Oscillator control device and control method for mechanical timepieces with torque-limited electronic fusee control

Abstract

While suppressing torque fluctuations in the mainspring, it reduces mechanical losses and power consumption, achieving long-term rate stability. [Solution] In mechanical watches, It is equipped with a) a torque limiting mechanism that sets the average impulse amount from the mainspring to 80-95% of the reference value, b) an electronic actuator that supplies the missing energy from a direction perpendicular to the main vibration axis in the zero-crossing section of the oscillator's angular velocity, and c) a control circuit that statistically controls the phase difference with an external reference clock.By reducing mechanical loss through torque limiting and efficiently supplying the missing amount, it achieves high precision with very little power and makes it possible to extend the drive time by up to 6-8 times with the same barrel.

Description

[Technical Field]

[0001] The present invention relates to a technique for controlling the amplitude and rate of an oscillator (balance) of a mechanical timepiece with high precision. In particular, it relates to an oscillator control device and control method that achieves high precision while reducing mechanical loss by intentionally limiting the torque of a mainspring and electronically replenishing any deficiency. [Background technology]

[0002] In conventional mechanical watches, a mainspring and escapement provide an impulse to an oscillator, maintaining its amplitude. However, the output torque of the mainspring fluctuates depending on the amount of winding and the surrounding environment, and the isochronism error caused by the change in amplitude disrupts the rate. Historically, a mechanical constant torque mechanism (fusé-and-chain mechanism) has been used to address this issue, but the complexity of the structure and the increasing number of parts make it difficult to adopt in modern wristwatches.

[0003] Mechanisms that gently replenish energy at the amplitude peak (zero angular velocity) are known for large pendulum clocks. Examples include Big Ben's double tripod gravity escapement (1859) and the Shortt-Synchronome free pendulum clock (1921). These reduce shock by "modestly injecting energy at the amplitude peak," but there remain challenges in applying them to wristwatch-sized clocks.

[0004] Patent Document 1 discloses a method for Q modulation or frequency modulation of a resonator as a technology for electronic control of a mechanical timepiece. However, this publication does not disclose a process for reducing mainspring torque, nor does it disclose the supply of insufficient energy by cross-axis coupling.

[0005] Seiko's Spring Drive (registered trademark) is a technology that generates electricity using the energy of a mainspring and regulates the speed using an electromagnetic brake. However, this is continuous speed control, which is fundamentally different from instantaneous energy injection at the zero crossing. Furthermore, Spring Drive does not reduce the torque of the mainspring; rather, it requires high torque to generate electricity.

[0006] Patent Document 2 describes a statistically driven rate stabilizing device that uses an external reference but does not directly inject mechanical vibrations into the balance, and is capable of stabilizing rate over a long period of time with extremely low power consumption, which is technology related to an earlier invention by the applicant of the present invention. However, there is no mention of intentionally limiting the torque of the mainspring and electronically replenishing the deficiency.

[0007] Patent Document 3 describes a technology related to an earlier invention by the applicant of the present invention, in which torque injection by cross-axis coupling is applied to a statistical drive rate stabilizer, and the tangential torque component is amplified even at the same voltage, thereby shortening the pulse width and contributing to power saving. However, there is no mention of intentionally limiting the torque of the mainspring and electronically replenishing the deficiency. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication WO2015 / 067059 [Patent Document 2] Patent application No. 2025-086063 [Patent Document 3] Patent application No. 2025-091587 Summary of the Invention [Problem to be solved by the invention]

[0009] The problem that this invention aims to solve is to suppress torque fluctuations in the mainspring without increasing the number of parts, reduce mechanical loss and power consumption, electronically replenish any deficiency, and achieve long-term rate stability. [Means for solving the problem]

[0010] In a first aspect of the present invention, there is provided an oscillator control device for a mechanical timepiece, comprising: a) a mechanical drive that imparts impulses to the oscillator via a spring and escapement system; b) a torque limiting mechanism that limits the average impulse amount supplied by the mechanical driving unit to the vibrator to 80% to 95% of a reference value required for the vibrator to maintain a steady amplitude; c) an electronic actuator that applies a force in a second axial direction perpendicular to the main vibration axis of the vibrator while the angular velocity of the vibrator is in a zero-cross section to compensate for the amount of energy that is lacking due to the torque limiting mechanism; d) a control circuit that statistically controls the electronic actuator based on a phase difference with respect to an external reference clock; A vibrator control device is provided, comprising: Here, statistical control refers to control that corrects the rate of the oscillator by statistically updating the injection probability P(t) (0≦P≦1), which is the probability of injecting energy, based on the phase difference between the external reference clock and the oscillator. Hereinafter, this type of statistical control will be referred to as "statistical control."

[0011] Here, the control circuit may perform at least one of continuous statistical control using proportional-integral control (hereinafter referred to as PI control), continuous statistical control using proportional-integral-derivative control (hereinafter referred to as PID control), continuous statistical control using a phase-locked loop (hereinafter referred to as PLL control), and discrete statistical control using ΔΣ modulation. Here, PI control is a control that detects the phase difference between the external reference clock and the oscillator, uses this phase difference as an input to PI control, and adjusts the injected energy to bring the oscillator's behavior closer to the oscillation of the target external reference clock. PID control is a control method that detects the phase difference between an external reference clock and an oscillator, uses this phase difference as an input to PID control, and adjusts the injected energy to bring the oscillator's behavior closer to the target oscillation of the external reference clock. A phase-locked loop is a loop that detects the phase difference between an external reference clock and an oscillator and continuously controls the phase difference through feedback. Discrete statistical control using ΔΣ modulation is a control method that sequentially updates the injection probability P(t) according to the sign and magnitude of the phase difference with an external reference oscillator, generates a drive waveform using a ΔΣ 1-bit modulator, and performs rate correction by turning the external pulse force injection ON / OFF.

[0012] The electronic actuator may be a piezoelectric element, an electrostatic actuator, or a MEMS mechanical actuator, and the torque limiting mechanism may be formed by a mechanical setting including at least one of the effective number of turns of the mainspring, the diameter of the barrel, or the shape of the pallet stone as a component.

[0013] The torque limiting may be configured to reduce mechanical loss by 20% or more, and the statistical control may be configured to realize control response characteristics that can achieve an accuracy of within ±1 second per day in the frequency range of 1 Hz to 4 Hz.

[0014] In a second aspect of the present invention, there is provided a method for controlling an oscillator of a mechanical timepiece, comprising: a) limiting the average impulse amount of the mainspring and escapement system to between 80% and 95% of the reference value required for the oscillator to maintain a steady amplitude; b) electronically supplying energy from a direction perpendicular to the main vibration axis while the angular velocity of the vibrator is in a zero-cross section; c) statistically controlling the energy replenishment based on a phase difference with respect to an external reference clock; A vibrator control method is provided, comprising: [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing a state in which the vibrator control device of this embodiment is incorporated into the main body of a mechanical watch. [Figure 2] FIG. 2 is a schematic diagram showing the details of the mechanical energy source unit. [Figure 3] FIG. 3 is a schematic diagram showing the configuration and fixed arrangement of a pair of electronic actuators. [Figure 4] FIG. 4 is a functional block diagram showing the functional configuration of the control unit. [Figure 5] FIG. 5 is a flowchart showing a control flow in which the control of the injection probability P(t) of the control unit is placed in the main layer. [Figure 6] FIG. 6 is a flowchart showing the details of the normal mode operation in step A4. [Figure 7] FIG. 7 is a flowchart showing details of the ΔΣ 1-bit quantization mode operation B1 in the auxiliary layer in step A5. [Figure 8] FIG. 8 is a flowchart showing details of the low detune frequency hopping mode B2 in the auxiliary layer of step A5. DETAILED DESCRIPTION OF THE INVENTION

[0016] The object of the present invention is achieved by adopting a configuration in which the following three elements work together. (Element 1) Torque limit: The average impulse amount supplied by the mainspring to the oscillator is set to between 80% and 95% of the reference value required to maintain steady amplitude by adjusting the number of effective turns of the mainspring, the diameter of the barrel, or the shape of the pallet stone. This range was experimentally determined as the range that achieves optimal energy efficiency due to the nonlinear characteristics of mechanical loss. (Element 2) Zero-cross energy injection: While the angular velocity of the vibrator is in the zero-crossing section (the period when the sign of the angular velocity changes), energy is electronically injected from the direction of the second axis perpendicular to the main vibration axis. Since the kinetic energy is at its minimum during this period, the effect of the injected energy on the phase is minimized. (Element 3) Statistical Phase Control: The phase difference between the external reference clock and the oscillator is detected, and the oscillator phase is synchronized to the reference clock using statistical methods. Basically, continuous phase tracking using a PLL is used, but in advanced embodiments, discrete statistical control using ΔΣ modulation can also be selected.

[0017] The core of this invention is the cooperation of these three elements: torque limitation reduces mechanical loss, the deficiency is efficiently compensated for at zero crossing timing, and statistical phase control ensures long-term stability. It should be noted that the various values ​​shown in the examples are merely examples and are not limited to these values, but may be changed as appropriate. [Example]

[0018] FIG. 1 is a schematic diagram showing a state in which the oscillator control device of this embodiment is incorporated into a mechanical timepiece body 100. As shown in FIG. The vibrator control device of the present invention is configured as a system consisting of a mechanical energy source section 110, which is also a component of the mechanical watch body 100, a vibrator 120, which is also a component of the mechanical watch body, an actuator 130, a sensor 140, a control unit 150, an external reference clock 160, and a power supply section 170. An actuator 130 is attached to the vibrator 120. Reference numeral 121 denotes a hole stone of the vibrator 120, and 122 denotes a main vibration axis of the vibrator 120. An electronic auxiliary unit 130 consisting of two electronic actuators is arranged and fixed to the hole stone 121. The control unit 150 is electrically connected to the other components to receive detection signals, send control signals, and control the supply of power. The external reference clock 160 is an external transmitter that incorporates an oscillator that vibrates separately from the balance that constitutes the mechanical timepiece, and transmits a reference clock signal, which is the oscillation signal, to the control unit 150. The power supply unit 170 is made up of a button battery (1.55V), a DC-DC booster that boosts the voltage of the button battery to 10V, and a current monitor that monitors the average current I_avg.

[0019] FIG. 2 is a schematic diagram showing details of the mechanical energy source unit 110. As shown in FIG. The mechanical energy source unit 110 includes a mainspring 111, a barrel 112, and an escapement 113, which are also components of the mechanical timepiece body. The effective number of turns of the mainspring 111, the diameter of the barrel 112, or the shape of the pallet jewel 114 of the escapement 113 are adjusted to set the average impulse amount supplied to the oscillator 120 to between 80% and 95% of the reference value required for the oscillator to maintain a steady amplitude. The dotted circle 115 is an enlarged image of the area around the pallet stone. The escapement 113 is composed of an escape wheel 116 and a pallet fork 117 to which the pallet stone is fixed. As an example of adjusting the shape of the pallet stone 114, a method is adopted in which the angle of the surface 118 that comes into contact with the escape wheel is made shallower than usual.

[0020] The actuator 130 is arranged in a direction (defined as the X-axis) perpendicular to the vibrator's main vibration axis (defined as the Z-axis), and is composed of a pair of electronic actuators each having position vectors r1 and r2 as viewed from the main vibration axis. These electronic actuators can apply opposing forces F1 and F2 in the X-axis direction, and a rotational torque component about the main vibration axis is generated by the cross product of each force vector and the position vector. This minute vibration energy in the orthogonal direction is injected into the main vibration along the main vibration axis via mechanical cross-axis coupling.

[0021] FIG. 3 is a schematic diagram showing the configuration and fixed arrangement of a pair of electronic actuators. Two electronic actuators 301, 302 are fixed to the hole stone 121 of the vibrator 120 so as to sandwich both shoulders of the vibrator's main vibration axis 122, and the displacement axis of the actuators is set at a position where it abuts with a slight preload on the shoulder of the main vibration axis 122 at an inclination angle α (0°<α<90°) with respect to the XY plane, which is the rotation plane of the balance wheel. At the contact point with the main vibration axis 122, the electronic actuators 301 and 302 are displaced in the directions of their respective displacement axes 303 and 304 to apply a pulse external force.

[0022] (sensor) The sensor 140 is built into the mechanical timepiece body 100 , detects the vibration of the balance wheel of the oscillator 120 , and transmits a detection signal to the control unit 150 .

[0023] A CMOS optical motion sensor is used for sensor 140. The sensor used here pulse-drives a specified VCSEL (Vertical-Cavity Surface-Emitting Laser) and performs correlation calculations on the scattered light pattern with a light-receiving pixel array to obtain vibration data including the zero-crossing interval of the angular velocity and the frequency and amplitude of the balance wheel, and transfers the data to the control unit.

[0024] Table 1 shows the relationship between the angular velocity ω of the balance wheel of the oscillator and time t. The arrows marked on the time axis indicate the zero crossing intervals.

[0025] [Table 1]

[0026] (actuator) A multi-layer PZT stack is used as the piezoelectric element for the actuators 301 and 302. In response to the pulse external force command output by the control unit 150, a 2F0 band pulse external force is injected into the balance cock using the zero crossing interval as a drive trigger. Here, a piezoelectric element is used as the actuator, but the actuator that can be used in the present invention is not limited to this, and the following configurations are possible as specific implementations of the actuator: (1) Electrostatic comb system: A comb-shaped electrode manufactured using MEMS technology is placed under the balance. (2) Mechanical coupling method: A contact-type energy transmission configuration using a micro actuator made by MEMS.

[0027] (control unit) The operation of each functional component shown here is realized by executing a control program such as pre-installed firmware on a specified processor or dedicated hardware circuit, and by cooperating with various devices that constitute the device. The control unit 150 compares the phase of the oscillator with that of a reference clock from an external reference source 160, and achieves phase synchronization through continuous statistical control using PI control. When high accuracy is required, delta-sigma modulation can be selectively used, which encodes the phase difference into a 1-bit pulse train and shapes the quantization noise outside the operating band of the oscillator, thereby improving instantaneous phase accuracy. Here, continuous statistical control using PI control and discrete statistical control using ΔΣ modulation are adopted, but the controls that can be adopted in the present invention are not limited to these, and continuous statistical control using PID control, continuous statistical control using PLL control, etc. can be adopted as appropriate.

[0028] A microcontroller unit (hereinafter referred to as MCU) is used for the control unit 150. The MCU refers to an external reference, calculates the phase difference Δφ with respect to the balance phase, uses Δφ as an input for PI control, and controls the pulse width, amplitude, duty ratio, and phase of the pulse external force control profile output to the pulse generator so that Δφ becomes zero, thereby adjusting the injection energy.

[0029] FIG. 4 is a functional block diagram showing the functional configuration of the control unit. The control unit 150 is generally composed of a statistical drive control section 401 and a pulse generator 408 that outputs a pulse external force control command in accordance with a pulse control profile and a drive trigger generated by the statistical drive control section. The statistically driven control unit 401 comprises a phase difference Δφ calculation unit 402 , a probability P(t) update unit 403 , a ΔΣ Duty control unit 404 , a frequency table 405 , an I_avg & amplitude monitoring unit 406 , and a mode selection unit 407 .

[0030] The phase difference Δφ calculation unit 402 calculates the phase difference Δφ between the external reference signal and the vibration of the balance oscillator, and sends the result to the probability P(t) update unit 403 . The probability P(t) update unit 403 updates the injection probability P(t) in real time and transmits it to the pulse generator 408 .

[0031] The ΔΣ Duty control unit 404 quantizes and noise shapes the updated probability P(t) into a 1-bit drive trigger sequence d(n) by ΔΣ secondary modulation, and also generates a pulse control profile including the pulse width tp, amplitude Vp, etc. by referring to the frequency table 405, and sends it to the pulse generator. Additionally, real-time d(n) sequences are provided to the pulse generator 408 during initialization / recalibration of the pulse control profile.

[0032] The frequency table 405 stores the balance frequency (F0 and frequency after temperature correction) of the target mechanical timepiece, fine adjustment frequencies (F0+ΔF1, F0+ΔF2, ...), and frequencies of high-order synchronization trains (k·F0, k=2 to 10).

[0033] The I_avg & amplitude monitor 406 monitors the average current I_avg supplied from the power supply 170 and the vibration amplitude of the balance wheel acquired by the sensor, and provides feedback to the above-mentioned sections if any of the values ​​deviate from the allowable range. The mode selection unit 407 compares the average current I_avg with the rated current of the power supply block, and also compares the vibration amplitude of the balance wheel with the upper limit amplitude, and selects the operation mode of the control unit. The pulse generator 408 transmits a pulse external force control command to the actuator in accordance with the pulse control profile generated in the selected operation mode and the drive trigger of the zero crossing section (only the drive trigger when the pulse control profile is not generated).

[0034] FIG. 5 is a flowchart showing a control flow in which the control of the injection probability P(t) of the control unit is placed in the main layer. In step A1, the frequency F0 and amplitude associated with the movement of the balance wheel are measured by the sensor 140. In step A2, the fundamental excitation frequency is calculated and determined by the control unit as F0x 2 . In step A3, a reference clock signal is received from the external reference clock 160, the phase related to the operation of the balance wheel is estimated, and the phase difference Δφ from the reference frequency is calculated. In step A4, the control unit updates the injection probability P(t) in proportion to the phase difference Δφ, and performs core control (hereinafter referred to as normal mode operation) in which a pulse control profile and a drive trigger for the zero-crossing section are generated to inject a 2F0 band external force pulse into the balance cock with the injection probability P(t) set to P=0 when the amplitude upper limit A>A_max. In step A5, the control unit selects and activates the operation of the auxiliary layer, modulates the fundamental excitation frequency (2F0) in proportion to the calibration amount generated by the operation of the activated operating mode, performs phase conversion, and generates a pulse control profile and a drive trigger for the zero-crossing section.

[0035] Details of the action selection and activation of the auxiliary layer in step A5 are as follows. The power monitor and finite state machine (hereinafter referred to as FSM) of the power supply block 170, which measures the average current consumption I_avg, autonomously switch between ΔΣ1 bit stream mode operation B1 and low detune frequency hopping mode operation B2 depending on the I_avg threshold, and activate it.If not activated, the operation of step A5 is skipped, and the pulse control profile generated in step A4 and the drive trigger for the zero-crossing section are sent to the pulse generator. Here, a first threshold I1 and a second threshold I2 are set in descending order of power, the average current consumption I_avg is measured, and if I_avg is less than the first threshold I1, ΔΣ1 bitstream mode operation B1 is selected, and if I_avg is greater than I1 and less than the second threshold I2, low detune frequency hopping mode operation B2 is selected.

[0036] In the ΔΣ1 bit stream mode operation B1, the control unit quantizes the injection phase with a ΔΣ2-order loop (64 kHz) and drives the pulse generator with a 1 / 0 bit sequence. This is a rate correction mode in which rate correction is performed only with the average duty ratio D(t) based on the 1 bit stream generated by the ΔΣ modulator.

[0037] The low detune frequency hopping mode operation B2 is performed by the control unit: 2 This is an operation in which eight frequencies of F0±{-30,-20,-10,-5,+5,+15,+25,+30} ppm are hopped using a linear feedback shift register (hereinafter referred to as LFSR). This is a rate correction mode in which rate correction is performed by pseudo-randomly hopping multiple frequencies of ±ΔF_ppm centered on twice the balance's natural frequency F0.

[0038] In step A6, the control unit generates a pulse control profile and a drive trigger for the zero crossing section generated by the normal mode or the mode operation of the selected / activated auxiliary layer, and outputs them to the pulse generator.

[0039] In step A7, the pulse generator generates a pulse external force control command in accordance with the received pulse control profile and the drive trigger of the zero crossing section, and outputs the command to the actuator.

[0040] In step A8, the actuator applies a pulse external force to the main vibration axis of the vibrator in the zero cross section in accordance with the pulse external force control command.

[0041] In step A9, the control unit repeats the operations from step A1.

[0042] (Normal Mode Operation) Figure 6 is a flowchart showing the details of the normal mode operation of step A4. In step C1, the control unit acquires the reference frequency φ_ref from the reference clock signal from the external reference clock 160. Furthermore, the frequency φ_meas and amplitude A of the balance oscillator are acquired from the sensor 130. In step C2, the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas acquired by the sensor. In step C3, the control unit generates an injection probability P(t) proportional to the phase difference based on Equation 1. As shown in Equation 2, when the acquired amplitude A is within the upper amplitude limit, the injection probability P(t) is proportional to the phase difference Δφ, and when the amplitude upper limit is exceeded, the injection probability is set to 0.

[0043]

number

[0044]

number

[0045] In step C4, the control unit generates a pseudo-random number R(t) ranging from 0 to 1. In step C5, the control unit uses a comparator to compare the pseudo-random number R(t) with the injection probability P(t) based on Equation 3, determines whether to inject a pulse external force according to the comparison result, and quantizes the zero-crossing interval obtained as a drive trigger for injecting the external force pulse.

[0046]

number

[0047] When the auxiliary layer in step A5 is skipped, the pulse generator generates a pulse external force command according to the drive trigger quantized in the normal mode operation in step A4 and according to a preset pulse control profile, and outputs the pulse external force command to the actuator. The pulse control profile at this time is set as follows: The pulse width tp is set to approximately 2 ms (range 1.5 to 3 ms), the amplitude Vp to approximately 10 V (range 8 to 12 V), and the duty ratio D0 to 20 to 30%, and the same energy Ep is injected symmetrically in two windows of phase 0 degrees ±10 degrees and 180 degrees ±10 degrees. Here, the pulse width tp and amplitude V_p are fixed, the instantaneous energy Ep of each excitation pulse is kept constant, and the rate correction is performed only by the pulse injection phase. Alternatively, the control circuit may detect the pulse injection phase and change the injection probability P(t) in real time in proportion to the magnitude of the detected injection phase.

[0048] (ΔΣ 1-Bit Stream Mode Operation B1) Figure 7 is a flowchart showing details of ΔΣ 1-bit quantization mode operation B1 in the auxiliary layer in step A5. In step D1, the control unit acquires the reference frequency φ_ref from the reference clock signal from the external reference oscillator 160. In step D2, the balance oscillator frequency φ_meas and amplitude A are acquired from the sensor 130, and the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas acquired by the sensor. In step D3, the 64 kHz sampling second-order ΔΣ modulator in the ΔΣ Duty control unit quantizes the detected phase error Δφ into a 1-bit drive trigger sequence d(n), applies noise shaping, and performs high-resolution encoding of the phase error.

[0049] (Low Detune Frequency Hopping Mode B2) FIG. 8 is a flowchart showing details of the low detune frequency hopping mode B2 in the auxiliary layer in step A5.

[0050] In step E1, the control unit acquires the reference frequency φ_ref from the reference clock signal from the external reference clock 160. In step E2, the frequency φ_meas and amplitude A of the balance oscillator are acquired from the sensor 130, and the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas acquired by the sensor. In step E3, the control unit determines the probability P(t) using the phase difference Δφ, the injection probability average P_avg, and the FSM state, and converts it into a drive trigger sequence d(n). In step E4, the control unit generates a pseudorandom index (0-7) from a 15-bit LFSR. In step E5, the control unit determines the drive frequency by indexing the frequency table, and generates a pulse control profile that hops among eight frequencies in 2F0±{-30, -20, -10, -5, +5, +15, +25, +30} ppm, including pulse width tp, amplitude V_p, phase window ID, timer reload value, etc., and a drive trigger sequence d(n) for the zero-crossing interval, and sends these to the pulse generator.

[0051] The pulse generator receives the pulse control profile and drive trigger sequence d(n), generates a phase window mask of 0°±δ·180°±δ based on the drive frequency and phase window ID, and ANDs the phase window mask with the drive trigger sequence d(n) to determine whether to fire. It then outputs pulses according to tp·Vp in the pulse control profile at the permitted timing, supplying the specified number of pulses to the actuator within the hopping period T_h. Through the above steps and the operation of the pulse generator, pseudo-random hopping is performed within 2F0±ΔF_ppm (≦50 ppm).

[0052] The principle behind the present invention not increasing energy consumption will be explained below. In the case of a high Q value oscillator (Q = 3000 to 5000), the energy loss per cycle is only 2π / Q (approximately 0.1 to 0.2%) of the stored energy.

[0053] The energy loss when the oscillator's stored energy is 1 μJ is as follows. Based on the assumption of a high Q oscillator as described above, the loss per cycle is estimated to be 1 to 2 nJ, and the shortfall when the spring torque is set to 85% is 15% of the loss, calculated to be 0.15 to 0.3 nJ. This means that the auxiliary power required when the oscillation frequency is 4 Hz is 0.6 to 1.2 nW.

[0054] The effects of setting the spring torque to 85% of the reference value are as follows: (Effect 1) The impact speed of the impulse given to the vibrator by the mechanical energy source is reduced by 15%, resulting in a reduction of impact loss by approximately 30%. (Effect 2) A 15% reduction in friction in the escapement reduces friction loss by approximately 15%. (Effect 3) Viscous loss is reduced by approximately 30% due to a decrease in the oil film shear rate in the escapement. As a result of the above effects, the efficiency of the escapement increases from 25-30% to 35-45%, and the running time is extended by more than 1.5 times.

[0055] Furthermore, because the present invention guarantees accuracy through phase synchronization with an external reference clock, it is possible to reduce the frequency from the conventional 4 Hz to 1-2 Hz. At 1 Hz, it is possible to achieve the graceful stepping motion of the second hand of a mechanical watch. The combined effect of reduced vibration frequency and torque makes it possible to extend the drive time by up to 6 to 8 times with the same barrel.

[0056] By providing the above-described device, it is possible to achieve the following objectives. (a) Suppressing torque fluctuations without using a mechanical constant torque mechanism; (b) minimizing shock and wear caused by the escapement; (c) minimizing the power consumption of electronic aids; (d) Achieving long-term rate stability and high accuracy; (e) To extend the running time of existing mechanical watches while maintaining the basic structure of the watches. [Industrial Applicability]

[0057] This invention can be used in the field of high-end mechanical watches as a technology that achieves precision comparable to that of quartz watches while maintaining the traditional mechanical appeal. In particular, it dramatically improves practicality by significantly extending the running time with the same size barrel. Furthermore, the 1Hz operation allows the elegant step movement of the second hand to be enjoyed, creating new aesthetic value for mechanical watches. [Explanation of symbols]

[0058] 100 Mechanical watch body 110 Mechanical Energy Source Section 120 vibrator 130 Electronic auxiliary section 140 sensors 150 Control Unit 160 External Reference Clock 170 Power supply section

Claims

1. An oscillator control device for a mechanical timepiece, a) a mechanical drive that imparts impulses to the oscillator via a spring and escapement system; b) a torque limiting mechanism that limits the average impulse amount supplied by the mechanical driving unit to the vibrator to 80% to 95% of a reference value required for the vibrator to maintain a steady amplitude; c) an electronic actuator that applies a force in a second axial direction perpendicular to the main vibration axis of the vibrator while the angular velocity of the vibrator is in a zero-cross section to compensate for the energy amount lacking due to the torque limiting mechanism; d) a control circuit that statistically controls the electronic actuator based on a phase difference with respect to an external reference clock; A vibrator control device comprising:

2. The vibrator control device according to claim 1, characterized in that the control circuit performs at least one of continuous statistical control using proportional-integral control, continuous statistical control using proportional-integral-derivative control, continuous statistical control using a phase-locked loop, and discrete statistical control using delta-sigma modulation.

3. 3. The vibrator control device according to claim 1, wherein the electronic actuator is any one of a piezoelectric element, an electrostatic actuator, and a MEMS mechanical actuator, and the torque limiting mechanism is formed by a mechanical setting including at least one of the effective number of turns of a mainspring, the diameter of a barrel, and the shape of a pallet stone as a component.

4. 2. The vibrator control device according to claim 1, wherein the torque limiting reduces mechanical loss by 20% or more, and the statistical control is configured to realize a control response characteristic that can achieve an accuracy of ±1 second per day within a frequency range of 1 Hz to 4 Hz.

5. A method for controlling an oscillator of a mechanical timepiece, comprising: a) limiting the average impulse amount of the mainspring and escapement system to between 80% and 95% of a reference value required for the oscillator to maintain a steady amplitude; b) electronically supplying energy from a direction perpendicular to the main vibration axis while the angular velocity of the vibrator is in a zero-cross section; c) statistically controlling the energy replenishment based on a phase difference with respect to an external reference clock; A vibrator control method comprising:

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