mechanical clock in which, in which case, the control circuit lowers the current braking rank in the high braking mode, and if the current braking rank in the high braking mode after the braking rank has been lowered is the same as the current braking rank in the low braking mode, it switches from the high braking mode to the low braking mode and maintains the braking rank in the high braking mode.

[0018] A mechanical clock in which, in any of (13)(2) to (12), the control circuit lowers the current braking rank in the low braking mode if, at the time of the current detection of the detection signal by the rotation detection circuit, the detection timing is delayed with respect to the reference timing, and at the time of the previous detection of the detection signal by the rotation detection circuit, the detection timing was delayed with respect to the reference timing.

[0019] (14)(2) to (13), the control circuit maintains the braking rank for a predetermined number of consecutive times if the detection timing is ahead of the reference timing, or if the detection timing is behind the output timing for a predetermined number of consecutive times, and then sets the braking rank based on the detection timing of the current detection signal relative to the output timing. [Effects of the Invention]

[0020] According to the above aspects (1) to (14) of the present invention, it is possible to provide a mechanical watch that improves the accuracy of rate adjustment. [Brief explanation of the drawing]

[0021] [Figure 1]It is a perspective view showing the floor of this embodiment and each member incorporated therein. [Figure 2] It is a perspective view showing the mechanism for transmitting power in this embodiment and its surroundings. [Figure 3] It is an exploded perspective view showing the state where the speed control mechanism and the members around it in this embodiment are disassembled from the floor. [Figure 4] It is a plan view showing the soft magnetic core of this embodiment and its surroundings, and an enlarged plan view showing a part thereof enlarged. [Figure 5] It is a block diagram showing the overall configuration of the mechanical watch according to this embodiment. [Figure 6] It is a diagram for explaining the relationship between the operation of the tens wheel in this embodiment and the back electromotive voltage generated in the coil. [Figure 7] It is a circuit diagram showing an example of the circuit of the mechanical watch. [Figure 8] It is a timing chart showing an example of braking control. [Figure 9] It is a diagram showing an example of the action period of the electromagnetic brake in each braking link in this embodiment. [Figure 10] It is a diagram showing an example of the transition of the braking link in this embodiment. [Figure 11] It is a diagram showing an example of the transition of the braking link in this embodiment. [Figure 12] It is a flowchart showing an example of the braking control in this embodiment. [Figure 13] It is a diagram showing an example of the transition of the braking link in a modified example of this embodiment.

Mode for Carrying Out the Invention

[0022] Hereinafter, an embodiment of the present invention (hereinafter referred to as this embodiment) will be described in detail based on the drawings.

[0023] [Outline of the Overall Configuration] First, an overview of the overall configuration of the mechanical clock 1 according to this embodiment will be described with reference to Figures 1 to 5. Figure 1 is a perspective view showing the main plate and the various components incorporated therein in this embodiment. Figure 2 is a perspective view showing the power transmission mechanism and its surroundings in this embodiment. Figure 3 is an exploded perspective view showing the speed control mechanism and its surrounding components separated from the main plate in this embodiment. Figure 4 is a plan view showing the soft magnetic core and its surroundings in this embodiment, and an enlarged plan view showing a part of it enlarged. Figure 5 is a block diagram showing the overall configuration of the mechanical clock according to this embodiment. Figures 1 to 3 show the view from the back of the mechanical clock 1. The back side is the side in the thickness direction of the mechanical clock 1 where the back cover of the outer case is located.

[0024] Mechanical watch 1 is a watch that uses a mainspring 11 as a power source and controls the movement of the mainspring 11 by an escapement mechanism 20 and a regulating mechanism 30, and also drives the hands. Mechanical watch 1 consists of a base plate 10 into which the mechanisms for driving the hands are incorporated, housed in an outer case. In this embodiment, the outer case is not shown. The crown, which is located on the side of the outer case, is also not shown. The crown is attached to the end of the winding stem 2 shown in Figure 1.

[0025] [Overall Configuration Overview: Drive Mechanism Configuration] The outline of the drive mechanism of the mechanical clock 1 will be described. In this embodiment, the mechanism including the power source, the mainspring 11, the gear train 12, and the pointer shaft 13 is referred to as the "drive mechanism." Note that in Figure 2, only the second hand 131 of the pointers is shown. The drive mechanism shown in Figure 2 is an example and is not limited to this, and may include gears other than those shown.

[0026] The mainspring 11 is housed in a barrel 110, which is made of a metal strip and has multiple teeth formed on its outer circumference. The barrel 110 is disc-shaped and has a cavity formed inside that houses the mainspring 11. The inner end of the mainspring 11 is fixed to the barrel arbor (not shown), which is a rotating shaft located 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 the user, the winding stem 2 rotates. As the winding stem 2 rotates, the mainspring 11 is wound up. The wound mainspring 11 is then unwound by its elastic force. The barrel 110 rotates in conjunction with the movement of the mainspring 11 during this process.

[0027] The gear train 12 includes at least a second wheel 122, a third wheel 123, and a fourth wheel 124. The second wheel 122 includes a pinion that engages with several teeth formed on the barrel 110, which functions as the first wheel, a pivot shaft, and several teeth, and transmits the rotation of the barrel 110 to the third wheel 123. The pivot shaft of the second wheel 122 is the pointer shaft of the minute hand (not shown). The third wheel 123 includes a pinion that engages with several teeth of the second wheel 122, a pivot shaft, and several teeth, and transmits the rotation of the second wheel 122 to the fourth wheel 124. The fourth wheel 124 includes a pinion that engages with several teeth of the third wheel 123, a pivot shaft, and several teeth, and transmits the rotation of the third wheel 123 to the escapement mechanism 20. As shown in Figure 2, the pivot shaft of the fourth wheel 124 is the pointer shaft 13 of the second hand 131.

[0028] [Overall Configuration Overview: Configuration of escapement mechanism 20 and speed control mechanism 30, and overview of their operation] Next, the escapement mechanism 20 and the regulating mechanism 30 will be described. Power from the mainspring 11 is transmitted to the escapement mechanism 20 and the regulating mechanism 30 through the gear train 12. The escapement mechanism 20 consists of an escape wheel 21 and an anchor 22. The regulating mechanism 30 consists of a balance wheel 31 and a hairspring 32. The regulating mechanism 30 is sometimes called the balance wheel.

[0029] The escape wheel 21 is a component that, by meshing with the anchor 22, receives the rhythm ticked by the speed control mechanism 30 from the anchor 22 and converts it into regular reciprocating motion. The escape wheel 21 includes a pinion that meshes with multiple teeth of the fourth wheel 124, a rotating shaft, and multiple teeth. As shown in Figure 2, the multiple teeth of the escape wheel 21 are formed with wider spacing in the circumferential direction than the teeth of each gear of the gear train 12.

[0030] The anchor 22 rotates in both forward and reverse directions around the anchor pivot 221 shown in Figure 4 as its axis of rotation. The anchor 22 extends from the anchor pivot 221 toward the center of the balance wheel 31 (balance pivot 311) and has a rod portion 222 that strikes a bobblehead (not shown) that rotates together with the balance pivot 311. The bobblehead is fixed to the balance pivot 311.

[0031] Furthermore, the anchor 22 has a first arm 223 to which a pawl 223a that strikes against multiple teeth of the escape wheel 21 is attached, and a second arm 224 that extends in the opposite direction to the first arm 223 and to which a pawl 224a that strikes against multiple teeth of the escape wheel 21 is attached. The pawls 223a and 224a may be made of a stone such as sapphire.

[0032] The balance wheel 31 rotates in both forward and reverse directions around the balance shaft 311 as its center of rotation, power transmitted by the gear train 12. In the following explanation, the forward rotation may be referred to as "forward rotation," and the reverse rotation as "reverse rotation."

[0033] As shown in Figure 3, the balance wheel 31 is preferably circular in shape. However, the shape of the balance wheel 31 shown in Figure 3 is just an example, and the shape of the balance wheel 31 is arbitrary. The balance shaft 311 is supported by the support member 33 shown in Figure 3.

[0034] The hairspring 32 undergoes expansion and contraction (elastic deformation) to cause the balance wheel 31 to rotate in forward and reverse directions. The hairspring 32 is spiral-shaped, with its inner end fixed to the balance staff 311 and its outer end fixed to the hairspring support 34. The hairspring support 34 is fixed to the base plate 10 together with the support member 33. Furthermore, as shown in Figure 3, the hairspring support 34 is provided sandwiched between the support member 33 and the frame member 35.

[0035] The escape wheel 21 rotates in conjunction with the rotation of the fourth wheel 124. As the escape wheel 21 rotates, it collides with the pawl 223a of the anchor 22, causing the anchor 22 to rotate around the anchor stem 221. The rotating shaft 222 of the anchor 22 collides with the balance stone fixed to the balance stem 311, causing the balance wheel 31 to rotate. As the balance wheel 31 rotates, the pawl 224a of the anchor 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 pawl 223a of the anchor 22 is released, and the escape wheel 21 rotates again. As will be described later, since the balance wheel 31 is designed to make one back-and-forth motion in 2 seconds, the escape wheel 21 makes one step of motion per second.

[0036] In this embodiment, a resin material with a low Young's modulus is used as the material for the hairspring 32. This makes it possible to achieve slower vibration of the balance wheel 31 compared to when it is made of metal. If slower vibration were to be achieved with a metal hairspring, the cross-sectional area of ​​the hairspring 32 would have to be reduced to a level that is difficult to process, or the length of the hairspring would have to be increased to a level that is difficult to handle.

[0037] In this embodiment, a resin with a Young's modulus of approximately 5 [GPa] was used as the material for the hairspring 32. Specifically, polyester was used as the material for the hairspring 32. The hairspring 32 made of resin material may be manufactured, for example, by laser processing. The Young's modulus of a typical metal hairspring is about 200 [GPa]. The Young's modulus shown here is just an example, and the Young's modulus of the hairspring 32 should preferably be 20 [GPa] or less. That is, the Young's modulus of the hairspring 32 should preferably be one-tenth or less of the Young's modulus of a metal hairspring. More preferably, the Young's modulus of the hairspring 32 should be 10 [GPa] or less. That is, the Young's modulus of the hairspring 32 should preferably be one-twentieth or less of the Young's modulus of a metal hairspring. Furthermore, as long as the Young's modulus is 20 [GPa] or less, the hairspring 3 may be made of materials such as paper or wood.

[0038] In this embodiment, the rotation angle [deg] of the balance wheel 31 and the permanent magnet 41 is set to 0° when the hairspring 32 is in the neutral position of elastic deformation. In other words, the neutral position of elastic deformation of the hairspring 32 is the position where the hairspring 32 is at its natural length. Power from the power spring 11 is supplied to the balance wheel 31 when the hairspring 32 is in the neutral position of elastic deformation. That is, the balance wheel 31 and the permanent magnet 41 are in a power supply position where power from the power spring 11 is supplied when the rotation angle is 0°. Furthermore, as will be described later, in this embodiment, the permanent magnet 41 is in a magnetically balanced position when the rotation angle is 0°.

[0039] Furthermore, in this embodiment, the balance wheel 31 is designed to be driven within a rotation angle range of 340° to -340°. Therefore, the permanent magnet 41 is also driven within a rotation angle range of 340° to -340°. However, this is just one example, and the range of movement of the balance wheel 31 should preferably be greater than or equal to a rotation angle range of 270° to -270°. By increasing the range of movement of the balance wheel 31 to a certain extent, it is possible to achieve low-speed vibration of the balance wheel 31.

[0040] As explained above, the regulating mechanism 30 causes the balance wheel 31 to repeatedly rotate in forward and reverse directions (reciprocating motion) at a constant period by the expansion and contraction of the hairspring 32. The escapement mechanism 20 continuously applies force to the balance wheel 31 to cause it to reciprocate. Through this configuration and operation, the hands such as the second hand 131 are driven.

[0041] [Overall Configuration Overview: Configuration of the Rate Adjustment Mechanism 40] Next, the configuration of the rate adjustment means 40 will be described. The mechanical clock 1 according to this embodiment includes a drive mechanism, an escapement mechanism 20, a regulating mechanism 30, and a rate adjustment means 40.

[0042] The rate adjustment means 40 comprises a permanent magnet 41, a soft magnetic core 42 (sometimes called a stator), a coil 43, and various circuits (see Figure 5). The rate adjustment means 40 adjusts the rate based on a detection signal detected based on the forward and reverse rotational motion of the permanent magnet 41 and the reference frequency of a crystal oscillator 70, which is a reference signal source. In this embodiment, as shown in Figure 8 and other figures described later, the output period of the reference signal OS is set to an output period ts having a predetermined width. In this embodiment, a crystal oscillator 70 is used as the reference signal source to achieve high frequency accuracy, but it is not limited to this, and for example, a CR oscillator composed of a capacitor and a resistor may be used.

[0043] Although not shown in the diagram, the coil 43 is preferably positioned so as to overlap with the inner frame, which is located inside the outer casing, 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 positioned within that notch.

[0044] The permanent magnet 41 is a bipolar, disc-shaped rotating body, magnetized radially with a north pole and a south pole. That is, the permanent magnet 41 is a magnet that includes a north pole portion 411 and a south pole portion 412.

[0045] The permanent magnet 41 is attached to the balance staff 311, which is the rotation axis of the balance wheel 31, and is configured to rotate in the forward and reverse directions in accordance with the forward and reverse rotational motion of the balance wheel 31 (balance staff 311). That is, the permanent magnet 41 rotates in the forward and reverse directions together with the balance wheel 31 so that its rotation angle is the same as the rotation angle of the balance wheel 31. The permanent magnet 41 is preferably fixed to the balance staff 311 by press-fitting or adhesive.

[0046] The permanent magnet 41 is preferably an isotropic magnet whose easy magnetization axis is oriented in a random direction. Furthermore, the permanent magnet 41 is preferably magnetized by applying a magnetic field using a Helmholtz coil or the like while attached to the tension rod 311. By employing this magnetization method, the magnetization direction of the permanent magnet 41 can be precisely aligned.

[0047] The soft magnetic core 42 is made of a soft magnetic material and, as shown in Figure 4, has a first magnetic portion 421 including a first end portion 421a provided along the outer circumference of the permanent magnet 41, and a second magnetic portion 422 including a second end portion 422a provided along the outer circumference of the permanent magnet 41, and together with the coil 43, constitutes a magnetic circuit. Both the first end portion 421a and the second end portion 422a have a semicircular inner surface shape and are arranged facing each other via the permanent magnet 41.

[0048] In this embodiment, when the hairspring 32 is in the neutral position of elastic deformation, the permanent magnet 41 has its north pole portion 411 positioned on the second magnetic portion 422 side and its south pole portion 412 positioned on the first magnetic portion 421 side (see enlarged view of Figure 4). The arrangement of the north pole portion 411 and the south pole portion 412 may be reversed, but in that case, the winding direction of the coil 43 must be reversed compared to this embodiment.

[0049] Furthermore, as shown in Figure 3, the soft magnetic core 42 is fixed to the support member 33 by a fixing device consisting of a pipe 33a and a screw 33b. With this configuration, the soft magnetic core 42 is assembled to the base plate 10 together with the support member 33.

[0050] Furthermore, among the components assembled to the base plate 10, it is desirable that components located close to the permanent magnet 41, excluding the soft magnetic core 42, such as the support member 33, hairspring holder 34, frame member 35, hairspring 32, and balance wheel 31, be made of non-magnetic material so as not to affect the forward and reverse rotational motion of the speed control mechanism 30 or the back electromotive force generated by the coil 43 described later.

[0051] Furthermore, as shown in Figure 4, 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 positioned opposite the first welded portion 423 via a permanent magnet 41. It is preferable that the first welded portion 423 and the second welded portion 424 be formed within a gap that physically separates the first end 421a and the second end 422a.

[0052] The permanent magnet 41 is in a magnetically balanced position when its magnetization direction is perpendicular to the opposing direction of the first weld 423 and the second weld 424. In this embodiment, the magnetically balanced position of the permanent magnet 41 is set to a rotation angle of 0°. At this position, the holding torque of the permanent magnet 41 is approximately 0. The opposing direction of the first weld 423 and the second weld 424 is the direction in which the straight line connecting the first weld 423 and the second weld 424 extends, as shown in Figure 4. As shown in Figure 4, 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, notches n11 and n12 are formed on the first end 421a. In addition, a notch n21 is formed on the second end 422a opposite to notch n11 via the permanent magnet 41, and a notch n22 is formed opposite to notch n12 via the permanent magnet 41. The formation of this notch reduces the magnetic influence that the permanent magnet 41 has on the soft magnetic core 42.

[0053] In this embodiment, as shown in Figure 4, an example is shown in which the first end 421a and the second end 422a of the soft magnetic core 42 are integrated via a first weld 423 and a second weld 424, but the embodiment is not limited to this. For example, there may be no first weld 423 and a second weld 424, and the magnetic coupling between the first end 421a and the second end 422a may be separated by a gap. Furthermore, the embodiment is not limited to one in which the magnetic coupling is completely separated. For example, the first end 421a and the second end 422a may be physically connected via a constricted portion which is a separation portion.

[0054] Furthermore, as shown in Figure 5, the rate adjustment means 40 includes a control circuit 44, a rotation detection circuit 45, a speed control pulse output circuit 46, a frequency divider circuit 47, an oscillation circuit 48, and a damping circuit 80. In Figure 5, the permanent magnet 41, soft magnetic core 42, and coil 43 described above are omitted from the illustration. Note that the configuration of the rate adjustment means 40 shown in Figure 5 is just one example. The rate adjustment means 40 does not need to independently provide each circuit shown in Figure 5, but only needs to be capable of realizing each of the functions described below.

[0055] The control circuit 44 is a circuit that controls the operation of each circuit included in the rate adjustment means 40. In particular, as described later, the control circuit 44 controls the braking force that brakes the permanent magnet 41 by controlling the speed control pulse output circuit 46 and the braking circuit 80. Furthermore, the control circuit 44 is configured to switch between a high braking mode and a low braking mode depending on the detection timing of the detection signal relative to the output timing of the reference signal of the reference signal source.

[0056] 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 oscillation signal output from the oscillation circuit 48. By dividing the oscillation signal based on the crystal oscillator 70, the frequency divider circuit 47 generates a reference signal OS that is output approximately every 1000 ms. However, it is not limited to this, and the reference signal OS may be output every 2000 ms or every 3000 ms. In other words, the reference signal OS only needs to be output every second. Furthermore, it is not limited to this, and the reference signal OS only needs to correspond to the period of the speed control mechanism 30.

[0057] The rotation detection circuit 45 detects a detection signal based on the voltage waveform generated in the coil 43 due to the motion of the permanent magnet 41. In this embodiment, the signal detected by the rotation detection circuit 45 when a back electromotive force (EMF) of a predetermined threshold Vth or higher is generated is defined as the detection signal DE. In this embodiment, as shown in Figure 8 below, the predetermined threshold Vth is set to 0.5[V]. However, the back EMF may momentarily exceed the threshold Vth due to external factors such as shock or other noise. To avoid false detections caused by such noise, for example, rotation detection may be performed at intervals of 32[μs], and the starting point for speed control may be the timing when the detection signal DE has been detected two or more predetermined times. However, this is not limited to this, and it may be appropriately determined based on the rotation detection interval, the number of times the detection signal DE has been detected continuously, the number of times the detection signal has been accumulated, etc. The value of the threshold Vth is not limited to 0.5[V]. Furthermore, the threshold Vth may be varied according to the state of the mechanical clock 1. For example, the threshold Vth may be varied according to the winding state of the power mainspring 11. Specifically, when the torque of the power spring 11 is weakened, it is preferable that a lower threshold value is selected from among several pre-set threshold values ​​Vth.

[0058] The speed control pulse output circuit 46 outputs a speed control pulse based on the reference signal generated by the frequency divider circuit 47 and the detection signal DE detected by the rotation detection circuit 45. Specifically, it compares the detection timing of the detection signal DE detected by the rotation detection circuit 45 with the output timing of the reference signal of approximately 1000 Hz. If there is a discrepancy in their timings, the speed control pulse output circuit 46 outputs a speed control pulse to bring the period during which the detection signal DE is detected closer to 1000 ms (= 1 second).

[0059] The speed control pulse is output by energizing coil 43. Therefore, the speed control pulse output circuit 46 should energize coil 43 so that a torque acts to slow down the movement of the permanent magnet 41 when the detection period of the detection signal DE is faster than the reference signal, and energize coil 43 so that a torque acts to speed up the movement of the permanent magnet 41 when the detection period of the detection signal DE is slower than the reference signal. The speed control pulse output when coil 43 is energized so that a torque acts to slow down the movement of the permanent magnet 41 becomes a braking force that brakes the movement of the permanent magnet 41.

[0060] The speed control pulse output circuit 46 is preferably configured to output multiple speed control pulses with different output periods (pulse widths). Furthermore, the speed control pulse output circuit 46 is preferably configured to output multiple speed control pulses with different output voltages.

[0061] [Overall Configuration Overview: Speed ​​Control Mechanism 30 as a Generator] Mechanical clock 1 has a power generation function using 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 in the forward and reverse directions in conjunction with the forward and reverse rotational motion of the balance wheel 31, and power is generated by the current produced in the coil 43 based on the change in the magnetic field caused by the motion of the permanent magnet 41. The power extracted by this operating principle is used to start the power supply circuit 60. Once the power supply circuit 60 is started, the control circuit 44 can be driven. Because of this configuration, in this embodiment, the control circuit 44 can be driven without providing a separate power source such as a battery.

[0062] 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 motion of the balance wheel of the speed control mechanism 30. The power supply circuit 60 is a circuit including, for example, a capacitor, and stores power to drive the control circuit 44 based on the current rectified by the rectifier circuit 50.

[0063] [Overview of Brake Control] Next, an overview of the braking control will be described with reference to Figures 6 to 8. Figure 6 is a diagram illustrating the relationship between the operation of the balance wheel and the back electromotive force generated in the coil in this embodiment. In the upper graph of Figure 6, the vertical axis is the angular velocity of the balance wheel 31 [rad / s], and the horizontal axis is the measurement time [s]. In the middle graph of Figure 6, the vertical axis is the rotation angle of the balance wheel 31 [deg], and the horizontal axis is the measurement time [s]. In the lower graph of Figure 6, the vertical axis is the back electromotive force generated in the coil 43 [V], and the horizontal axis is the measurement time [s]. Furthermore, each graph shown in Figure 6 shows an example in which the movement of the balance wheel 31 (permanent magnet 41) was measured for 4 seconds.

[0064] Figure 7 is a circuit diagram showing an example of the circuitry of a mechanical clock. Figure 8 is a timing chart showing an example of braking control. The upper part of Figure 8 shows the voltage waveform generated in coil 43 when braking control is performed. Note that during the period when the electromagnetic brake DB is in operation, no back electromotive force is detected because coil 43 is short-circuited. In the upper part of Figure 8, for the sake of visibility, all waveforms of back electromotive force are shown as solid lines, but the back electromotive force is 0 during the period when the electromagnetic brake DB is in operation. The lower part of Figure 8 shows the detection timing of the detection signal DE, the output timing of the reference signal OS, and the operation timing of the electromagnetic brake DB. An electromagnetic brake is a braking force obtained by short-circuiting the first terminal O1 and the second terminal O2 of coil 43 to create a closed-loop state, and generating a magnetic field in a direction that opposes the change in magnetic flux generated in coil 43 as the permanent magnet 41 rotates.

[0065] In this embodiment, the braking circuit 80 controls the movement of the permanent magnet 41 by applying an electromagnetic brake DB, thereby controlling the movement of the balance wheel 31 and adjusting the rate. In Figure 6, the timing for applying the electromagnetic brake DB (rate adjustment timing) is shown in a band-shaped region. It is preferable that the electromagnetic brake DB is applied while avoiding periods when power generation is easily obtained. In particular, it is preferable that the brake DB is applied while avoiding periods that include the peak of power generation, such as the period when the permanent magnet 41 rotates in the positive direction from a rotation angle of 0° to 180°, and the period when it rotates in the reverse direction from 0° to -180°.

[0066] Next, the circuit configuration in this embodiment will be described with reference to Figure 7.

[0067] As shown in Figure 7, transistors TP1 and TP2 are connected to the first terminal O1 and second terminal O2 of the coil 43, respectively. The back electromotive force generated in the coil 43 is input to transistors TP1 and TP2, and the rotation detection circuit 45 detects a detection signal based on this. By turning on transistors TP1 or TP2 at a predetermined timing, the induced voltages generated at the first terminal O1 and second terminal O2 corresponding to those transistors can be extracted as a voltage signal, which is a detection signal. Specifically, when detecting a positive back electromotive force, it is preferable to turn transistor TP1 OFF and transistor TP2 ON. On the other hand, when detecting a negative back electromotive force, it is preferable to turn transistor TP1 ON and transistor TP2 OFF.

[0068] Furthermore, transistors P11 and P12 are connected to the first terminal O1 of coil 43, and transistors P21 and P22 are connected to the second terminal O2 of coil 43. Transistors P11, P12, P21, and P22 are controlled ON / OFF by speed control pulses from the speed control pulse output circuit 46. During power generation, the gate terminals of transistors P11, P12, P21, and P22 are turned OFF. At this time, it is also preferable that the braking circuit 80 does not generate braking force. That is, it is preferable to turn OFF transistors DB1 and DB2, which will be described later. In that state, the rectifier circuit 50 is formed by transistors TP1 and TP2 and diode D. As the permanent magnet 41 rotates in forward and reverse directions, current flows through coil 43 and capacitor C is charged. When a certain amount of charge is stored in capacitor C, the power supply circuit 60 is started. Then, when the power supply circuit 60 is activated, the control circuit 44 is activated, and the control circuit 44 controls each circuit included in the rate adjustment means 40.

[0069] Furthermore, transistor DB1 is connected to the first terminal O1 of coil 43, and transistor DB2 is connected to the second terminal O2 of coil 43. Transistors DB1 and DB2 constitute the damping circuit 80 shown in Figure 5. The damping circuit 80 is a circuit that generates a damping force that reduces the vibration frequency of the permanent magnet 41 by short-circuiting the first terminal O1 and the second terminal O2. In Figure 5, the damping circuit 80 is shown as being included as part of the rate adjustment means 40, but it is not limited to this configuration.

[0070] In the example shown in the lower part of Figure 8, the electromagnetic brake DB with an operating period of b1 is activated when time tb1 has elapsed since the detection signal DE was detected. Furthermore, the electromagnetic brake DB is activated each time the detection signal DE is detected. Note that Figure 8 shows an example where the reference signal OS is set to a 1-step (1-second) reference, but it is not limited to this. That is, the reference signal OS may be output to a 2-step (2-second) or 3-step (3-second) reference. In this case, it is preferable to generate a reference signal OS that is output approximately every 2000 [ms] or approximately every 3000 [ms] by dividing the oscillation signal based on the crystal oscillator 70.

[0071] Furthermore, a non-detection period may be provided in which the detection signal DE is not detected regardless of the waveform of the back electromotive force V generated in the coil 43. The non-detection period should be a period in which the detection signal DE is not detected regardless of whether the back electromotive force V is equal to or greater than the threshold Vth. The non-detection period should ideally start after a predetermined period has elapsed since the detection of the detection signal DE. The non-detection period should ideally not overlap with the timing in which the maximum value of the back electromotive force V is detected. This makes it possible to ensure power generation while suppressing the false detection of peaks other than the maximum value of the back electromotive force V, even when the threshold Vth is set low.

[0072] Note that the speed control pulse output circuit 46, as explained with reference to Figures 5 and 7, is not essential. In other words, rate adjustment may be achieved solely by the electromagnetic brake DB provided by the braking circuit 80. Also, while Figure 7 shows a circuit configuration in which the rotation detection circuit 45 is connected to the first terminal O1 and capable of detecting a positive back electromotive force, it is not limited to this, and the rotation detection circuit 45 may also be capable of detecting a negative back electromotive force. In this case, it is preferable that the rotation detection circuit 45 is also connected to the second terminal O2.

[0073] [Braking control in this embodiment] Next, the details of the braking control in this embodiment will be described with reference to Figures 9 to 11. Figure 9 is a diagram showing an example of the duration of operation of the electromagnetic brake at each braking rank in this embodiment. Figures 10 and 11 are diagrams showing an example of the progression of the braking rank in this embodiment.

[0074] The thin solid lines shown in the upper graphs of Figures 10 and 11 indicate the progression of the braking rank in high braking mode. Specifically, Figure 10 shows an example where the braking rank in high braking mode progresses as follows: 12, 11, 11, 10, 10, 11, 10, 10, 10, 10, 10, when the number of detections of rate deviation is 0 to 9.

[0075] The thin dotted lines in the upper graphs of Figures 10 and 11 show the progression of the braking rank in low braking mode. Specifically, Figure 10 shows an example where the braking rank in low braking mode progresses as follows: 2, 2, 3, 3, 4, 4, 4, 3, 2, 3, when the number of detections of rate deviation is 0 to 9.

[0076] The thick solid lines in the upper graphs of Figures 10 and 11 indicate the braking ranks that were applied. Specifically, Figure 10 shows an example where the electromagnetic brake DB corresponding to braking ranks 12, 2, 11, 3, 10, 11, 4, 3, 2, and 10 was applied in this order when the number of detections of rate deviation was 0 to 9.

[0077] The lower graphs in Figures 10 and 11 show the progression of rate deviation. In the lower graphs in Figures 10 and 11, when the rate is advancing, the period difference t (deviation amount) is positive, and when the rate is lagging, the period difference t (deviation amount) is negative.

[0078] First, as a basic principle of braking control, when the rate is ahead, the braking rank should be increased, and when the rate is behind, the braking rank should be decreased. In other words, when the rate is ahead, the rate deviation is reduced by applying a large braking force, and when the rate is behind, the rate deviation is reduced by applying a small braking force or no braking force at all. When the rate is ahead, it is when the detection timing of the detection signal DE is earlier than the reference signal OS. When the rate is behind, it is when the detection timing of the detection signal DE is later than the reference signal OS.

[0079] In this embodiment, the braking circuit 80 is configured to apply a braking force corresponding to the currently set braking rank from among a plurality of braking forces corresponding to each of a plurality of braking ranks. Specifically, the braking circuit 80 is configured to apply electromagnetic brake DBs of ranks 0 to 14. The operating period of the electromagnetic brake DB at rank 14 is the longest, and the operating period becomes shorter as the rank decreases. That is, the braking force of the electromagnetic brake DB at rank 14 is the largest, and the braking force becomes smaller as the rank decreases. In this embodiment, the operating period of the electromagnetic brake DB at rank 0 is set to 0. That is, the braking force of the electromagnetic brake DB at rank 0 is set to 0.

[0080] The upper part of Figure 9 shows the operating period of the electromagnetic brake for ranks 0 to 4. The lower part of Figure 9 shows the operating period of the electromagnetic brake for ranks 10 to 14. In this embodiment, a braking period tc is set in advance for which the electromagnetic brake DB can be applied. The braking period tc is the period that begins after the detection signal DE is detected and after waiting for the first waiting period tp. The first waiting period tp is constant regardless of the rank of the electromagnetic brake.

[0081] The electromagnetic brake DB starts its operation after a second waiting period ts, which is determined by the rank, following the start of the braking period tc. For example, as shown in the upper part of Figure 9, in rank 1, the electromagnetic brake DE starts operating when the first waiting period tp and the second waiting period ts1 have elapsed after the detection signal DE is detected. Then, in rank 1, the operation period of the electromagnetic brake DE ends when the braking period tc has elapsed. Similar control is performed in other ranks, with the second waiting period ts becoming shorter as the rank increases. In other words, the operation period of the electromagnetic brake DB becomes longer as the rank increases. In this embodiment, the waiting period in rank 14 is set to 0. That is, in rank 14, the electromagnetic brake DE starts operating when the first waiting period tp has elapsed after the detection signal DE is detected.

[0082] The braking period tc, the first waiting period tp, and the second waiting period ts may be set arbitrarily in advance according to the specifications of the mechanical clock 1.

[0083] Furthermore, in the example in Figure 9, the end of the operating period of the electromagnetic brake DB coincides with the end of the braking period tc, but this is not the only option. For example, the start of the operating period of the electromagnetic brake DB and the start of the braking period tc may be made coincide, and the end of the operating period of the electromagnetic brake relative to the end of the braking period tc may be made variable according to the rank. Also, in the example in Figure 9, the end point of the operating period of the electromagnetic brake DB is fixed and the start point is varied according to the rank, but this is not the only option. For example, the start point of the operating period of the electromagnetic brake DB may be fixed and the end point may be varied according to the rank. Furthermore, it may be possible to switch between varying the start point and the end point of the operating period depending on the magnitude of the braking rank. In addition, the start and end points of the operating period may not be fixed, and the operating period may be varied based on a predetermined timing. Specifically, for example, the operating period may be varied so that it becomes longer before and after a predetermined timing each time the rank increases. Furthermore, the electromagnetic brake DB is not limited to a continuously applied full pulse, but may also be an intermittently applied chopper pulse.

[0084] In this case, the rate of the mechanical clock 1 will gradually deviate slightly with continuous use, and this will accumulate to result in a large rate deviation. The cause of rate deviation is not limited to continuous use; for example, it can occur when the position of the mechanical clock 1 changes or when it is subjected to an external shock. When a large rate deviation occurs in such a short time, it is difficult to adjust it quickly and accurately. For example, if the rate has advanced significantly due to a momentary external shock, it is advisable to apply a large electromagnetic brake DB in the braking control. However, if a large electromagnetic brake DB is applied, and that braking force is excessively large, the advanced rate will slow down significantly. If an even smaller electromagnetic brake DB is then applied in that state, and that braking force is excessively small, the slowed rate will advance. Therefore, in the mechanical clock 1 according to this embodiment, a configuration is adopted that allows for quick and accurate rate adjustment even when a large rate deviation occurs.

[0085] In this embodiment, the control circuit 44 is configured to switch between a high braking mode and a low braking mode depending on the detection timing of the detection signal DE relative to the output timing of the reference signal of the reference signal source. The current braking rank in the high braking mode is set to a higher braking rank than the current braking rank in the low braking mode. In other words, in this embodiment, the high braking mode is always set to a higher braking rank than the braking rank in the low braking mode.

[0086] In this embodiment, the braking mode is switched if the sign of the rate deviation reverses between the time of the previous detection and the time of the current detection. Specifically, if the rate was ahead when the rate deviation was detected in the previous detection and is behind when the rate deviation is detected in the current detection, the braking mode is switched from high braking mode to low braking mode. Also, if the rate was behind when the rate deviation was detected in the previous detection and is ahead when the rate deviation is detected in the current detection, the braking mode is switched from low braking mode to high braking mode.

[0087] Furthermore, the control circuit 44 sets the current braking rank in high braking mode and low braking mode according to whether the rate was ahead or behind when the rate deviation was detected last time, and whether the rate was ahead or behind when the rate deviation was detected this time.

[0088] Specifically, if the rate was advanced when the rate deviation was detected last time, and is advanced when the rate deviation is detected this time, the current braking rank in high braking mode will be increased by 1. Also, if the rate was lagging when the rate deviation was detected last time, and is advanced when the rate deviation is detected this time, the current braking rank in low braking mode will be increased by 1.

[0089] Furthermore, if the rate was advanced when the rate deviation was detected last time, and is lagging when the rate deviation is detected this time, the current braking rank in high braking mode will be lowered by 1. Also, if the rate was lagging when the rate deviation was detected last time, and is lagging when the rate deviation is detected this time, the current braking rank in low braking mode will be lowered by 1.

[0090] In the example shown in Figure 10, when the rate deviation is detected for the fourth time, the rate is significantly ahead, so high braking mode is activated, and the braking rank is 10. As a result, when the rate deviation is detected for the fifth time, the amount of deviation has decreased slightly, but it is still ahead. Therefore, the current braking rank of high braking mode is increased by 1, and high braking mode is continued. In other words, after the detection of the rate deviation for the fifth time, the electromagnetic brake DB corresponding to braking rank 11 is applied. In this way, adjustments are made to slow down the rate that is ahead.

[0091] In the example shown in Figure 10, the rate is significantly behind at the sixth detection of rate deviation. Therefore, the system switches from high braking mode to low braking mode and applies the electromagnetic brake DB corresponding to braking rank 4. At the seventh detection of rate deviation, the rate is still behind. Therefore, the current braking rank in low braking mode is lowered by 1, and low braking mode continues to be executed. In other words, after the seventh detection of rate deviation, the electromagnetic brake DB corresponding to braking rank 3 is applied. This adjusts the system to advance the lagging rate.

[0092] In high braking mode, if the current braking rank has reached the maximum rank, it is best to maintain the rank without increasing it further. Similarly, if the current braking rank has reached the minimum rank in low braking mode, it is best to maintain the rank without decreasing it further.

[0093] In the example shown in Figure 11, when the second rate deviation is detected, the rate is advanced, so high braking mode is activated. The braking rank at this time is 14. When the third rate deviation is detected, the rate is also advanced. However, since the current braking rank in high braking mode was already at its maximum at the time of the previous detection, the current braking rank remains 14 even after the third rate deviation is detected.

[0094] Furthermore, it is desirable that the braking rank in high braking mode and the braking rank in low braking mode always be different from each other. In other words, it is desirable that the current braking rank in high braking mode and the current braking rank in low braking mode be different from each other. Therefore, if the current braking rank in high braking mode is lowered, and the current braking rank in high braking mode after the lowering becomes the same as the current braking rank in low braking mode, it is desirable to maintain the braking rank in high braking mode. Also, if the current braking rank in low braking mode is raised, and the current braking rank in low braking mode after the raising becomes the same as the current braking rank in high braking mode, it is desirable to maintain the braking rank in low braking mode.

[0095] In the example shown in Figure 11, the braking rank in low braking mode is 11 at the time of the sixth detection of rate deviation. At this time, the braking rank in high braking mode is 12. The rate is lagging at the time of the sixth detection of rate deviation, and is advancing at the time of the seventh detection of rate deviation. Therefore, it would be good to increase the current braking rank in low braking mode, but in that case, the current braking rank in low braking mode will become the same as the current braking rank in high braking mode. Thus, the current braking rank in low braking mode is maintained at the time of the seventh detection.

[0096] In the example shown in Figure 11, the rate is advanced when the 7th rate deviation is detected, and lagging when the 8th rate deviation is detected. Therefore, it would be good to lower the current braking rank in high braking mode, but in that case, the current braking rank in high braking mode will be the same as the current braking rank in low braking mode. Thus, the braking rank in high braking mode is maintained at the time of the 8th detection.

[0097] Furthermore, the braking ranks for high braking mode and low braking mode when the number of detections of rate deviation is 0 may be set arbitrarily. Figure 10 shows an example where the braking rank for high braking mode is 12 and the braking rank for low braking mode is 2 when the number of detections is 0.

[0098] In this embodiment described above, the rate can be adjusted quickly and accurately by precisely controlling the braking rank according to the progression of rate deviation. In particular, even when the rate deviates significantly in a short period of time, such as when an external impact occurs, the rate can be adjusted quickly and accurately.

[0099] [flowchart] Next, the processing flow of braking control in this embodiment will be described with reference to Figure 12. Figure 12 is a flowchart showing an example of braking control in this embodiment.

[0100] In this embodiment, the power supply circuit 60 is activated by the movement of the permanent magnet 41, which generates electricity (ST1 Y). After a back electromotive force of Vth or higher is generated, that is, after the rotation detection circuit 45 detects the detection signal DE (ST2 Y), braking control is started.

[0101] The control circuit 44 calculates the time difference t between the detection signal DE and the reference signal OS (the amount of deviation in the detection timing of the detection signal DE relative to the output timing of the reference signal OS) (ST3). It is determined whether the time difference t is positive or zero, that is, whether the rate is advanced or not (ST4).

[0102] If the time difference t is determined to be positive or 0 (Y in ST4), it is determined whether the time difference t was negative at the time of the previous detection of rate deviation, that is, whether the rate was running slow at the time of the previous detection of rate deviation (ST5).

[0103] If the rate was slow when the rate deviation was detected last time (ST5, Y), it is determined whether increasing the braking rank in low braking mode will result in the same braking rank as the current braking rank in high braking mode (ST6). If it is determined that they will be the same (ST6, Y), the electromagnetic brake DB corresponding to the current braking rank in high braking mode is applied without changing the rank (ST7). On the other hand, if it is determined that they will not be the same (ST6, N), the braking rank in low braking mode is increased by 1 (ST8), and the electromagnetic brake DB corresponding to the current rank in high braking mode is applied (ST7).

[0104] If the rate was advanced when the rate deviation was detected last time (ST5, N), it is determined whether increasing the braking rank in high braking mode will cause the braking rank in high braking mode to exceed the maximum rank (ST9). If it is determined that it will exceed the maximum rank (ST9, Y), the electromagnetic brake DB corresponding to the current braking rank in high braking mode is applied without changing the rank (ST7). On the other hand, if it is determined that it will not exceed the maximum rank (ST9, N), the braking rank in high braking mode is increased by 1 (ST10), and the electromagnetic brake DB is applied at the current braking rank in high braking mode after the rank increase (ST7).

[0105] In ST4, if the time difference t is determined to be negative (ST4 N), it is determined whether the time difference t at the time of the previous detection of rate deviation was positive or zero, that is, whether the rate had advanced at the time of the previous detection of rate deviation (ST11).

[0106] If the rate was advanced when the rate deviation was detected last time (ST11 Y), it is determined whether lowering the braking rank in high braking mode will result in the same braking rank as the current braking rank in low braking mode (ST12). If it is determined that they will be the same (ST12 Y), the electromagnetic brake DB corresponding to the current braking rank in high braking mode is applied without changing the rank (ST13). On the other hand, if it is determined that they will not be the same (ST12 N), the braking rank in high braking mode is lowered by 1 (ST14), and the electromagnetic brake DB corresponding to the current braking rank in low braking mode is applied (ST13).

[0107] If the rate was slow when the rate deviation was detected last time (ST11 N), it is determined whether lowering the braking rank in low braking mode would cause the braking rank in low braking mode to fall below the minimum rank (ST15). If it is determined that it does fall below the minimum rank (ST15 Y), the electromagnetic brake DB corresponding to the current braking rank in low braking mode is applied without changing the rank (ST13). On the other hand, if it is determined that it does fall below the minimum rank (ST15 N), the rank in high braking mode is lowered by 1 (ST16), and the electromagnetic brake DB corresponding to the current rank in low braking mode is applied (ST13).

[0108] [Differentiation] Next, with reference to Figure 13, the details of the braking control in a modified example of this embodiment will be described. Figure 13 is a diagram showing an example of the transition of the braking rank in a modified example of this embodiment.

[0109] In the above embodiment, it is determined whether or not to change the braking rank each time a rate deviation is detected, but it is not limited to this. If the rate is advanced for a predetermined number of consecutive times, or if the rate is lagging for a predetermined number of consecutive times, the current braking rank may be maintained without being changed.

[0110] In the modified example, if the rate of motion is advanced three times in a row, the current braking rank in both the high braking mode and the low braking mode is maintained. In Figure 13, the rate of motion is advanced from 0 to 6 detection counts. Therefore, the current braking rank in the high braking mode is maintained at 12 from 0 to 2 detection counts. After that, the current braking rank in the high braking mode is raised to 13. Even then, the rate of motion is advanced from 3 to 5 detection counts. Therefore, the current braking rank in the high braking mode is maintained at 13 from 3 to 5 detection counts.

[0111] In the modified example, excessive braking force is suppressed, preventing the balance wheel 31 from stopping unintentionally.

[0112] [others] In the above embodiment and its modifications, an example has been described in which the braking rank can be switched within the range of 0 to 14, but it is not limited to this. Furthermore, a unique braking rank may be set for the high braking mode and the low braking mode. That is, the range of the braking rank and the braking force corresponding to the braking rank may differ between the high braking mode and the low braking mode.

[0113] Furthermore, while the above embodiment and its modifications show an example where the braking rank is raised or lowered by 1 each time rotation is detected, the invention is not limited to this. That is, the range of variation in the braking rank is not limited to 1 rank. For example, the braking rank may be raised or lowered by 2 each time rotation is detected. Specifically, for example, if the time difference t is less than or equal to a predetermined difference, the rank may be raised or lowered by 1 rank, and if the time difference t is greater than the predetermined difference, the rank may be raised or lowered by 2 ranks.

[0114] Furthermore, the range of variation of the braking rank may be made variable according to the difference between the previous time difference t and the current time difference t. For example, if the difference between the previous time difference t and the current time difference t is small, the range of variation of the braking rank should be increased, and if the difference between the previous time difference t and the current time difference t is large, the range of variation of the braking rank should be decreased. This makes it possible to quickly suppress the deviation in the rate even if a large deviation in rate occurs due to a sudden temperature change or a large shock. As a result, the display of an incorrect time for a long period of time will not be made, and a highly accurate time display can be provided in the mechanical watch 1.

[0115] Furthermore, while the above embodiment and its modifications describe an example in which a high braking mode and a low braking mode can be switched, the invention is not limited to this. That is, the control circuit 44 is preferably configured to switch the braking rank according to the detection timing of the detection signal DE relative to the output timing of the reference signal OS. The control circuit 44 is preferably configured to control the braking rank such that the range of variation in the braking rank is larger when the detection timing of the detection signal DE relative to the output timing of the reference signal OS is different than when either the detection timing of the detection signal DE relative to the output timing of the reference signal OS is consecutive between the previous detection of the detection signal DE by the rotation detection circuit 45 and the current detection of the detection signal DE, compared to when either the detection timing of the detection signal DE is consecutive between the previous and current detections. For example, when either the detection timing is consecutive between the previous and current detections, the braking rank may be raised or lowered by 1 or 2 ranks, and when the detection timing is different between the previous and current detections, the braking rank may be raised or lowered by 3 or more ranks.

[0116] Furthermore, manufacturing variations during the assembly of the mechanical clock 1, and positional adjustments of the balance wheel 31 by the support member 33 during the shipping inspection, may cause the range of rotation angle of the balance wheel 31 to differ between the forward and reverse directions. If the range of rotation angle of the balance wheel 31 differs between the forward and reverse directions, the timing at which the detection signal DE is detected will differ between the forward and reverse directions, even if the same braking force is applied. For this reason, different braking rank settings may be applied to the forward rotation and the reverse rotation of the balance wheel 31. Specifically, it is preferable to enable switching between a first high braking mode and a first low braking mode based on the detection signal DE detected by the forward rotation of the balance wheel 31, and to enable switching between a second high braking mode and a second low braking mode based on the detection signal DE detected by the reverse rotation of the balance wheel 31. The range of selectable braking ranks may be the same for the first high braking mode and the second high braking mode, but it is preferable that the current braking rank is set independently for each mode. The same applies to the first low braking mode and the second low braking mode.

[0117] Furthermore, although the above embodiment and its modifications describe an example in which braking force is applied by an electromagnetic brake DB, the invention is not limited to this, and the braking force may be provided by a speed control pulse output from a speed control pulse output circuit 46. That is, the speed control pulse output circuit 46 may control the movement of the balance wheel 31 and adjust the rate by braking the movement of the permanent magnet 41 by outputting a speed control pulse. In this case, it is preferable that a braking rank corresponding to the output period of the speed control pulse be set. Note that the rate adjustment (braking control) by the speed control pulse may include control to energize the coil 43 so that torque acts in the direction of accelerating the movement of the permanent magnet 41. That is, a braking rank in which the braking force is negative may be set. In this case, it is preferable that the braking rank of negative braking force be included in the low braking mode.

[0118] Furthermore, in the above embodiment and its modifications, an example was described in which the rate is determined to be ahead or behind based on whether the detection timing of the detection signal DE is ahead or behind, using the output timing of the reference signal OS as the reference timing. However, the criterion for whether the detection signal DE is ahead or behind is not limited to the output timing of the reference signal OS. That is, it is also possible to determine whether the detection timing of the detection signal DE is ahead or behind a predetermined reference timing corresponding to the output timing of the reference signal OS. In other words, the detection signal DE being ahead or behind may mean that the difference between the output timing of the reference signal OS and the detection timing of the detection signal DE is ahead or behind a predetermined value. That is, the predetermined reference timing may be a timing that is ahead or behind by a predetermined time from the output timing of the reference signal OS. Also, the predetermined reference timing is not limited to a specific moment in time, but may be a period with a predetermined width. If the reference timing is a period with a predetermined width, the detection timing may be included within the period of the reference timing, in which case it is preferable to perform control by considering the period difference t=0 in the above embodiment and its modifications. In the above embodiment and its modifications, the case of a period difference t=0 was treated the same as the case of a positive period difference for control purposes. However, the system is not limited to this, and a new rank variation mode may be provided for the case of a period difference t=0. For example, in the case of a period difference t=0, the rank of the low braking mode or high braking mode may not be varied, and braking may be performed at a rank intermediate between the low braking mode and the high braking mode.

[0119] Furthermore, the rate adjustment means 40 obtains a detection signal based on the operation of the bipolar magnetized permanent magnet 41, and if there are materials that have a magnetic influence around the permanent magnet 41, the detection accuracy may decrease. For this reason, it is advisable to use materials that have little magnetic influence for the materials surrounding the permanent magnet 41. For example, resin materials can be used for the support member 33 and the whisker holder 34. Also, phosphor bronze or brass can be used for the fastener 33a that fixes the support member 33 to the base plate 10. In addition, resin materials, aluminum, or brass can be used for the balance wheel 31.

[0120] Furthermore, as mentioned above, by making the hairspring 32 out of resin to reduce Young's modulus, the magnetic influence on the permanent magnet 41 can be reduced compared to the case where it is made of metal. Also, if the hairspring 32 is made of a magnetic metal, it may be affected by the magnetic influence of the permanent magnet 41, causing displacement of the shape and position of the hairspring 32. In this embodiment, by making the hairspring 32 out of resin, the shape and position of the hairspring 32 itself can be stabilized. In addition, an anti-magnetic plate made of a magnetic material may be provided on the mechanical watch 1 separately. This suppresses disturbances in the forward and reverse rotational motion of the permanent magnet 41 (balance wheel 31) even when an external magnet approaches the mechanical watch 1, and enables stable braking control. [Explanation of symbols]

[0121] 1 Mechanical watch, 2 Winding stem, 10 Base plate, 10a Positioning pin, 10b Aperture, 11 Power mainspring, 12 Gear train, 122 Second wheel, 123 Third wheel, 124 Fourth wheel, 13 Hand shaft, 131 Second hand, 20 Escapement mechanism, 21 Escape wheel, 22 Lever, 221 411, n12, n21, n22 notches.

Claims

1. Power source and A regulating mechanism including a balance wheel driven by power from the aforementioned power source, and a hairspring that elastically deforms to cause the balance wheel to rotate in forward and reverse directions, A bipolarized permanent magnet that rotates in the forward and reverse directions in conjunction with the forward and reverse rotational motion of the aforementioned balance wheel, Coil and, A rotation detection circuit that detects a detection signal based on a detection voltage generated in the coil due to the movement of the permanent magnet accompanying the forward and reverse movement of the balance wheel, A rate adjustment means for braking the aforementioned permanent magnet, which applies a braking force corresponding to the currently set braking rank from among a plurality of braking forces corresponding to each of a plurality of braking ranks, Includes, The rate adjustment means includes a control circuit for controlling the braking rank, The aforementioned control circuit is The braking rank is configured to be switchable according to the detection timing of the detection signal relative to a predetermined reference timing corresponding to the output timing of the reference signal of the reference signal source. The braking rank is controlled such that the range of variation in the braking rank is larger when the detection timing is ahead or behind the reference timing compared to the reference timing, compared to when the previous detection of the detection signal by the rotation detection circuit and the current detection of the detection signal, than when either the detection timing is ahead or behind the reference timing is continuous. Mechanical watch.

2. The control circuit is configured to switch between a high braking mode and a low braking mode depending on the detection timing relative to the reference timing. The current braking rank in the high braking mode is set to a higher braking rank than the current braking rank in the low braking mode. The mechanical clock according to claim 1.

3. The rate adjustment means includes a braking circuit that applies a braking force to the permanent magnet by short-circuiting the terminals of the coil. The mechanical clock according to claim 2.

4. The aforementioned braking circuit is When the rotation detection circuit detects the detection signal, if the detection timing is ahead of the reference timing, the braking force corresponding to the current braking rank in the high braking mode is applied. When the rotation detection circuit detects the detection signal, if the detection timing is delayed compared to the reference timing, the braking force corresponding to the current braking rank in the low braking mode is applied. The mechanical clock according to claim 3.

5. The control circuit sets the current braking rank in the high braking mode and the low braking mode based on the detection timing of the previous detection signal relative to the reference timing. The mechanical clock according to claim 4.

6. The aforementioned control circuit is When the rotation detection circuit detects the current detection signal, if the detection timing is ahead of the reference timing, and when the rotation detection circuit detected the previous detection signal, if the detection timing was behind the reference timing, Switching from the low braking mode to the high braking mode, The mechanical clock according to claim 2.

7. The control circuit switches from the low braking mode to the high braking mode and increases the current braking rank in the low braking mode. The mechanical clock according to claim 6.

8. The aforementioned control circuit is If the current braking rank in the low braking mode is increased, and the current braking rank in the low braking mode after the increase is different from the current braking rank in the high braking mode, Switching from the low braking mode to the high braking mode, and increasing the current braking rank in the low braking mode, If the current braking rank in the low braking mode is increased, and the current braking rank in the low braking mode after the increase becomes the same as the current braking rank in the high braking mode, Switching from the low braking mode to the high braking mode, while maintaining the braking rank in the low braking mode. The mechanical clock according to claim 6.

9. The aforementioned control circuit is When the rotation detection circuit detects the current detection signal, if the detection timing is ahead of the reference timing, and when the rotation detection circuit detected the previous detection signal, if the detection timing was ahead of the reference timing, To increase the current braking rank in the aforementioned high braking mode, The mechanical clock according to claim 2.

10. The aforementioned control circuit is When the rotation detection circuit detects the current detection signal, if the detection timing is delayed relative to the reference timing, and when the rotation detection circuit detected the previous detection signal, if the detection timing was advanced relative to the reference timing, Switching from the high braking mode to the low braking mode, The mechanical clock according to claim 2.

11. The control circuit switches from the high braking mode to the low braking mode and also lowers the current braking rank in the high braking mode. The mechanical clock according to claim 10.

12. The aforementioned control circuit is If the current braking rank in the high braking mode is reduced, and the current braking rank in the high braking mode after the reduction is different from the current braking rank in the low braking mode, Switching from the high braking mode to the low braking mode, and lowering the braking rank in the high braking mode, If the current braking rank in the high braking mode is reduced, and the current braking rank in the high braking mode after the reduction becomes the same as the current braking rank in the low braking mode, Switching from the high braking mode to the low braking mode, while maintaining the braking rank in the high braking mode. The mechanical clock according to claim 10.

13. The aforementioned control circuit is When the rotation detection circuit detects the current detection signal, if the detection timing is delayed relative to the reference timing, and when the rotation detection circuit detected the previous detection signal, if the detection timing was delayed relative to the reference timing, To lower the current braking rank in the aforementioned low braking mode, The mechanical clock according to claim 2.

14. The control circuit maintains the braking rank during a predetermined period if the detection timing is ahead of the reference timing for a predetermined number of consecutive times, or if the detection timing is behind the output timing for a predetermined number of consecutive times, and then sets the braking rank based on the detection timing of the current detection signal relative to the output timing. The mechanical clock according to claim 2.

Images