Integrated drive and sensing device and phase detection method using a common piezoelectric element with integrated jewel bearing or balance support member for mechanical watches.

Abstract

In controlling the rate of a mechanical watch, the conventional configuration, which separately arranges a driving piezoelectric element and a phase detection sensor, has problems (increased number of parts, phase error due to spatial mismatch, high power consumption, and influence of external disturbances). This invention solves these problems and provides a device that integrates driving and detection with a single element. [Solution] A common piezoelectric element is integrated into a bearing unit that supports the balance wheel of a mechanical watch, or is positioned on a balance support member that supports the bearing unit. Both a drive circuit and a detection circuit are connected to this common piezoelectric element. The drive circuit uses the inverse piezoelectric effect to generate mechanical displacement in the common piezoelectric element and apply an external force to the oscillator. The detection circuit uses the piezoelectric effect to acquire an electrical signal corresponding to the mechanical stress transmitted from the oscillator to the common piezoelectric element. The drive signal component and the stress-induced signal component are separated by time division, bridge circuit, frequency separation, or electrode region separation.

Description

Technical Field

[0001] The present invention relates to a speed regulation mechanism for a mechanical timepiece, and more particularly to a drive-sensing integrated device and a phase detection method using the same, wherein a piezoelectric element integrated with a pallet jewel supporting a balance staff or disposed on a balance support member such as a balance cock or a main plate functions both as a drive element for an oscillator and as a sensor element for detecting mechanical stress transmitted from the oscillator, thereby realizing both driving and detection with the same piezoelectric element. As used herein, the term "pallet jewel" refers to the entire bearing unit that integrally holds a narrowly-defined pallet jewel (end stone) that supports a thrust load and a hole jewel that supports a radial load. As used herein, the term "balance support member" is a general term for members that support a balance, and includes an upper balance support plate disposed above the oscillator to support one end thereof, a lower main plate, and the like. As used herein, the term "oscillator" is a general term for an assembly that constitutes the speed regulation mechanism of a mechanical timepiece and performs reciprocating rotational motion at a constant cycle (generally called a "balance", and in established terms such as balance staff and balance cock, "balance" is used without deliberately replacing it with "oscillator"). Specifically, this "oscillator" is centered on the "balance staff", which is a shaft member serving as the center of rotation, and includes the "balance wheel", which is an inertial body fixed to the balance staff, and the "hairspring", which is an elastic body that provides restoring force to the balance staff, and the like. That is, in the present invention, the physical action exerted on the "balance staff" by the piezoelectric element provided in the pallet jewel or the piezoelectric element disposed on the balance support member is synonymous with driving the entire "oscillator". Conversely, all mechanical stress accompanying the motion of the entire "oscillator" is transmitted to the pallet jewel with the "balance staff", which is a component of the oscillator, as the aggregation point. Background Art

[0002] In recent years, technologies have been proposed to correct the rate of mechanical watches by electronic control. Patent Document 1 by the present applicant discloses an apparatus comprising at least one piezoelectric element arranged in the XY direction opposite to or orthogonal to the oscillator, a detection means for detecting the phase of the oscillator, and a control circuit that generates a pulse application probability function based on the phase difference between the output of the detection means and an external reference oscillator. In statistical control mode, the apparatus corrects the rate while setting the average external force to zero by applying symmetrical pulses to an even half-period phase window, and in stop mode, it stops the oscillator by applying brake torque through continuous or intermittent drive.

[0003] Embodiment 8 of Patent Document 1 discloses a piezoelectric element unit having a ring-shaped structure in which a piezoelectric ceramic layer is integrally sintered on the outer circumference of a bearing stone that penetrates the balance shaft. This piezoelectric element unit functions as an actuator that applies a torque pulse to an oscillator by causing displacement in the radial direction of the balance shaft.

[0004] In the configuration described in Patent Document 1, the piezoelectric element has a driving function (statistical control mode and stop mode) as its operating mode, and optical sensors, magnetic sensors, and electrostatic sensors are used as means for detecting the oscillator phase. In other words, the piezoelectric element responsible for driving and the sensor that detects the oscillator phase are configured to be separate in terms of function and physical location.

[0005] It is generally known that piezoelectric elements possess both inverse piezoelectric effect (mechanical displacement due to voltage application) and piezoelectric effect (electric charge generation due to mechanical stress). However, in the regulating mechanism of a mechanical watch, a configuration is not known in which a piezoelectric element integrated with a bearing jewel supporting the balance wheel, or a piezoelectric element placed on the balance wheel support, is used simultaneously for both driving and detection functions. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7755099 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the configuration described in Patent Document 1, the driving piezoelectric element and the phase detection sensor are separate elements, requiring multiple elements to be arranged within the movement. This presents the following problems. Firstly, because the piezoelectric element and the phase detection sensor are spatially separated, a mechanical transmission path is interposed between the drive position and the detection position. This results in a minute mechanical phase difference between the phase reference point of the balance wheel and the point of application of the drive, which imposes an upper limit on the timing control accuracy of the injection pulse. Secondly, incorporating multiple elements into the movement increases the number of parts, complicates the assembly process, and limits the miniaturization of the movement. Thirdly, when using optical sensors, power consumption is constantly generated for LED driving and light amplification. When using magnetic sensors, circuits for magnetic field generation or magnetic flux detection are required. Both of these pose power consumption constraints in battery-powered mechanical watches. Fourthly, optical sensors are affected by optical disturbances, and magnetic sensors are affected by external magnetic fields, which can lead to a decrease in detection accuracy depending on the mounting environment.

[0008] The object of the present invention is to provide a drive and sensing integrated device having the following functions in order to solve the above problems. Firstly, by using a piezoelectric element integrated with the bearing supporting the balance shaft, or positioned on the balance support member, for both driving and phase detection functions, the spatial mismatch between the driving position and the detection position is eliminated. Secondly, by realizing a self-generating sensing system that detects electrical signals generated by the mechanical stress of the oscillator itself, the power consumption of the detection system is reduced. Thirdly, the number of parts and the volume occupied within the movement are reduced. Fourthly, by providing a configuration that can be combined with the statistical control mode and stop mode disclosed in Patent Document 1, integration with existing rate control technology is achieved. [Means for solving the problem]

[0009] In a first aspect of the present invention, in a drive and sensing integrated device for a mechanical clock, a) A piezoelectric element section including at least one common piezoelectric element which is integrated with a bearing unit that supports the balance shaft of the mechanical clock, or is arranged on a balance support member that supports the bearing unit, and which functions as a driving element that imparts a mechanical action to the balance shaft, and also functions as a sensor element that detects mechanical stress transmitted from the balance shaft or oscillator, b) A drive circuit that applies a drive signal to at least one common piezoelectric element of the piezoelectric element section to impart mechanical displacement or torque pulses to the balance shaft or the oscillator by the inverse piezoelectric effect, c) A detection circuit that acquires an electrical signal corresponding to the mechanical stress generated by the piezoelectric effect from at least one common piezoelectric element of the piezoelectric element section, d) A signal separation means for separating the drive signal component corresponding to the drive signal and the stress-induced signal component corresponding to the mechanical stress, A drive and sensing integrated device is provided, characterized by having the following features. Here, the bearing unit or the balance support member supporting the bearing unit is not merely a support member, but an observation point where mechanical information from the balance shaft is aggregated. The balance wheel is the point where mechanical influences from the balance wheel, hairspring, and escapement converge. Mechanical stresses corresponding to the oscillator's phase, amplitude, damping, disturbances, and drive response are transmitted to the bearing unit or balance support member that supports the balance wheel.

[0010] The aforementioned shared piezoelectric element may have a structure in which a ring-shaped piezoelectric ceramic layer is integrally sintered around the outer circumference of a bearing stone body made of single-crystal corundum, and may generate radial displacement of the balance axis and output an electrical signal corresponding to the radial stress from the balance axis.

[0011] The piezoelectric element section may include at least one of the following: a plurality of common piezoelectric elements arranged radially opposite each other across the balance shaft; a plurality of common piezoelectric elements arranged on both shoulders of the balance shaft; a plurality of common piezoelectric elements arranged in mutually orthogonal XY directions with respect to the balance shaft; a common piezoelectric element arranged in a cross-axis coupling configuration with respect to the balance shaft; or a common piezoelectric element arranged at an angle via an inclined block opposite to the balance shaft.

[0012] The signal separation means is a) Switching means for selectively connecting the drive circuit and the detection circuit to the electrodes of the shared piezoelectric element in a time-division manner, b) Differential separation means for extracting the stress-induced signal component by removing the drive signal component in phase using a bridge circuit connected to the common piezoelectric element, c) Frequency separation means that arranges the drive signal component and the stress-induced signal component in different frequency bands and separates them using a filter circuit or a synchronous detection circuit. d) An electrode separation means that divides the electrodes of the shared piezoelectric element into a plurality of electrode regions, connects the drive circuit to the first electrode region, and connects the detection circuit to the second electrode region. It may also be stated that it includes at least one of the following.

[0013] The detection circuit may include a voltage follower using an FET input type operational amplifier, and acquire the stress-induced signal component as the open-circuit voltage of the shared piezoelectric element.

[0014] The detection circuit may include a charge amplifier circuit that sets the inverting input of the operational amplifier to virtual ground and converts the charge flowing in from the common piezoelectric element via a feedback capacitance into a voltage.

[0015] The system may also include an analysis circuit that, based on the output of the detection circuit, acquires a time-resolved mechanical stress profile within each vibration of the oscillator, and extracts at least one of the following from the mechanical stress profile: zero-crossing of the amplitude, amplitude peak, vibration amplitude, phase, or vibration amplitude attenuation rate.

[0016] A control circuit that controls the drive circuit may be provided, wherein the control circuit calculates the mechanical response of the vibrator to the drive signal based on the mechanical stress profile acquired via the detection circuit during or immediately after application of the drive signal, and determines or corrects at least one of the application timing, application amplitude, application polarity, pulse width, or application probability of the drive signal to be applied next in accordance with the mechanical response.

[0017] In a second aspect of the present invention, there is provided a vibrator phase detection method for a mechanical timepiece, comprising: a) applying a drive signal to at least one common piezoelectric element integrated in a bearing unit that supports a balance shaft of the mechanical timepiece or disposed on a balance support member that supports the bearing unit, to generate mechanical displacement or a torque pulse; b) acquiring, from the common piezoelectric element, an electrical signal corresponding to mechanical stress transmitted from the vibrator of the mechanical timepiece; c) separating a drive signal component corresponding to the drive signal and a stress-induced signal component corresponding to the mechanical stress; d) extracting phase information of the vibrator from the stress-induced signal component; A vibrator phase detection method characterized by comprising the above steps is provided.

[0018] In this method, closed-loop control may be performed in which a mechanical response of the vibrator is acquired from the stress-induced signal component acquired during or immediately after application of the drive signal, and at least one of application timing, application amplitude, application polarity, pulse width, or application probability of a next drive signal to be applied is determined or corrected based on the mechanical response. That is, driving, stress detection, phase extraction, and drive response feedback are performed at the same mechanical point by the common piezoelectric element integrated in the bearing unit or disposed at the balance shaft support portion, which is the balance support member. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1]Figure 1 is an overall configuration diagram of a mechanical clock 1000 employing the drive and sensing integrated device of this embodiment. [Figure 2] Figure 2 is a block diagram showing the configuration of the drive and sensing integrated device of Embodiment 1, which is configured as a system. [Figure 3] Figure 3 is an illustrative diagram of a shared piezoelectric element with an integrated support stone, in which a ring-shaped piezoelectric ceramic layer is integrally sintered around the outer circumference of the support stone body. [Figure 4] Figure 4 is a cross-sectional view showing the configuration of a common piezoelectric element with an integrated support stone. [Figure 5] Figure 5 is an illustrative diagram of the structure of a common piezoelectric element with integrated bearings in a two-shoulder arrangement of the balance axis, an XY arrangement that is orthogonal to each other, and a cross-axis coupling arrangement. [Figure 6] Figure 6 is an illustrative diagram of the structure of a common piezoelectric element arranged on the same balance support member as a ring-shaped bearing stone, which has the same shape as the bearing stone in this embodiment but does not include a common piezoelectric element. [Figure 7] Figure 7 is an overall configuration diagram of a mechanical clock employing the drive and sensing integrated device of this embodiment. [Figure 8] Figure 8 is a block diagram showing the configuration of the drive and sensing integrated device of Embodiment 2, which is configured as a system. [Figure 9] Figure 9 is an overall configuration diagram of a mechanical clock employing the drive and sensing integrated device of this embodiment. [Figure 10] Figure 10 is a block diagram showing the configuration of the drive and sensing integrated device of Embodiment 3, which is configured as a system. [Figure 11] Figure 11 is an overall configuration diagram of a mechanical clock employing the drive and sensing integrated device of this embodiment. [Figure 12] Figure 12 shows a plan view and a cross-sectional view of the stone-integrated common piezoelectric element of Example 4. [Modes for carrying out the invention]

[0020] The drive and sensing integrated device of this embodiment adopts as its basic structure an arrangement of piezoelectric elements that exerts a physical effect on the balance shaft support (for example, a balance shaft through-type structure) among the various piezoelectric element arrangements disclosed in the embodiment of Patent Document 1, and connects both a drive circuit and a detection circuit to the piezoelectric element, thereby realizing both drive and detection functions with a single piezoelectric element (a piezoelectric element that realizes both functions in this way is called a shared piezoelectric element). Any of the following methods may be used to achieve both drive and detection: a time-division method, a frequency-separation method, a spatial-separation method, a bridge method, etc. Embodiments of the present invention will be described below with reference to the drawings.

[0021] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Examples]

[0022] Figure 1 is an overall configuration diagram of a mechanical clock 1000 employing the drive and sensing integrated device of this embodiment. The mechanical watch's oscillator mechanism consists of a balance wheel 1001, a balance shaft 1002 that runs through the center of the entire balance wheel, a shared piezoelectric element 1003 with an integrated jewel bearing that supports the balance shaft and constitutes the drive and sensing integrated device, an integrated control circuit 1004 that constitutes the drive and sensing integrated device, a communication unit 1005, an external reference oscillator 1006, a power supply block 1007, a balance wheel support plate 1008, and a base plate 1009. Here, the drive and sensing integrated device is a system consisting of hardware-separated components: a shared piezoelectric element 1003 with an integrated bearing stone and an integrated control circuit 1004.

[0023] The communication unit 1005 consists of a BLE module and performs functions such as receiving automatic rate correction commands based on external time signals, receiving remote stop commands from external sources, firmware updates, and log transmission. The external reference oscillator 1006 oscillates at a reference frequency and emits a reference oscillation signal, independently of the oscillator mechanism of the clock to be installed. The power supply block 1007 consists of a button battery (1.55V), a DC-DC boost converter that increases the voltage of the button battery to 10V, and a current monitor that monitors the average current I_avg.

[0024] The balance plate 1008 is positioned above the balance (shown in an inverted state in Figure 1) and is a member for supporting one end of the balance shaft. The base plate 1009 is a member that constitutes the support structure of the watch mechanism and is a member that directly or indirectly supports the balance itself or the balance bridge or other mechanism members.

[0025] Figure 2 is a block diagram showing the configuration of the drive and sensing integrated device of Embodiment 1, which is configured as a system. The drive and sensing integrated device of this embodiment is composed of a shared piezoelectric element 1003 with an integrated receiver, an analog SPDT switch 2001, a drive circuit 2002, a detection circuit 2003, and an integrated control circuit 1004 which consists of a control circuit 2004.

[0026] (Time-division switching method) This device comprises a shared piezoelectric element consisting of a piezoelectric ceramic layer integrally sintered on a bearing stone supporting the balance shaft, an analog SPDT switch 2001 connected to the shared piezoelectric element, a drive circuit 2002 and a detection circuit 2003 connected via the analog SPDT switch, and a control circuit 2004 that manages these components.

[0027] Here, the connection lines indicated by A and A' represent connections made by time division (choosing either A or A') using an analog SPDT switch. In the block diagram of Figure 2, the connection between the shared piezoelectric element and the analog SPDT switch is indicated by an arrow. This represents a functional connection where the application of the drive signal and the acquisition of the stress-induced signal occur bidirectionally via different paths. Physically, they are electrically connected in parallel by two wires in each direction.

[0028] The shared piezoelectric element constituting the integrated support stone shared piezoelectric element 1003 has a structure similar to Example 8 of Patent Document 1, in which a ring-shaped piezoelectric ceramic layer is integrally sintered around the outer circumference of a support stone body made of single-crystal corundum. Electrodes are formed on the upper and lower surfaces of the piezoelectric ceramic layer, and these electrodes are selectively connected to a drive circuit or a detection circuit via an analog SPDT switch 2001.

[0029] Figure 3 is an image diagram of a shared piezoelectric element with an integrated support stone, in which a ring-shaped piezoelectric ceramic layer is integrally sintered around the outer circumference of the support stone body. Similar to Example 8 in Patent Document 1, it is made of single-crystal corundum. The integrated support stone common piezoelectric element 1003 is composed of two integrated support stone common piezoelectric elements 3001 and 3002. The jewel bearing body 3003 is formed from single-crystal corundum, and a ring-shaped piezoelectric ceramic layer 3004 with a thickness of 0.11 mm is integrally sintered onto its outer ring portion. Electrodes are formed on the upper and lower surfaces so that the ring can be driven in the Z-axis thickness mode. Two jewel bearing integrated shared piezoelectric elements 3001 and 3002 are arranged radially (diameterally) opposite each other surrounding the balance shaft 1002, and the control circuit 2004 excites them in opposite phases, thereby applying torque to the balance as ± Z-axis expansion and contraction of the ring as ± radial (diameterally) displacement at the center of the hole. The external forces and moments generated by the two elements are always canceled out, preventing vibration of the mechanical watch case and base plate.

[0030] Figure 4 is a cross-sectional view showing the configuration of a common piezoelectric element with an integrated support stone. 4002 is a cross-sectional view obtained by cutting along the cutting line BB' indicated in the plan view 4001 of the integrated support stone common piezoelectric element. The two integrated receiver-type shared piezoelectric elements 3001 and 3002 consist of a single-crystal corundum layer 3003 of the receiver body, a ring-shaped piezoelectric ceramic layer 3004, and electrodes 4003 that cover the upper and lower surfaces of the ring-shaped piezoelectric ceramic layer.

[0031] The arrangement configuration of the shared piezoelectric element with integrated bearing stone in the present invention is not limited to the arrangement configuration of the balance shaft through-type structure in this embodiment. Among the various arrangements disclosed in Patent Document 1, the drive and sensing integrated configuration of the present invention can be very suitably applied to arrangement configurations that exert a physical effect on the balance shaft or members near the balance shaft, such as a balance staff shoulder arrangement (arrangement on both shoulders of the balance shaft), an XY direction arrangement with the balance shaft as the center orthogonal to each other, a cross-axis coupling arrangement with respect to the balance shaft, or an inclined arrangement by installing on an inclined surface formed by installing via an inclined block arranged opposite to the balance shaft.

[0032] The detection circuit 2003 includes a voltage follower circuit using an FET input type operational amplifier and acquires a stress-induced signal as the open-circuit voltage of a common piezoelectric element with an integrated support transistor. A discharge resistor is connected in parallel with the aforementioned integrated piezoelectric element to the non-inverting input terminal of the FET-input type operational amplifier, in order to prevent output saturation due to the input bias current. Here, the cutoff frequency of the high-pass filter formed by the self-capacitance of the integrated piezoelectric element and the discharge resistance is set to a high resistance value of several hundred MΩ to several GΩ so that it is sufficiently lower than the oscillation frequency of the balance wheel (e.g., a few Hz band). This configuration allows for high-precision acquisition of stress-induced signals without attenuating the low-frequency open-circuit voltage associated with mechanical stress fluctuations.

[0033] In another embodiment, the detection circuit 2003 may be configured to include a charge amplifier circuit that uses the inverting input of a FET-input operational amplifier as virtual ground and converts the charge flowing in from the shared piezoelectric element via a feedback capacitor into a voltage. Specifically, the charge amplifier circuit comprises a FET-input operational amplifier and a feedback capacitor and a feedback resistor connected in parallel between the inverting input terminal and the output terminal of the operational amplifier. The advantage of employing a charge amplifier circuit is that the inverting input terminal of the operational amplifier functions as an imaginary short (virtual ground), so fluctuations in the capacitance of the integrated piezoelectric element itself and parasitic capacitance occurring in the wiring path do not affect the output gain. This makes it possible to extract stable stress-induced signals even with environmental changes and variations in implementation. Here, the feedback resistor functions as a discharge path to prevent output saturation (drift phenomenon) caused by the continuous accumulation of the op-amp's input bias current in the feedback capacitance, and to stabilize the DC operating point. Furthermore, the time constant determined by the feedback capacitance and feedback resistor forms a high-pass filter in the detection circuit. In order to detect low-frequency mechanical stress associated with the balance wheel's oscillation frequency (e.g., a few Hz band) without attenuation, the circuit constants are designed so that the cutoff frequency of the high-pass filter is sufficiently lower than the balance wheel's oscillation frequency. Specifically, when the feedback capacitance is set to a value of several tens to several hundred pF, the feedback resistor is set to a high resistance value of several hundred MΩ to several tens of GΩ.

[0034] During the drive period, the control circuit 2004 switches the analog SPDT switch to the drive circuit side and applies a drive signal to the shared piezoelectric element to generate mechanical displacement. After the drive period ends, the analog SPDT switch is switched to the detection circuit side and an electrical signal generated by the mechanical stress transmitted from the balance shaft to the shared piezoelectric element is acquired. Since the drive period is on the order of a few microseconds to a few milliseconds relative to the balance period T (typically 250 to 400 milliseconds), most of the time outside the drive period can be used as the detection period.

[0035] (Closed-loop control mode) The drive-sensing integrated device of this embodiment performs a closed-loop control mode in which the mechanical response of the oscillator is evaluated based on the detection signal immediately after the application of the drive signal, and the feedback is given to the control system. Specifically, the detection signal from the detection circuit is first subjected to band-pass filtering in a bandwidth that includes the fundamental frequency of the temperature oscillator or its harmonics. At this time, abnormal waveforms that exceed a predetermined threshold due to external disturbances are excluded. Then, the stress waveform over multiple periods from which the noise has been removed is correlated with a reference waveform, and the time of maximum correlation, the zero-crossing time, or the instantaneous phase estimated by a PLL (Phase-Locked Loop) is determined and calculated with high accuracy as the current "oscillator phase". The control circuit 2004 compares and monitors the calculated oscillator phase transition and amplitude fluctuations with a reference state to identify and acquire in real time the "mechanical response (amplitude change, phase shift, damping characteristics)" that the previous drive signal imparted to the oscillator mechanism. Then, based on the acquired mechanical response, it optimally determines and corrects the application timing, applied amplitude, and applied polarity of the next applied drive signal.

[0036] In this closed-loop control mode, an applied probability P(t) is generated from the phase difference Δφ between the temp 1001 and the external reference oscillator 1006. A dynamic correction term corresponding to the mechanical response can be added to the probability function P(t) used in the statistical control mode operation (described in Patent Document 1), which maintains the average external force at zero by applying + / - pulses in an even half-period phase window with a 0° / 180° phase window. This allows for the real-time detection of disturbances such as temperature changes, posture changes, and barrel torque fluctuations as mechanical responses, improving the ability to track these disturbances.

[0037] (Estimated detection sensitivity) The balance wheel weight is assumed to be 0.5g, the amplitude ±270 degrees, and the balance wheel period 250 milliseconds. The radial stress from the balance wheel axis to the balance bridge typically varies over time in the range of several millinewtons to tens of millinewtons, due to the combination of the balance wheel's own weight and its dynamic components.

[0038] The sensitivity of the integrated piezoelectric element with a bearing stone is approximately in the range of 0.1 to 0.5 volts per Newton, based on its shape and material constants (piezoelectric constant d31 = 200 × 10⁻¹² C / N, ring outer diameter 2.0 mm, inner diameter 1.0 mm, thickness 0.11 mm). This means that it generates a voltage output of several hundred microvolts to several millivolts in response to stress fluctuations of several millinewtons transmitted from the oscillator.

[0039] When using the 12-bit ADC built into the MCU, the main vibration components of the oscillator can be sufficiently detected. If even higher resolution is required, an external 24-bit ΔΣ ADC can be used to acquire the mechanical stress profile within each vibration at sub-microvolt resolution.

[0040] (Modified structure of a shared piezoelectric element with integrated support stone) The structure of the integrated piezoelectric element with bearing is not limited to the balance shaft through-type structure adopted here. Among the various arrangements disclosed in Patent Document 1, the drive-sensing integrated configuration of the present invention can be very suitably applied to arrangements that exert a physical effect on the balance shaft or members near the shaft, such as a balance shaft shoulder arrangement, an XY direction arrangement that is orthogonal to each other, a cross-axis coupling arrangement, or an inclined arrangement via an inclined block. Figure 5 is an illustrative diagram of the structure of a common piezoelectric element with integrated bearings, arranged in two shoulder configurations around the balance axis, in mutually orthogonal XY directions around the balance axis, and in a cross-axis coupling configuration relative to the balance axis. 5000A shows a balance shaft and a balance shaft with a shared piezoelectric element integrated with a bearing jewel, employing a structure where the bearing jewel is positioned on both shoulders of the balance shaft. The bearing jewel 5003 has the shared piezoelectric element 5002 positioned on both shoulders of the balance shaft 5001, and the arrow 5004 indicates the direction of the driving and sensing stress. Therefore, the surface through which the arrow passes is the electrode surface. 5000B shows a balance axis and a shared piezoelectric element with an integrated bearing, employing a structure with mutually orthogonal XY directional arrangement. The bearing 5007 has the shared piezoelectric element 5006 positioned in mutually orthogonal XY directions 5005 with the balance axis 5001 as the center, and the arrow 5008 indicates the direction of the driving and sensing stress. Therefore, the surface through which the arrow passes becomes the electrode surface. 5000C shows a balance shaft and a balance shaft with an integrated common piezoelectric element that employs a cross-axis coupling arrangement structure for the balance shaft. The balance shaft 5001 has a common piezoelectric element 5009 positioned in a cross-axis coupling arrangement, and the arrow 5011 indicates the direction of the driving and sensing stress. Therefore, the surface through which the arrow passes is the electrode surface.

[0041] (Modified structure of a common piezoelectric element with a temperature support member arrangement) The arrangement of the shared piezoelectric elements in the present invention is not limited to the integrated support stone arrangement adopted herein. Figure 6 is an illustrative diagram of a common piezoelectric element placed on a balance plate that supports a ring-shaped bearing stone, which has the same shape as the bearing stone in this embodiment but does not include a common piezoelectric element. The mechanical watch's oscillator mechanism consists of a balance wheel 1001, a balance shaft 1002 that runs through the center of the entire balance wheel, a ring-shaped jewel bearing 6001 that does not include a shared piezoelectric element and supports the balance shaft, a shared piezoelectric element 6002, and a balance wheel bearing plate 1008. Here, the shared piezoelectric element 6002 is positioned on the balance plate 1008 and exerts a mechanical action on the balance shaft, as well as receiving mechanical stress transmitted from the balance shaft or the oscillator of a mechanical watch. Here, the shared piezoelectric elements are positioned on the balance plate so as to be located on both shoulders of the balance stone, but the arrangement of the shared piezoelectric elements relative to the balance stone is not limited to this. Arrangements in the XY directions that are mutually orthogonal to each other with the balance stone as the center, arrangements of cross-axis couplings facing the balance stone, and even inclined arrangements via inclined blocks by arranging inclined blocks in the above-mentioned positional relationship and installing them on the inclined surface can be adopted as appropriate. [Examples]

[0042] (Simultaneous parallel operation using a bridge circuit) In this embodiment, a common piezoelectric element is incorporated into a Wheatstone bridge type circuit, employing a configuration that differentially separates the drive signal and the stress-induced signal. The drive signal is removed as an in-phase component, and only the mechanical stress-induced signal appears in the detection circuit as a differential component. This allows drive and detection to be performed simultaneously and in parallel without temporal separation. Furthermore, modified structures of the shared piezoelectric element with integrated support stone shown in Example 1, and modified structures of the shared piezoelectric element with temperature support member arrangement, can be used as the shared piezoelectric elements in this embodiment.

[0043] Figure 7 is an overall configuration diagram of the mechanical clock 7000 employing the drive and sensing integrated device of this embodiment. The mechanical watch's oscillator mechanism consists of a balance wheel 7001, a balance shaft 7002 that runs through the center of the entire balance wheel, a jewel-integrated common piezoelectric element 7003 that constitutes the drive and sensing integrated device, an integrated control circuit 7004 that constitutes the drive and sensing integrated device, a communication unit 7005, an external reference oscillator 7006, and a power supply block 7007. Here, the drive and sensing integrated device is a system consisting of two hardware-separated elements: a shared piezoelectric element 7003 with an integrated bearing plate and an integrated control circuit 7004.

[0044] The following describes an integrated control circuit 7004 that differs from that of Example 1, and the description of a configuration similar to that of Example 1 will be omitted.

[0045] Figure 8 is a block diagram showing the configuration of the drive and sensing integrated device of Embodiment 2, which is configured as a system. The drive and sensing integrated device of this embodiment is configured with a shared piezoelectric element 7003 with an integrated Wheatstone bridge type circuit 8001, a drive circuit 8002, a detection circuit 8003, and an integrated control circuit 7004 which consists of a control circuit 8004.

[0046] Here, the connection line indicated by C represents a simultaneous parallel connection using the Wheatstone bridge type circuit 8001. In the block diagram of Figure 8, the connection between the shared piezoelectric element and the bridge circuit is indicated by bidirectional arrows. This represents a functional connection where the application of the drive signal and the acquisition of the stress-induced signal are performed bidirectionally through the same path. Physically, they are electrically connected in parallel by, for example, two wires.

[0047] The Wheatstone bridge circuit 8001 is combined with a reference capacitance corresponding to the capacitance of the shared piezoelectric element, and the differential amplifier differentiates the fluctuations on the shared piezoelectric element side and the fluctuations on the reference capacitance side when a drive signal is applied. If the charge of the shared piezoelectric element fluctuates due to mechanical stress, the bridge balance is disrupted, and a stress-induced signal appears in the differential output. In other words, the Wheatstone bridge type circuit 8001 in this embodiment is configured as an AC impedance bridge circuit in which the capacitance (self-capacitance) of the integrated common piezoelectric element is incorporated as one side (first arm) of the bridge. Specifically, the Wheatstone bridge type circuit 8001 comprises the aforementioned integrated common piezoelectric element, a reference capacitance element (second arm) having a capacitance equivalent to the self-capacitance of the common piezoelectric element, and a pair of bridge lower impedance elements (third and fourth arms). The pair of bridge lower impedance elements may be a pair of resistive elements or a pair of capacitive elements, each having equivalent resistance values.

[0048] In the connection structure of the Wheatstone bridge type circuit 8001, a drive signal from the drive circuit is constantly applied to the common input node where one end of the shared piezoelectric element and one end of the reference capacitance element are connected to each other. The connection point between the other end of the shared piezoelectric element and the third arm forms a first output node (midpoint A), and the connection point between the other end of the reference capacitance element and the fourth arm forms a second output node (midpoint B). These first and second output nodes are electrically connected to the inverting input terminal and non-inverting input terminal of the differential amplifier of the detection circuit located downstream, respectively.

[0049] In this configuration, when a drive signal (for example, a pulse signal of several tens to several hundreds of Hz, or a signal with a superimposed carrier frequency of several kHz) is applied from the drive circuit to the common input node, the bridge circuit is adjusted to a balanced state (i.e., the ratio of the impedance of the common piezoelectric element to the impedance of the third arm is equal to the ratio of the impedance of the reference capacitance element to the impedance of the fourth arm), so that common-phase drive signal components appear at the first and second output nodes. Consequently, these common-phase components cancel each other out (common-phase rejection) in the subsequent differential amplifier, and no drive signal components appear at the output of the differential amplifier.

[0050] On the other hand, when mechanical stress is applied from the balance shaft to the integrated common piezoelectric element, the piezoelectric effect causes a charge fluctuation (stress-induced electromotive force) only in that common piezoelectric element. Since this charge fluctuation does not occur on the reference capacitance element side, the balance of the bridge is disrupted, and only the potential of the first output node changes dynamically. As a result, the potential difference (differential component) generated between the first output node and the second output node is amplified and extracted by the differential amplifier as a purely stress-induced signal. This makes it possible to acquire a stress-induced signal in real time and with high sensitivity from the same common piezoelectric element without temporal switching, while continuing the driving operation by the drive circuit.

[0051] The control circuit 8004 applies a drive signal to the integrated piezoelectric element via the Wheatstone bridge circuit 8001, generating mechanical displacement. At this time, the drive signal component is canceled out by the balancing action of the Wheatstone bridge circuit 8001, so the detection circuit 8003 acquires the electrical signal generated by the mechanical stress transmitted from the balance shaft to the shared piezoelectric element simultaneously and in parallel, without being affected by the applied state of the drive signal. As a result, there is no need to temporally separate the drive period and the detection period by a switch, and it can be used as a continuous detection period, including the period during which the drive signal is applied, over the entire balance period T (typically 250 milliseconds to 400 milliseconds).

[0052] (Closed-loop control mode) The drive and sensing integrated device of this embodiment acquires the mechanical response (amplitude change, phase shift, damping characteristics) that the drive signal imparts to the oscillator mechanism in real time from the detection signal during and immediately after the application of the drive signal, using the simultaneous parallel detection function of the Wheatstone bridge type circuit 8001. The control circuit 8004 executes a closed-loop control mode that feeds back the mechanical response to determine the timing, amplitude, and polarity of the next drive signal application.

[0053] In this closed-loop control mode, an applied probability P(t) is generated from the phase difference Δφ between the temp 7001 and the external reference oscillator 7006. A dynamic correction term corresponding to the mechanical response can be added to the probability function P(t) used in the statistical control mode operation (described in Patent Document 1), which maintains the average external force at zero by applying + / - pulses in an even half-period phase window with a 0° / 180° phase window. In this configuration, the mechanical response can be captured simultaneously with the application of the drive pulse without interruption, allowing for real-time detection of disturbances such as temperature changes, posture changes, and barrel torque fluctuations as mechanical responses, thereby improving the ability to track these disturbances. [Examples]

[0054] (Frequency separation method) In this embodiment, the drive signal and the detection signal are placed in different frequency bands. The drive signal is, for example, a pulse signal ranging from tens to hundreds of Hz, and the signal caused by mechanical stress mainly consists of low-frequency components corresponding to the balance wheel's oscillation period (several Hz). When the frequency bands of the two signals overlap, a carrier frequency (e.g., several kHz) is superimposed on the drive signal, and the stress-induced signal is separated by synchronous detection on the detection circuit side. This allows for simultaneous execution of drive and detection without time-division switching. Furthermore, modified structures of the shared piezoelectric element with integrated support stone shown in Example 1, and modified structures of the shared piezoelectric element with temperature support member arrangement, can be used as the shared piezoelectric elements in this embodiment.

[0055] Figure 9 is an overall configuration diagram of the mechanical clock 9000 employing the drive and sensing integrated device of this embodiment. The mechanical watch's oscillator mechanism consists of a balance wheel 9001, a balance shaft 9002 that runs through the center of the entire balance wheel, a jewel-integrated common piezoelectric element 9003 that supports the balance shaft and constitutes the drive and sensing integrated device, an integrated control circuit 9004 that constitutes the drive and sensing integrated device, a communication unit 9005, an external reference oscillator 9006, and a power supply block 9007. Here, the drive and sensing integrated device is a system consisting of hardware-separated components: a shared piezoelectric element 9003 with an integrated bearing stone and an integrated control circuit 9004.

[0056] The following describes an integrated control circuit 9004 that differs from that of Example 1, and the description of a configuration similar to that of Example 1 will be omitted.

[0057] Figure 10 is a block diagram showing the configuration of the drive and sensing integrated device of Embodiment 3, which is configured as a system. The drive and sensing integrated device of this embodiment is configured with a shared piezoelectric element 9003 with an integrated drive circuit 10001, a detection circuit 10002, and an integrated control circuit 9004 which consists of the control circuit 10003.

[0058] The drive circuit 10001 includes a pulse-based signal generation unit that generates drive pulses (tens of Hz to hundreds of Hz) for driving the balance wheel, a local oscillator that outputs a sine wave or square wave of the carrier frequency (several kHz), and a modulator (multiplier) that applies amplitude modulation by multiplying the drive pulses by the carrier frequency. This configuration allows the drive signal to be shifted (modulated) to a high-frequency band and applied to the integrated piezoelectric element 9003 either continuously or selectively.

[0059] The detection circuit 10002 includes an input buffer (voltage follower, etc.) that receives a mixed signal of the drive component and stress component from the integrated common piezoelectric element 9003, a synchronous detector (multiplier) that multiplies the carrier frequency (reference signal) branched from the local oscillator of the drive circuit 10001 with the mixed signal, and a low-pass filter that blocks high-frequency carrier components and their harmonic components from the output of the synchronous detector. As a result, only the low-frequency stress-induced signal (baseband signal) corresponding to the oscillation period of the balance wheel (several Hz) is electrically separated from the drive signal component and extracted with high precision from the mixed signal.

[0060] The control circuit 10003 digitally controls the timing and amplitude of the drive pulses in the drive circuit 10001 based on a reference clock from the external reference oscillator 9006. Simultaneously, the control circuit 10003 acquires the analog low-frequency stress-induced signal output from the low-pass filter of the detection circuit 10002 as digital data via its built-in A / D converter (ADC). The control circuit 10003 extracts the zero-crossing and phase information of the temp 9001's amplitude from this acquired signal waveform through calculation, and performs calculation processing for closed-loop control (or statistical control) to dynamically determine the parameters of the drive pulse to be modulated and applied next, based on the phase difference with the external reference oscillator 9006. [Examples]

[0061] (Spatial separation method using multiple electrodes) In this embodiment, the piezoelectric ceramic layer electrode is divided into multiple regions, and the drive electrode and the detection electrode are assigned to separate regions. When a drive signal is applied to the drive electrode, mechanical displacement occurs throughout the shared piezoelectric element, and in the detection electrode region, a charge is generated corresponding to this mechanical displacement and the mechanical stress transmitted from the oscillator. By electrically insulating the detection electrode from the drive electrode, direct leakage of the drive signal can be suppressed. Furthermore, modified structures of the shared piezoelectric element with integrated support stone shown in Example 1, and modified structures of the shared piezoelectric element with temperature support member arrangement, can be used as the shared piezoelectric elements in this embodiment.

[0062] Figure 11 is an overall configuration diagram of the mechanical clock 11000 employing the drive and sensing integrated device of this embodiment. The mechanical watch's oscillator mechanism consists of a balance wheel 11001, a balance shaft 11002 that runs through the center of the entire balance wheel, a jewel-integrated common piezoelectric element 11003 that supports the balance shaft and constitutes the drive and sensing integrated device, an integrated control circuit 11004 that constitutes the drive and sensing integrated device, a communication unit 11005, an external reference oscillator 11006, and a power supply block 11007. Here, the drive and sensing integrated device is a system consisting of hardware-separated components: a shared piezoelectric element 11003 with an integrated bearing stone and an integrated control circuit 11004.

[0063] The following description will focus on a different integrated piezoelectric element 11003 and integrated control circuit 11004 from those in Example 1, and will omit the description of the configuration similar to that in Example 1.

[0064] The electrodes formed on the entire upper and lower surfaces of the "ring-shaped (annular)" piezoelectric ceramic layer provided on the outer circumference of the receiving stone body shown in Example 1 have a "ring-shaped (annular or ring-shaped)" shape, and the ring-shaped electrode on the upper surface and the ring-shaped electrode on the lower surface form a pair of electrode structures that face each other with the piezoelectric ceramic layer sandwiched in the thickness direction. In this embodiment, the electrodes are divided into multiple sectors by making slits (insulating thin wires) along the circumferential direction of this ring shape.

[0065] Figure 12 shows a plan view and a cross-sectional view of the stone-integrated common piezoelectric element of Example 4. 12000A is a plan view of a common piezoelectric element with an integrated support stone, and 12000B is a cross-sectional view taken by cutting along the cutting line FF' indicated on the plan view. Similar to Example 1, the receiving stone body 12001 is formed from single-crystal corundum, and a ring-shaped piezoelectric ceramic layer 12002 with a thickness of 50 to 80 micrometers is integrally sintered onto its outer ring portion. Electrodes 12003 are formed on the upper and lower surfaces, and slits 12004 are made along the circumferential direction of the ring shape, allowing the parts of the structure, which are divided into multiple sectors, to be separated and driven or detected in the Z-axis thickness mode.

[0066] In this embodiment, at least one of the electrodes formed on the upper and lower surfaces of the piezoelectric ceramic layer is physically and electrically divided into multiple regions via a slit, and these regions are assigned separately as a driving electrode (first electrode region) and a detection electrode (second electrode region). As for the specific electrode pattern shape, a plurality of fan-shaped electrode patterns divided along the circumferential direction of the piezoelectric ceramic layer are employed, but the electrode pattern by division according to the present invention is not limited to this. For example, an inner and outer double ring-shaped (annular band-shaped) electrode pattern divided concentrically along the radial direction of the piezoelectric ceramic layer can be employed. Alternatively, by dividing the upper electrode in the circumferential direction to form a pair of semi-circular drive electrodes and a pair of semi-circular detection electrodes electrically insulated from these, and using a common full-ring electrode (ground electrode) on the lower electrode, it is possible to effectively suppress direct leakage of the drive signal while maintaining a simple structure, and to spatially separate the drive and detection within the same element.

[0067] According to the present invention, the following effects are achieved. Firstly, by achieving both driving and detection with a single shared piezoelectric element, the need to place a separate phase detection sensor within the movement is eliminated, reducing the number of parts and the volume occupied by the movement. Secondly, because the drive position and the detection position perfectly coincide, phase errors caused by the mechanical transmission path between them are eliminated in principle. This improves the accuracy of the phase window in the statistical control mode described in Patent Document 1. Thirdly, because the detection system utilizes the piezoelectric effect, which generates electricity through the mechanical stress of the oscillator, it does not require an external light source, magnetic field source, or excitation voltage source, thus reducing power consumption. Fourthly, unlike optical sensors, it is not affected by optical disturbances, and unlike magnetic sensors, it is not affected by external magnetic fields, thus suppressing a decrease in detection accuracy due to the wearing environment. Fifth, since it is possible to obtain the mechanical response immediately after the application of the drive signal, it is possible to extend the statistical control mode disclosed in Patent Document 1 to a closed-loop control mode in which drive, stress detection, phase extraction, and mechanical response feedback are added at the same mechanical point by using a common piezoelectric element arranged in the balance shaft support part, such as a bearing unit or balance support member. Sixth, the present invention is applicable to all of the various shared piezoelectric element arrangements disclosed in Patent Document 1, and a wide variety of configurations can be developed by combining it with Patent Document 1. [Industrial applicability]

[0068] The drive and sensing integrated device of the present invention is applicable to all mechanical timekeeping devices that require long-term rate stability and miniaturization, such as high-end mechanical watches, marine chronometers for ships, and mechanical clocks. In particular, by combining it with the statistical drive control and electronic hack integrated device for mechanical watches described in Patent Document 1, it integrates high-precision rate correction and oscillator phase detection with the minimum number of parts. This will enable the creation of next-generation mechanical watches. [Explanation of symbols]

[0069] 1001 Balance wheel constituting the oscillator mechanism 1002 Balance Axis 1003 Integrated Piezoelectric Element 1004 Integrated control circuit 1005 Communications Department 1006 External Reference Oscillator 1007 Power Block 1008 Balance plate 1009 Main plate 8001 Wheatstone bridge circuit 8002 Drive Circuit 8003 Detection Circuit 8004 Control Circuit 12001 Receiving stone body 12002 Ring-shaped piezoelectric ceramic layer 12003 Electrode 12004 Slit

Claims

1. In a drive and sensing integrated device for a mechanical watch, a) A piezoelectric element section including at least one common piezoelectric element which is integrated with a bearing unit that supports the balance shaft of the mechanical clock, or is arranged on a balance support member that supports the bearing unit, and functions as a driving element that imparts a mechanical action to the balance shaft, and also functions as a sensor element that detects mechanical stress transmitted from the balance shaft or oscillator, b) A drive circuit that applies a drive signal to at least one common piezoelectric element of the piezoelectric element section to impart mechanical displacement or torque pulses to the balance shaft or the oscillator by the inverse piezoelectric effect, c) A detection circuit that acquires an electrical signal corresponding to the mechanical stress generated by the piezoelectric effect from at least one common piezoelectric element of the piezoelectric element section, d) A signal separation means for separating the drive signal component corresponding to the drive signal and the stress-induced signal component corresponding to the mechanical stress, A drive and sensing integrated device characterized by comprising the following features.

2. The drive and sensing integrated device according to claim 1, wherein the common piezoelectric element has a structure in which a ring-shaped piezoelectric ceramic layer is integrally sintered on the outer circumference of a support stone body made of single crystal corundum, and generates radial displacement of the balance axis and outputs an electrical signal corresponding to the radial stress from the balance axis.

3. The drive and sensing integrated device according to claim 1, wherein the arrangement of the piezoelectric elements in the piezoelectric element section, including the shared piezoelectric element, is at least one arrangement selected from the following: arrangement facing each other radially across the balance shaft, arrangement on both shoulders of the balance shaft, arrangement in mutually orthogonal XY directions around the balance shaft, cross-axis coupling arrangement with respect to the balance shaft, or inclined arrangement with respect to the balance shaft via an inclined block facing the balance shaft.

4. In the apparatus according to any one of claims 1 to 3, the signal separation means is a) Switching means for selectively connecting the drive circuit and the detection circuit to the electrodes of the shared piezoelectric element in a time-division manner, b) Differential separation means for extracting the stress-induced signal component by removing the drive signal component in phase using a bridge circuit connected to the common piezoelectric element, c) Frequency separation means that arranges the drive signal component and the stress-induced signal component in different frequency bands and separates them using a filter circuit or a synchronous detection circuit. d) An electrode separation means that divides the electrodes of the shared piezoelectric element into a plurality of electrode regions, connects the drive circuit to the first electrode region, and connects the detection circuit to the second electrode region. A drive and sensing integrated device characterized by including at least one of the following.

5. A drive and sensing integrated device according to any one of claims 1 to 3, wherein the detection circuit includes a voltage follower using an FET input type operational amplifier, and the stress-induced signal component is acquired as the open-circuit voltage of the common piezoelectric element.

6. A drive and sensing integrated device according to any one of claims 1 to 3, wherein the detection circuit includes a charge amplifier circuit that sets the inverting input of the operational amplifier to virtual ground and converts the charge flowing in from the common piezoelectric element via a feedback capacitance into a voltage.

7. A drive and sensing integrated device according to any one of claims 1 to 3, characterized in that it comprises an analysis circuit that, based on the output of the detection circuit, acquires a time-resolved mechanical stress profile within each vibration of the oscillator, and extracts at least one of the swing angle zero crossing, swing angle peak, vibration amplitude, phase, or vibration amplitude attenuation rate from the mechanical stress profile.

8. The drive and sensing integrated device according to claim 7, comprising a control circuit for controlling the drive circuit, wherein the control circuit calculates the mechanical response of the vibrator to the drive signal based on the mechanical stress profile acquired via the detection circuit during or immediately after the application of the drive signal, and determines or corrects at least one of the application timing, application amplitude, application polarity, pulse width, or application probability of the next drive signal to be applied according to the mechanical response.

9. A method for detecting the oscillator phase of a mechanical clock, a) A step of applying a drive signal to at least one common piezoelectric element integrated with a bearing unit supporting the balance shaft of the mechanical clock, or arranged on a balance support member supporting the bearing unit, to generate mechanical displacement or torque pulses; b) A step of obtaining an electrical signal from the shared piezoelectric element that corresponds to the mechanical stress transmitted from the oscillator of the mechanical clock, c) A step of separating the drive signal component corresponding to the drive signal and the stress-induced signal component corresponding to the mechanical stress, d) A step of extracting the phase information of the oscillator from the stress-induced signal component, A method for detecting oscillator phase, characterized by including the following:

10. A method for detecting oscillator phase according to claim 9, characterized in that the mechanical response of the oscillator is obtained from the stress-induced signal component obtained during or immediately after the application of the drive signal, and a closed-loop control is performed to determine or correct at least one of the application timing, application amplitude, application polarity, pulse width, or application probability of the next drive signal to be applied based on the mechanical response.

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