JP2008228375A - Piezoelectric drive device, control method of piezoelectric drive device, electronic timepiece, and electronic apparatus - Google Patents

Abstract

The present invention provides a piezoelectric drive device capable of reliably keeping an overrun with respect to a target drive amount within an allowable range and improving the accuracy of drive control.
A piezoelectric drive device includes a piezoelectric element having a piezoelectric element that vibrates when a drive signal is supplied to the piezoelectric element, and transmits the vibration of the vibrating body to a driven body. Drive amount detection means 70 for detecting the drive amount of the drive body and drive control means for controlling the supply of drive signals to the piezoelectric actuator 20 are provided. The drive control means determines whether or not the driven body has been driven by a predetermined drive amount by the drive amount detection means 70 after inputting a drive signal corresponding to preset first input energy to the piezoelectric actuator 20. To do.
[Selection] Figure 3

Description

  The present invention relates to a piezoelectric driving device, a method for controlling the piezoelectric driving device, an electronic timepiece, and an electronic apparatus.

  When a step movement of a constant angle is performed like a hand movement of an electronic timepiece, an electromagnetic stepping motor is generally used and is widely used as a driving source of the electronic timepiece. When driving a time hand (hand) using an electromagnetic stepping motor, there is a problem of malfunction or stop due to the influence of a magnetic field. In addition, since the driving force is small, a multistage reduction gear train is required, which is disadvantageous for downsizing.

In order to solve these problems, a method of driving a pointer with an ultrasonic motor (piezoelectric actuator) is known (see Patent Documents 1 and 2).
In these Patent Documents 1 and 2, a vibrating body (stator) in which a piezoelectric element is incorporated is pressed against a moving body (rotor) by a pressure spring, and the moving body is rotationally driven. That is, the driving force is transmitted by the frictional force between the vibrating body and the moving body.

By the way, in the electromagnetic stepping motor, the driving amount of the driving target is uniquely determined according to the number of input pulses, whereas the piezoelectric actuator (piezoelectric motor) is driven by the frictional force, so that the driving target for the input energy ( There is a problem that the driving amount of the driven body is not uniquely determined.
For this reason, it is known to detect the driving amount of the driven body using a contact or a sensor (see Patent Document 3).

Japanese Patent Laid-Open No. 10-290579 JP 2000-352588 A Japanese Patent Application Laid-Open No. 11-281772

However, even if the driving amount of the driven body is detected by a contact, a sensor, or the like, there is a time lag between the driving amount and the detection result, and a deviation occurs between the actual driving amount and the detected driving amount. Further, even if the driving is stopped according to the detection result, the driven body does not stop immediately due to the influence of the inertia of the driving system, so that there is a problem that an overrun always occurs.
At this time, as in Patent Document 3, when the timepiece calendar is driven, since the overrun time is very small with respect to the drive time, there is almost no influence by the overrun, and there is no practical problem.

On the other hand, when the time hand is driven by a piezoelectric actuator, the driving time per step is usually made as short as possible in order to ensure battery life. For this reason, the time hand drive has a problem that the ratio of the overrun time to the drive time is increased and the influence on the drive amount is increased as compared with the calendar drive.
For example, when the drive time is set to 1 to several msec per step, if the drive is over several msec due to overrun, the drive amount per step is more than twice the desired drive amount. As a result, there is a problem that high-precision drive control is difficult.

  Such a problem is not limited to an electronic timepiece using a piezoelectric actuator, but is also the same in various electronic devices. That is, the piezoelectric element is excellent in conversion efficiency from electric energy to mechanical energy and responsiveness. For this reason, in recent years, various piezoelectric actuators utilizing the piezoelectric effect of piezoelectric elements have been developed. Since this piezoelectric actuator is applied to the fields of various electronic devices such as a piezoelectric buzzer, an ink jet head of a printer, an ultrasonic motor, an electronic timepiece, and a portable device, the above problem may occur in various electronic devices. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric driving device, a piezoelectric driving device control method, an electronic timepiece, and an electronic device that can reliably keep an overrun with respect to a target driving amount within an allowable range and can improve the accuracy of driving control. There is.

  The piezoelectric driving device of the present invention includes a piezoelectric element having a piezoelectric element that vibrates by supplying a driving signal to the piezoelectric element, and transmitting the vibration of the vibrating body to the driven body, and the driven body Drive amount detecting means for detecting the drive amount of the first actuator and drive control means for controlling the supply of the drive signal to the piezoelectric actuator, wherein the drive control means has a first input energy component preset in the piezoelectric actuator. After the drive signal is input, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means.

According to the present invention, after the piezoelectric actuator has been driven by the first input energy, it is determined whether or not the driven body has been driven by a predetermined drive amount by the drive amount detection means. For this reason, the detected drive amount includes the influence of overrun due to the detection time lag and the inertia of the drive system, and the actual drive amount can be detected. Therefore, drive control based on this drive amount can also be performed with high accuracy.
That is, when driving while detecting the drive amount and stopping the input of the drive signal when the detected drive amount reaches the predetermined drive amount, there is an overrun due to the detection time lag and inertia of the drive system, so detection The drive amount thus deviated from the actual drive amount. For this reason, it is difficult to improve the accuracy of drive control.
On the other hand, in the present invention, since the drive amount is detected after the drive for the preset first input energy is completed, the influence of the overrun due to the detection time lag and the inertia of the drive system is included. The drive amount can be determined with.
Therefore, since the actual drive amount can be detected with high accuracy, the drive amount of the driven body can be controlled with higher accuracy than in the past.

In the present invention, it is preferable that the first input energy is set so that the overrun amount of the driven body after the input of the driving signal is within an allowable range.
According to the present invention, the overrun amount does not exceed the allowable range in that the piezoelectric actuator is driven by the first input energy. For this reason, it can prevent reliably that a to-be-driven body drives exceeding an allowable range, and drive control of a to-be-driven body can be performed with high precision.
In the present invention and each of the following inventions, the overrun amount means an amount exceeding a predetermined movement amount. The predetermined movement amount usually means a value set as a target value of the movement amount (drive amount) when controlling the drive of the driven body. Further, the allowable range of the overrun amount (allowable overrun amount) may be set in advance according to the driving condition of the driven body.

  In the present invention, when the drive amount detection means determines that the driven body is not driven by a predetermined drive amount, the drive control means inputs a drive signal for the second input energy. It is preferable to perform additional drive control.

Since the two types of input energy can be supplied to the piezoelectric actuator, the piezoelectric actuator can be made relatively close to a desired driving amount by supplying and driving the first input energy at the start of driving. When it is determined that the drive amount detected at this time does not reach the predetermined drive amount, the second input energy is supplied to drive (correct), so that the drive amount is closer to the desired drive amount. Can do.
For example, if the magnitude of the first input energy is smaller than the energy required for the desired drive amount, the drive of the first input energy must be performed a plurality of times, and the drive process takes time. The energy required for the desired drive amount is set as a reference. By setting in this way, the drive amount of the piezoelectric actuator can be brought close to the desired drive amount by supplying the first input energy. However, if there is a load fluctuation on the driven body side, There is a case where a desired driving amount is not reached even when driving is performed by supplying input energy. In such a case, if the first input energy is supplied again, there is a high possibility that the desired drive amount will be greatly exceeded.
On the other hand, if the second input energy can be supplied as in the present invention, the first input energy is supplied by setting the second input energy smaller than the first input energy, for example. Even if the desired drive amount has not been reached at the time, the second input energy can be supplied to bring the drive amount of the piezoelectric actuator closer to the desired drive amount, and the driven body can be driven and controlled with high accuracy. .
In addition, when the load of the driven body is increased and the first input energy is supplied but the predetermined driving amount is not significantly reached, the second input energy is set larger than the first input energy. Thus, the second input energy can be supplied to bring the driving amount of the piezoelectric actuator close to the desired driving amount, and the driven body can be driven and controlled with high accuracy.

  In the present invention, the drive control means determines whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means after inputting a drive signal for the second input energy to the piezoelectric actuator. It is preferable to repeat the additional drive control based on the input of the drive signal corresponding to the second input energy until it is determined that it is driven by a predetermined drive amount.

Since the two types of input energy can be supplied to the piezoelectric actuator, the piezoelectric actuator can be made relatively close to a desired driving amount by supplying and driving the first input energy at the start of driving. When it is determined that the drive amount detected at this time does not reach the predetermined drive amount, the second input energy is supplied to drive (correct), so that the drive amount is closer to the desired drive amount. Can do.
That is, when the second input energy is set to be smaller than the first input energy, the number of times of driving (the number of corrections) until the desired driving amount can be reduced compared to the case of driving with only the second input energy. Thus, the desired drive amount can be reached in a short time.
In addition, when driving with only the first input energy, it is difficult to finely adjust the driving amount, and thus it is difficult to make the driving amount sufficiently close to the desired driving amount. However, in the present invention, the driving amount is finely adjusted with the second input energy. Therefore, it is possible to approach the desired driving amount.

  In the present invention, the initial value of the first input energy is set such that the overrun amount of the driven body after the input of the drive signal is stopped is within an allowable range, and the drive control means When it is determined by the amount detection means that the driven body is not driven by a predetermined drive amount, a drive signal for the second input energy is input to perform additional drive control, and the first input energy It is preferable to increase the initial value by a predetermined energy.

Here, the initial value of the first input energy is determined based on the overrun amount of the driven body after the input of the drive signal is stopped in consideration of individual variations of the driven body and the piezoelectric actuator, and repeated driving variations. Is preferably set to be within an allowable range.
In the present invention, the initial value of the first input energy is set so that the overrun amount of the driven body after the input of the drive signal is stopped is within the allowable range. When the piezoelectric actuator is driven, the overrun amount does not exceed the allowable range. For this reason, if the driving amount by the first input energy + allowable range is the target driving amount, the driving amount including the overrun amount when the piezoelectric actuator is driven by the first input energy exceeds the target driving amount. Can be surely prevented.
In addition, if it is determined that the driving is not performed to the predetermined driving amount even if the driving is performed with the first input energy, the additional driving control is performed with the second input energy, so that the target driving amount is further increased. You can get closer.
Further, in this case, since the initial value of the first input energy is increased by the predetermined energy, the piezoelectric actuator is driven with the increased first input energy at the next drive, so that the target drive amount is first The number of drive corrections can be reduced.

Note that the magnitude of the predetermined energy may be the same as the second input energy at the time of the additional drive control, or may be smaller than the second input energy.
However, the second input energy is a parameter that is desired to be set as large as possible without causing an overrun in order to reduce the number of corrections. Therefore, when the second input energy is set to be relatively large, if the second input energy is added to the first input energy to obtain a new initial value of the first input energy, the load fluctuation during the next drive In some cases, the driven body may be overrun only by the first driving by the first input energy.
On the other hand, if the predetermined energy is made smaller than the second input energy, the initial value of the first input energy can be finely adjusted, and as a result, the driven body can be controlled to a desired drive amount. The number of average corrections can be reduced.

  In the present invention, the drive control means determines whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means after inputting a drive signal for the second input energy to the piezoelectric actuator. The additional drive control by inputting the drive signal for the second input energy and the increasing process for the predetermined energy with respect to the initial value of the first input energy are repeated until it is determined that it is driven by the predetermined drive amount. It is preferable.

  The driving of the piezoelectric actuator by supplying the second input energy is repeated until the desired driving amount is reached, and the initial value of the first input energy is increased by the second input energy each time. Even closer. Furthermore, since the initial value of the first input energy is sequentially increased by a predetermined amount, the piezoelectric actuator is driven with the increased first input energy at the next drive, so that the target is not performed without performing additional drive control. The possibility that the drive amount can be increased also increases, and the number of drive corrections can be reduced.

  In the present invention, the drive control unit decreases the initial value of the first input energy by a predetermined energy when the drive amount detection unit determines that the driven body is driven by a predetermined drive amount. It is preferable.

When the initial value of the first input energy is gradually increased, if the initial value is set to the energy applied to the piezoelectric actuator when the predetermined drive amount is reached, there is a load fluctuation on the driven body side, etc. When the next first input energy is applied, the target drive amount may be exceeded from the beginning.
On the other hand, if the initial value of the first input energy is decreased by a predetermined amount, for example, an increase in the first input energy, it is possible to prevent the target drive amount from being exceeded during the next drive.

In the present invention, it is preferable that the second input energy is smaller than the first input energy.
With such a configuration, since the driving amount by the second input energy can be made smaller than the driving amount by the first input energy, the driving amount can be finely adjusted by using the second input energy. Control according to the driving amount can be easily performed.

In the present invention, it is preferable that the second input energy is smaller than an energy amount corresponding to an allowable overrun amount of the driven body.
With such a configuration, it is possible to reliably prevent the drive amount when the second input energy is input from exceeding the allowable range of overrun.

In the present invention, it is preferable that the drive control means controls the input energy by controlling the drive time while keeping the voltage of the drive signal constant.
When the input energy is controlled and the voltage of the drive signal is kept constant and controlled by the drive time, a circuit configuration for varying the voltage becomes unnecessary, and the cost can be reduced.

In the present invention, it is preferable that the drive control means controls the input energy by controlling a voltage while keeping a drive time of a drive signal constant.
If the voltage is controlled with the drive time of the drive signal constant when controlling the input energy, there is no need to increase the drive time in order to increase the input energy, and the drive time is kept constant regardless of the magnitude of the input energy. As a result, the driving time can be shortened. For this reason, for example, when the second hand is driven, it is necessary to complete the driving within one second. However, in the present invention, by adjusting the voltage value, the driving time can be sufficiently shortened and the second hand can be driven sufficiently. It becomes possible.

In the present invention, the drive amount determination means includes a light emitting element and a light receiving element, and the light from the light emitting element is received by the light receiving element when the driven body is driven by a predetermined drive amount. An optical sensor that detects that the driven body has been driven by a predetermined driving amount by changing to a state in which no light is received or changing from a state in which light from the light emitting element is not received by the light receiving element to a state in which light is received. It is preferable that it is comprised.
If the driving amount is detected using an optical sensor, it can be detected in a non-contact manner with respect to the driven body and does not become a load, so that power consumption during driving of the piezoelectric actuator can also be reduced.

In the present invention, the drive amount determination means changes from a state in which the driven body is in contact with the driven body to a non-contact state when the driven body is driven by a predetermined driving amount, or is not in contact with the driven body. It is preferable that the contact member is configured by a contact point that detects that the driven body is driven by a predetermined drive amount by changing from the contact state to the contact state.
If the driving amount is detected by the contact, a sensor such as an optical sensor can be omitted, and the cost can be reduced.

In the present invention, an upper limit value is set for the first input energy, and the upper limit value is obtained by adding the allowable overrun amount to the predetermined drive amount by the maximum value of the drive amount variation when the first input energy is input. It is preferable that the value is set to be smaller than the measured value.
With this configuration, even when the number of corrections increases due to a sudden increase in load, the initial value of the first input energy does not continue to increase according to the number of corrections, and if the upper limit is reached. There is no further increase. For this reason, it is possible to prevent overrun when the driven body is driven with the first input energy next time.

In the present invention, the drive control means inputs the drive signal for the first input energy set in advance to the piezoelectric actuator, and after the predetermined time has elapsed, the drive amount detection means causes the driven body to be driven to a predetermined level. It is preferable to determine whether or not it has been driven by an amount.
If the detection is performed after a predetermined time has elapsed, a detection time lag does not occur, and the determination can be made while including the influence of the inertia of the drive system. For this reason, highly accurate detection becomes possible.

Here, it is preferable that the predetermined time is longer than the time from when the input of the drive signal to the piezoelectric actuator is stopped until the drive system including the driven body is stopped.
According to such a configuration, since the drive amount can be detected after the drive system is completely stopped, a detection time lag does not occur at all, and the determination can be made reliably including the influence of the inertia of the drive system. For this reason, highly accurate detection becomes possible.
In addition, when the driven body is driven at a constant time interval, each of the predetermined times must be set within the predetermined time interval. Specifically, the next driving at a constant time interval is required. It is necessary to set so that the drive of the predetermined drive amount is completed by performing the drive amount detection process after the predetermined time has passed and the correction drive based on the detection. Accordingly, when the driven body is a pointer of a clock and the pointer is operated for 1 second, the predetermined time is naturally set within 1 second and is not set to be larger than 1 second. In this case, the predetermined time is naturally set within 20 seconds, and is not set longer than 20 seconds.

The method for controlling a piezoelectric driving device of the present invention includes a piezoelectric actuator that includes a piezoelectric element and vibrates by supplying a driving signal to the piezoelectric element, and transmits the vibration of the vibrating body to a driven body; A method for controlling a piezoelectric drive device, comprising: a drive amount detection means for detecting a drive amount of a driven body; and a drive control means for controlling the supply of a drive signal to the piezoelectric actuator. After the drive signal corresponding to the first input energy is input, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means.
According to the present invention, the same effect as the piezoelectric driving device can be obtained.

The electronic timepiece of the invention includes the piezoelectric driving device and a time information display unit driven by the piezoelectric driving device.
If the time information display part of the electronic timepiece is driven by the piezoelectric drive device, it can be made thinner than when a stepping motor is used, and the drive amount of the time information display part can be detected with high accuracy. By controlling the driving based on this, it is possible to prevent the display of the timing information from being shifted, and it is possible to give an accurate instruction.

Here, it is preferable that the timing information display unit includes a pointer that is rotationally driven by the piezoelectric driving device.
The timekeeping information display unit driven by the piezoelectric drive device may display calendar information such as a date indicator or day indicator, but when driving an indicator indicating time such as an hour hand, minute hand, second hand, etc. Can be detected with high accuracy, and an electronic timepiece with high indication accuracy can be provided.

  An electronic apparatus according to the present invention includes the piezoelectric driving device and a driving target driven by the piezoelectric driving device.

  If the piezoelectric driving device is used for driving an electronic device, the thickness can be reduced and the driving amount can be detected with high accuracy, so that an accurate operation can be performed.

  According to the piezoelectric drive device, the control method of the piezoelectric drive device, the electronic timepiece, and the electronic apparatus of the present invention, the overrun with respect to the target drive amount can be reliably within the allowable range, and the drive control accuracy can be improved.

[1. First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
In the second and subsequent embodiments to be described later, the same components and components having the same functions as those in the first embodiment described below are denoted by the same reference numerals, and description thereof is simplified or omitted.

[1-1. overall structure]
FIG. 1 is a plan view showing a schematic configuration of an electronic timepiece 1 as an electronic apparatus using the piezoelectric driving device in the present embodiment, and FIG. 2 is a cross-sectional view showing a piezoelectric driving device 10 in the electronic timepiece 1.
1 is a view of the electronic timepiece 1 as viewed from the side opposite to the time display side (the back cover side). In FIG. 1, the upper direction is the 3 o'clock direction of the electronic timepiece 1, and the lower direction is 9 o'clock. Direction, right direction is the 12 o'clock direction, and left direction is the 6 o'clock direction. FIG. 2 is also a view in which the time display side of the electronic timepiece 1 is on the lower side and the back cover side is on the upper side.

  As shown in FIG. 1, the electronic timepiece 1 includes a piezoelectric driving device 10 that drives a pointer that displays time, a battery 2, an IC 5, and a crystal chip 6. The battery 2, the IC 5, the crystal chip 6 and the like are provided on a circuit board (not shown).

[1-2. Configuration of Piezoelectric Drive Device]
As shown in FIGS. 1 to 3, the piezoelectric driving device 10 that drives the pointer includes a piezoelectric actuator 20, a rotor 30, a train wheel 40 that is a drive transmission unit that transmits the rotation of the rotor 30 to the pointer, and the rotor 30. A pressing spring 50 that is a pressing unit that presses against the piezoelectric actuator 20, a ratchet (ratchet mechanism) 60 that regulates the rotation direction of the rotor 30 and the train wheel 40, and a driving amount detection unit 70 that detects the driving amount of the piezoelectric actuator 20. I have.

[1-2-1. Configuration of piezoelectric actuator]
The piezoelectric actuator 20 includes a vibrating body (stator) 21. The vibrating body 21 includes a reinforcing plate 23 made of stainless steel or the like between two rectangular and plate-like piezoelectric elements 22 that has substantially the same shape as the piezoelectric elements 22 and is thinner than the piezoelectric elements 22. It has a sandwiched structure.
As the piezoelectric element 22, lead zirconate titanate (PZT (trademark)), crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, lead zinc niobate, lead scandium niobate, etc. Various types of can be used.

The vibrating body 21 has a contact portion 25 at the end in the width direction of one short side. The abutting portion 25 is obtained by a method such as cutting and molding the reinforcing plate 23, and a tip portion having a gently curved surface is projected from the piezoelectric element. The vibrating body 21 maintains a posture in which the tip of the contact portion 25 is in contact with the outer peripheral surface of the rotor 30.
In the present embodiment, the contact portion 25 is formed at a position that is decentered with respect to the center axis in the width direction of the vibrating body 21, so that the piezoelectric actuator 20 has a weight balance in the width direction of the vibrating body 21. It is configured to be unbalanced and bend easily.

A support portion 26 is formed on one side surface of the piezoelectric actuator 20 in the longitudinal direction. The support portion 26 is integrally formed with the reinforcing plate 23. The support portion 26 is fixed to a ground plate or the like with screws or the like.
In addition, a piezoelectric element circuit board is attached to the support portion 26, and a lead wire extended from the circuit board is connected to a drive electrode provided on the surface of the piezoelectric element 22, so that the piezoelectric element 22 can be driven. Yes.

[1-2-2. Rotor configuration]
The rotor 30 driven in contact with the piezoelectric actuator 20 is rotatably held by the rotor guide body 320. A rotor block is constituted by the rotor 30 and the rotor guide body 320.
As shown in FIG. 3, the rotor guide body 320 is disposed so as to be swingable about the swing shaft 321, and one end of a pressing spring 50 that is a pressing means is in contact with the rotor guide body 320.
The other end of the pressing spring 50 is locked to a fixing pin 51 provided on the ground plate or the like, and the pressing spring 50 disposed between the fixing pin 51 and the rotor guide body 320 is bent to urge the rotor guide body 320. Has been.
The rotor 30 is brought into contact with the contact portion 25 of the piezoelectric actuator 20 with a predetermined contact force (contact pressure) by biasing the rotor guide 320 by the pressing means (the pressing spring 50).

[1-2-3. Configuration of train wheel]
As shown in FIGS. 1 to 3, the train wheel 40 includes a gear 41 that meshes with the pinion 31 of the rotor 30 and a second wheel 42 that meshes with the pinion 410 of the gear 41. A cylindrical pinion 421 is attached to the second wheel & pinion 42, and a minute hand 7 is attached to the cylindrical pinion 421.
A minute wheel 43 is engaged with the pinion pinion 421 of the second wheel 42, and an hour wheel 44 is engaged with the pinion 431 of the minute wheel 43. An hour hand 8 is attached to the hour wheel 44. Each of these gears is pivotally supported by the main plate 3 and the train wheel bridge 4.
When a second hand is provided, the third wheel and the fourth wheel are provided as in a normal timepiece, the rotation of the second wheel 42 is accelerated, and the second pinion that rotates integrally with the fourth wheel is cylindrical. What is necessary is just to arrange | position in the kana 421 and attach a second hand.

The gear 41 is provided with a ratchet gear 411 that rotates integrally with the gear 41. The ratchet gear 411 is formed with sawtooth teeth. The ratchet gear 411, the claw lever 61 that can be engaged with the teeth of the ratchet gear 411, and the pressing spring 62 that presses the claw lever 61 constitute a ratchet mechanism 60.
The claw lever 61 is always pressed by the pressing spring 62 and meshes with the ratchet gear 411. For this reason, the gear 41 can be rotated in the clockwise direction in FIG. 1, but is prevented from rotating by the ratchet gear 411 engaging with the claw lever 61 in the counterclockwise direction.
Accordingly, the ratchet mechanism 60 including the ratchet gear 411, the claw lever 61, and the pressing spring 62 allows the rotor 30 and the train wheel 40 to be rotated only in the second direction, and is restricted from rotating in the first direction. ing. Here, the second direction is a direction in which a pointer provided with the minute hand 7 and the hour hand 8 moves clockwise, and the first direction is a direction in which the pointer moves counterclockwise. In FIG. 3, the second direction is a direction in which the rotor 30 and the ratchet gear 411 rotate in the A direction, and the first direction is a direction in which the rotor 30 and the ratchet gear 411 rotate in the B direction.

The drive amount detection means 70 detects the drive amount of the piezoelectric actuator 20, that is, the rotation amount of the rotor 30 and the train wheel 40.
In the present embodiment, the drive amount detection means 70 includes a transmission gear 72 that meshes with a gear 412 provided integrally with the gear 41, a contact spring 73 that rotates by the transmission gear 72, and a contact spring 73 that contacts the transmission gear 72. A possible drive amount detection circuit board 74 is provided.
The transmission gear 72 and the contact spring 73 speed up the rotation of the gear 41 twice, and the contact spring 73 is configured to rotate twice while the gear 41, that is, the ratchet gear 411 rotates once.

  The contact spring 73 includes a first contact portion 731 and a second contact portion 732 that protrude in opposite directions from the rotation shaft portion. Here, the distance from the rotation center of the contact spring 73 to the first contact portion 731 is shorter than the distance from the rotation center to the second contact portion 73. That is, the rotation locus of the first contact portion 731 is set to be formed inside the rotation locus of the second contact portion 732.

The driving amount detection circuit board 74 includes a first circuit pattern 741 formed in an arc along the rotation locus of the second contact portion 732 and a second circuit pattern formed along the inside of the first circuit pattern 741. 742 and a third circuit pattern 743 formed along the inside of the second circuit pattern 742.
The first circuit pattern 741 is formed over substantially the entire circumference except for the portions where the output terminals H1 and H2 of the patterns 742 and 743 are formed, and the second contact portion 732 is provided so as to be in contact with it. . In addition, since each output terminal H1, H2 is formed on the rotation locus of the 2nd contact part 732, the 2nd contact part 732 is provided so that contact is possible.
Further, the first circuit pattern 741 is provided with a protruding portion 7411 formed at a point-symmetrical position across the rotation center of the contact spring 73 with respect to the output terminals H1 and H2. The projecting portion 7411 extends to the rotation locus of the second contact portion 732 so that the second contact portion 732 can come into contact therewith.
Therefore, when the second contact portion 732 of the contact spring 73 is in contact with the output terminals H1 and H2, the first contact portion 731 is in contact with the protruding portion 7411.

The second circuit pattern 742 and the third circuit pattern 743 are each formed in a substantially arc shape along the outer circumference and the inner circumference of the rotation locus of the first contact portion 731, and further contact alternately projecting toward the rotation locus portion. Portions 7422 and 7432 are provided.
The contact portions 7422 and 7432 are arranged at an interval of about 12 degrees. Therefore, when the ratchet gear 411 rotates 6 degrees, the contact spring 73 rotates 12 degrees, and the first contact part 731 that is in contact with one of the contact parts 7422 and 7432 is connected to the other of the contact parts 7422 and 7432. Will be in contact. The second contact portion 732 is in contact with the first circuit pattern 741 connected to the power supply voltage VDD.
For this reason, when the output terminal H1 is VDD at the start of driving of the piezoelectric actuator 20, if the contact spring 73 rotates 12 degrees, the output terminal H2 becomes VDD, so that the change causes the ratchet gear 411 to rotate by one pitch. It can be detected.
Similarly, when the output terminal H2 is VDD at the start of driving of the piezoelectric actuator 20, if the contact spring 73 rotates 12 degrees, the output terminal H1 becomes VDD, so that the change causes the ratchet gear 411 to rotate by one pitch. It can be detected.

[1-3. Piezoelectric Actuator Drive Control Device and Drive Control Method]
Next, the configuration of the drive control device 100 as drive control means for the piezoelectric actuator 20 will be described with reference to FIG.
In FIG. 4, the drive control apparatus 100 includes an oscillation circuit 11, a frequency dividing circuit 12, a control circuit 13, a drive signal oscillation circuit 14, a waveform shaping circuit 15, and a motor drive circuit (driver) 16. Yes.

The oscillation circuit 11 has a reference oscillation source including a crystal resonator (crystal chip) 6 as a time standard source, and outputs a reference pulse.
The frequency dividing circuit 12 receives the reference pulse output from the oscillation circuit 11, and generates a reference signal (for example, a signal of 1 Hz) based on the reference pulse.

  The control circuit 13 causes the drive signal oscillation circuit 14 to appropriately output a pulse signal based on the reference signal output from the frequency divider circuit 12 to drive the piezoelectric actuator 20. When the second hand is provided, it is necessary to drive the piezoelectric actuator 20 at intervals of 1 second. However, in this embodiment in which the second hand is not provided, the piezoelectric actuator 20 may be driven at intervals of 1 second. However, it may be driven at intervals that do not interfere with the time indication of the minute hand, such as 20-second intervals, 30-second intervals, or 1-minute intervals. In this embodiment, driving is performed at intervals of 20 seconds as will be described later.

  Further, the control circuit 13 is connected to the drive amount detection means 70, and controls the drive signal oscillation circuit 14 to stop the pulse signal using the drive amount detection means 70 as a trigger, or outputs a drive signal to the motor drive circuit 16. Control to stop. Here, when the gear 41 rotates by one tooth (one pitch) of the ratchet gear 411 from the state where the claw lever 61 is engaged with the gear 41, the driving amount detecting means 70 detects the rotation and controls it. The circuit 13 controls the motor drive circuit 16 and the like to stop driving the piezoelectric actuator 20.

The drive signal oscillation circuit 14 is controlled by the control circuit 13 so as to appropriately generate a pulse signal.
The waveform shaping circuit 15 converts the pulse signal output from the drive signal oscillation circuit 14 into a predetermined pulse signal.
The motor drive circuit 16 drives the piezoelectric actuator 20 by applying a drive voltage of a predetermined frequency to the piezoelectric actuator 20 by a predetermined pulse signal output from the waveform shaping circuit 15.
The method for controlling the drive frequency of the piezoelectric actuator 20 is not particularly limited. For example, as disclosed in a patent document (Japanese Patent Laid-Open No. 2006-20445), the frequency of the drive signal supplied to the piezoelectric element 22 is set. The piezoelectric actuator 20 may be driven reliably by sweeping (changing) over a wide range including the driveable frequency range, or as disclosed in a patent document (Japanese Patent Laid-Open No. 2006-33912). A method of changing the frequency of the drive signal so that the phase difference between the frequency of the drive signal supplied to the element 22 and the detection signal obtained from the vibration state of the piezoelectric element 22 becomes a predetermined target phase difference suitable for driving may be used. Alternatively, a method of driving at a fixed frequency set for each temperature in advance may be used.

  As shown in FIG. 4, the control circuit 13 detects a detection signal output from the piezoelectric actuator 20. This detection signal is obtained from a detection electrode (sensor electrode, vibration detection electrode) that is not subject to voltage application due to vibration of the vibration body 21 as a result of the motor drive circuit 16 applying a drive voltage to the drive electrode of the vibration body 21. This is an output signal. Based on this detection signal, the control circuit 13 can confirm the driving state of the piezoelectric actuator 20 and feed back to the driving frequency control.

When the piezoelectric actuator 20 is driven, the contact portion 25 is formed eccentrically at the position of the short side end portion of the reinforcing plate 23, and the contact portion 25 is in contact with the rotor 30 inclined at a predetermined angle. The rotor 30 rotates in the counterclockwise direction (direction A) in FIG. As the rotor 30 rotates, the gear 41 rotates in the clockwise direction (A direction), and the driving of the piezoelectric actuator 20 stops when the claw lever 61 rotates until it engages with the next tooth.
By this rotation, the gears to which the hour hand 8 and the minute hand 7 are attached rotate. Specifically, the gear 41 rotates by 360/60 = 6 degrees. When the gear 41 (ratchet gear 411) rotates 6 degrees, the second wheel 42 rotates 2 degrees and the minute hand 7 rotates 2 degrees. Since the piezoelectric actuator 20 is driven at intervals of 20 seconds, the minute hand 7 is set to rotate 2 degrees at intervals of 20 seconds and to move 6 degrees in one minute, that is, one scale.

[1-3-1. Details of Piezoelectric Actuator Drive Control Method]
Next, details of drive control of the piezoelectric actuator 20 by the drive control device 100 will be described with reference to FIG.
The control circuit 13 of the drive control apparatus 100 drives the piezoelectric actuator 20 by controlling the motor drive circuit 16 and the like at predetermined time intervals. As described above, the control circuit 13 starts driving the piezoelectric actuator 20 at intervals of 20 seconds.
At this time, the control circuit 13 controls the motor drive circuit 16 and inputs a drive signal by the first input energy T1 (step S1). In the present embodiment, the first input energy T1 is set to rotate the contact spring 73 by 12 degrees. Specifically, the motor drive circuit 16 adjusts the energy input to the piezoelectric actuator 20 by the drive signal by keeping the voltage of the drive signal constant and controlling the time. In this embodiment, it is set so that the ratchet gear 411 rotates 6 degrees and the contact spring 73 rotates 12 degrees by outputting a drive signal for a time of about 1.65 msec.

  After inputting the drive signal for the first input energy T1, the control circuit 13 uses the drive amount detection means 70 to determine whether or not it has been driven by a predetermined drive amount (step S2). Specifically, when the output terminal H1 is VDD during the previous drive, that is, before the current drive, it is determined whether or not the drive is driven by a predetermined drive amount depending on whether or not the output terminal H2 becomes VDD. . Similarly, when the output terminal H2 is VDD during the previous drive, it is determined whether or not the output terminal H1 has been driven by a predetermined drive amount depending on whether or not the output terminal H1 has become VDD.

If it is determined as Yes in step S2, it can be determined that the contact spring 73 has rotated 12 degrees. In this case, the initial value of the first input energy T1, that is, the first input energy T1 input in the next step S1 is calculated. That is, the current input energy T1 is decreased by an increase / decrease width ΔT1, which is a predetermined energy amount set in advance, to obtain a new first input energy T1 (step S3).
This is reduced by ΔT1 because there is a possibility of overrun when there is a load fluctuation or the like during the next driving by the first input energy T1.
Then, the driving in this step ends.

On the other hand, if it is determined No in step S2, the control circuit 13 controls the motor drive circuit 16 to perform additional drive control of the piezoelectric actuator 20 by the second input energy T2 (step S4).
Next, the control circuit 13 determines whether or not the current first input energy T1 is greater than or equal to a preset upper limit set value (step S5). And when it determines with Yes at step S5, it returns to determination of step S2.
On the other hand, when it is determined No in step S5, the control circuit 13 adds ΔT1 set in advance to the current first input energy T1, and updates the initial value of the first input energy T1 (step S6). ).

  In step S2, it is determined whether or not the driving by the second input energy T2 in step S4 has been driven by a predetermined driving amount. Then, until it is detected that it has been driven by a predetermined drive amount, the additional drive control by the second input energy T2 (step S4), the comparison process (step S5) with the upper limit set value, and the initial of the first input energy T1 The value update process (step S6) is sequentially repeated.

Note that the second input energy T2 is preferably set to a value as large as possible without causing an overrun in order to minimize the number of additional drive controls, that is, the number of corrections. On the other hand, ΔT1 is preferably set as small as possible so that the first input energy T1 can be finely adjusted. Therefore, the second input energy T2> = ΔT1.
In the present embodiment, the second input energy T2 and ΔT1 are sized to rotate the contact spring 73 once, and to drive the drive signal by about 0.2 msec.

  When such control is performed, the contact spring 73 operates as follows, for example. Since the first contact portion 731 and the second contact portion 732 of the contact spring 73 are formed in a hemispherical shape on the lower surface of the contact spring 73, the first contact portion 731 and the second contact portion 73 in FIGS. The center position of the contact portion 732 is a contact position with each circuit pattern 741, 742, 743.

FIG. 6 shows a state at the end of the previous drive, that is, a state before the current drive. In this example, since the first contact portion 731 of the contact spring 73 is in contact with the contact portion 7432 of the third circuit pattern 743 and the second contact portion 732 is in contact with the first circuit pattern 741, the output terminal H2 is VDD. The output terminal H1 is not VDD.
When the drive signal of the first input energy T1 is input from the motor drive circuit 16 to the piezoelectric actuator 20, the contact spring 73 rotates. Here, for example, as shown in FIG. 7, if the first contact portion 731 of the contact spring 73 remains in contact with the third circuit pattern 743, the output terminal H1 has not changed to VDD, so in step S2. No is determined. For this reason, the control circuit 13 performs additional drive control by the second input energy T2 in step S4.

By this additional drive control, as shown in FIG. 8, when the first contact portion 731 moves between the second circuit pattern 742 and the third circuit pattern 743, the output terminal H1 does not change to VDD, so the step It is determined No again in S2. For this reason, the control circuit 13 performs additional drive control for the second input energy T2 again in step S4.
As shown in FIG. 9, when the first contact portion 731 comes into contact with the contact portion 7422 of the second circuit pattern 742, the output terminal H1 becomes VDD, and Yes is determined in step S2.
Accordingly, it is detected that the contact spring 73 has been rotated by a predetermined drive amount, that is, 12 degrees.

[1-5-1. Simulation example 1]
This embodiment was specifically verified.
That is, in this simulation example, the following parameters were set and the number of corrections (additional drive control times) was verified. That is,
Desired rotation angle (target drive amount) = 2 deg
Overrun allowable angle = 0.4 deg
Repeat variation amount (load fluctuation amount) = 33%
Center value of angle of rotation at initial value of first input energy T1 = 0.5 deg
Center value of angle of rotation at second input energy T2 = overrun allowable angle / (1 + load fluctuation amount) = 0.4 / (1 + 0.33) = 0.30000752 deg
Increase / decrease amount ΔT1 of the first input energy T1 = 0.05 deg
Upper limit value of first input energy T1 = (target driving amount + overrun allowable angle) / (1 + load fluctuation amount) = (2 + 0.4) / (1 + 0.33) = 1.804511 deg
Set to.

FIG. 10 shows a control result when the control according to this embodiment is performed in such a setting.
In FIG. 10, the “first aim” is a driving amount driven by the first input energy T1 in step S1. In the present embodiment, since the first input energy T1 is gradually increased in step S5, the “first aim” is also gradually increased. However, since the upper limit value is set, the first input energy T1 reaches the upper limit value. Then, it does not increase any more and is set near the upper limit value.
In FIG. 10, “corrected drive amount” is the drive amount until “Yes” is determined in step S <b> 3, and is a value in the vicinity of 2 deg which is the target drive amount. Furthermore, the “number of corrections” is the number of times that the additional drive control in step S4 has been executed.

  When the control was performed under such conditions, the probability that the overrun amount exceeded the allowable range was 0%. The average number of corrections was about 1.3.

[1-5-2. Simulation example 2]
On the other hand, FIG. 11 shows the control result when the increase / decrease amount ΔT1 of the first input energy T1 is changed to “0.3 deg” among the conditions of the simulation example 1 and other conditions are not changed.
Also in this case, the probability that the overrun amount exceeds the allowable range was 0%. However, the average number of corrections was about 1.5, which was larger than that in the simulation example 1.
Therefore, rather than setting the second input energy T2 and the increase / decrease amount ΔT1 to be substantially the same as in the simulation example 2, it is better to set ΔT1 to be smaller than the second input energy T2 as in the simulation example 1. This is advantageous in that the average number of corrections can be reduced.

[1-6. Effect of First Embodiment]
The embodiment described above has the following effects.
(1) The drive control device 100 drives the driven body by a predetermined drive amount (target drive amount) by the drive amount detection means 70 after the piezoelectric actuator 20 finishes inputting the drive signal for the first input energy T1. It is determined whether or not it has been done. For this reason, it is possible to detect the driving amount of the driven body with higher accuracy than in the past.
That is, if the drive amount is detected while the piezoelectric actuator 20 is being driven as in the prior art, the detected drive amount deviates from the actual drive amount because there is an overrun due to the detection time lag or the inertia of the drive system. For this reason, it is difficult to improve the accuracy of drive control.
On the other hand, in the present invention, since the drive amount is detected after the drive for the preset first input energy T1 is completed, the influence of the overrun due to the detection time lag and the inertia of the drive system is included. The drive amount can be determined as described above.
Then, the driving for the second input energy T2 and the detection of the driving amount can be repeated until the driving amount becomes a desired driving amount, and the driving amount of the driven body can be controlled with higher accuracy than conventional. .

(2) In the present embodiment, the initial value of the first input energy T1 is updated every time the additional drive control (step S4) is performed with the second input energy T2, and therefore, driving is performed at 1-second intervals in step operation. In the next drive, the updated first input energy T1 can be input to the piezoelectric actuator 20, so that the target drive amount can be driven more quickly.
In addition, since the first input energy T1 is prevented from exceeding the upper limit setting value in step S5, the first input energy T1 becomes unnecessarily large even when the number of corrections increases due to load fluctuation. Therefore, overrun of the driven body can be prevented during the next drive control.

(3) Furthermore, since the second input energy T2 for additional drive control and ΔT1 for updating the initial value of the first input energy T1 can be set to different values, the second input energy can be set as in the first simulation example. By making ΔT1 smaller than T2, the average number of corrections can be reduced.

(4) In addition, when the target drive amount is achieved in step S2, the initial value of the first input energy T1 is decreased in step S3, so that it is reliably prevented that an overrun occurs during the next drive. it can.

(5) Since the drive amount detecting means 70 includes the transmission gear 72, the contact spring 73, and the drive amount detection circuit board 74, the drive amount can be detected with high accuracy. That is, since the drive amount detection means 70 uses the contact spring 73 that rotates in conjunction with the rotation of the ratchet gear 411, the detection timing of the drive amount detection means 70 relative to the rotation timing of the ratchet gear 411 can be made constant, The stop timing of the actuator 20 can also be made constant.

(6) Further, since the transmission gear 72 is used to increase the speed, the resolution of the drive amount detection means 70 can be improved, and the timing of voltage fluctuations at the output terminals H1, H2 can be detected with higher accuracy.

[2. Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In the following embodiments, the same or similar configurations as those of the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted or simplified.

In the second embodiment, as the driving amount detecting means 70B, an extension 613 is provided on the claw lever 61, and a contact 76 that can contact the extension 613 is provided.
That is, the extension portion 613 of the drive amount detection means 70B is formed to extend from the opposite side with respect to the claw portion of the claw lever 61 with the swing shaft 611 interposed therebetween, and the length thereof is the same as that of the claw portion. It is supposed to be several times. For this reason, the extension part 613 moves several times larger than the movement amount of the claw part.

The rotor guide 320 has the rotor 30 supported at one end with the center of the swing shaft 321 interposed therebetween, and a counter balance 322 attached to the other end. By this counterbalance 322, the position of the center of gravity of the rotor guide 320 is adjusted so as to substantially coincide with the center of the swing shaft 321 of the rotor guide 320.
Further, the rotor 30 is pivotally supported by the rotor guide body 320 through a bearing using a ball bearing. Therefore, a gear 31 for transmitting the rotation of the rotor 30 to the train wheel 40 is provided on the outermost periphery. Further, the shape of the rotor guide 320 and the direction of the pressing spring 50 are different from those of the first embodiment. However, these components are functionally the same as those in the first embodiment.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

The claw lever 61 is applied with the power supply voltage VDD through the swing shaft 611. For this reason, when the driving of the piezoelectric actuator 20 in which the pawl lever 61 is engaged with the ratchet gear 411 is started, the potential of the contact 76 is set to other than VDD. Then, when the rotor 30 and the train wheel 40 rotate as the piezoelectric actuator 20 is driven, the claw lever 61 moves along the ratchet teeth, the extension 613 contacts the contact 76, and the potential of the contact 76 becomes VDD. Become. Further, when the rotor 30 rotates, the claw lever 61 engages with the teeth of the next ratchet, the extension 613 is separated from the contact 76, and the potential of the contact 76 becomes other than VDD.
Accordingly, in the drive amount detection means 70B, it is detected that the rotor 30 has moved by a predetermined angle when the potential of the contact 76 once becomes VDD from a state other than VDD and again becomes other than VDD. The drive of the actuator 20 may be stopped. For this reason, in this embodiment, drive control is performed as follows.

[2-2. Details of Piezoelectric Actuator Drive Control Method]
Next, in the present embodiment, details of drive control of the piezoelectric actuator 20 by the drive control device 100 will be described with reference to FIGS.
The control circuit 13 of the drive control apparatus 100 drives the piezoelectric actuator 20 by controlling the motor drive circuit 16 and the like at predetermined time intervals. The drive control apparatus 100 starts driving the piezoelectric actuator 20 at intervals of 1 second or 20 seconds, for example.
At this time, the control circuit 13 controls the motor drive circuit 16 and inputs a drive signal by the first input energy T11 (step S11).

In the present embodiment, the drive amount detection means 70B is in a state in which the extension 613 is in contact with the contact 76 and away from the contact 76 when the claw lever 61 moves along the inclined surface of the teeth of the ratchet gear 411. By detecting it, the drive amount is detected.
That is, as shown in FIG. 15, the extension 613 does not contact the contact 76 on the inclined surface of the tooth of the ratchet gear 411 with which the claw portion of the claw lever 61 contacts, and the output terminal H of the contact 76 is “Lo”. And the region where the extension 613 contacts the contact 76 and the output terminal H of the contact 76 becomes “Hi”.
In the present embodiment, the driving amount is detected after driving only the first input energy T11 and is not always detected during driving. Therefore, when the claw lever 61 is driven with the first input energy T11, If it moves from the Lo region of the currently engaged tooth to the Lo region of the next tooth, it cannot be determined whether or not the ratchet gear 411 has rotated.
For this reason, the first input energy T11 is set as a target drive amount so that the claw lever 61 moves relatively to the boundary portion where the Lo region changes to the Hi region.

The control circuit 13 detects the output of the contact 76 after the drive signal for the first input energy T11 is input by controlling the signal input time in step S11, and the output terminal H changes to “Hi”. It is determined whether or not (step S12).
Here, for example, as shown in FIG. 15A, when the ratchet gear 411 rotates until the claw lever 61 reaches the Hi region by the input of the first input energy T11, “Yes” is determined in step S12. .
On the other hand, when it is determined “No” in step S12, the control circuit 13 inputs a drive signal for ΔT11 which is the second input energy, and performs additional drive control of the piezoelectric actuator 20 (step S13).

Next, the control circuit 13 determines whether or not the first input energy T11 has reached a preset upper limit value (step S14). If the upper limit set value has not been reached, the control circuit 13 adds ΔT11 to T11 to obtain a new initial value of the first input energy T11 (step S15).
In the first embodiment, the second input energy T2 and the increase / decrease amount ΔT1 for updating the initial value of the first input energy T1 can be set to different magnitudes. The input energy and the increase / decrease amount for updating the initial value of the first input energy T1 are set to the same ΔT11.

Then, returning to step S12, it is confirmed whether or not the output terminal H becomes “Hi” by the additional drive control of ΔT11, and steps S12 to S15 are repeated until “Hi”.
Thus, for example, as shown in FIG. 15B, when the claw lever 61 is in the Lo region even when the first input energy T11 is input, the second input energy is increased until the claw lever 61 reaches the Hi region. Additional drive control is performed by ΔT11. Further, every time the additional drive control is performed, the initial value of the first input energy T11 is added by ΔT11. Therefore, when the first input energy T11 is input in the next drive step, the Hi region is reached from the beginning. Can be adjusted.

If it is determined “Yes” in step S12, the control circuit 13 first adjusts the initial value by reducing T11 by ΔT11 (step S16). This is because the first input energy T1 is gradually increased in step S15, so that an overrun or the like occurs when there is a load change or the like, and the ratchet gear 411 can be moved only by the input of the first input energy T1. This is to set a value that is smaller by ΔT1 from the first input energy T1 actually moved by the target drive amount as an initial value of the next input energy T1 in order to prevent the movement by one pitch.
However, in each of the first and second embodiments, control is performed so that the first input energy T1 does not exceed the upper limit set value in steps S5 and S14. There is almost no possibility of doing so. Therefore, the processes of steps S3 and S16 are not essential, and only steps S5 and S14 or only steps S3 and S16 may be executed out of steps S5, S14, S3 and S16.

Next, the control circuit 13 changes the target drive amount in order to move the claw lever 61 in the Hi region relative to the Lo region of the next tooth, and inputs the first input energy T12 to the piezoelectric actuator 20. (Step S17).
Thereafter, the control circuit 13 detects the output of the contact 76 and determines whether or not the output terminal H has changed to “Lo” (step S18).
Here, as shown in FIG. 15A, when the output terminal H becomes “Lo” at the input of the first input energy T12, it is determined as “Yes” in step S18. 13 reduces the first input energy T12 by ΔT12, which is a predetermined energy amount (increase / decrease amount), and sets it as the initial value of the first input energy T12 at the next drive (step S19), and ends the drive control for one step.

On the other hand, if “No” is determined in step S18, the control circuit 13 inputs a drive signal for ΔT12 which is the second input energy, and performs additional drive control of the piezoelectric actuator 20 (step S20).
Next, the control circuit 13 adds ΔT12 to T12 to obtain a new initial value of the first input energy T12 (step S21).
Then, returning to step S18, it is confirmed whether or not the output terminal H becomes “Lo” by the additional drive control of ΔT12, and steps S18, S20, and S21 are repeated until “Lo”.

  Thus, for example, as shown in FIG. 15B, when the claw lever 61 is in the Hi region even when the first input energy T12 is input, the additional driving of ΔT12 is performed until the claw lever 61 reaches the Lo region. Control is performed. Further, each time the additional drive control is performed, the initial value of the first input energy T12 is added by the increase / decrease amount ΔT12. Therefore, when the first input energy T12 is input in the next drive step, the Lo region is initially set. Can be adjusted to reach.

Therefore, the piezoelectric actuator 20 is driven at intervals of, for example, 1 second or 20 seconds, the ratchet gear 411 rotates by one pitch, the claw lever 61 swings, and the contact point 76 changes from Lo → Hi → Lo. The piezoelectric actuator 20 is stopped.
As a result, the train wheel 40 rotates by a predetermined angle every 1 second or 20 seconds, and the hands move stepwise.

[Effects of Second Embodiment]
In this embodiment, the same effects as those of the embodiment described above can be obtained, and the following effects can be obtained.
(2-1) The first input energy T11 corresponding to the target drive amount for moving from the first Lo region to the Hi region, and the first input energy corresponding to the target drive amount for moving from the Hi region to the next Lo region. Since the input energy T12 is set and the drive control is sequentially performed according to different target drive amounts, complicated control for alternately driving with different drive amounts can be easily performed.

(2-2) In the unbalanced state where the center of gravity of the rotor guide 320 is shifted from the center of rotation, if the disturbance is applied to the piezoelectric driving device 10, the rotor guide 320 is easily affected, and the pressing spring 325 is affected. Even if it is pressed, the possibility that the rotor 30 is separated from the contact portion 25 is increased.
On the other hand, in this embodiment, since the unbalance of the rotor guide 320 is set to approximately “0”, even when a disturbance is applied, the rotor 30 and the contact portion are not easily affected by the pressure spring 325. 25 pressed states can be maintained.

(2-3) Since the contact point 76 and the claw lever 61 having the extension 613 that can come into contact with the contact point 76 are used as the drive amount detection means 70B, the drive amount of the ratchet gear 411, that is, the rotor 30 can be set with high accuracy. Can be detected. That is, even if the displacement amount of the claw lever 61 is small, the displacement amount of the extension portion 613 is large, so that it is possible to improve the accuracy of the timing at which the contact portion 76 contacts or leaves the contact point 76.
Moreover, since it can respond only by changing the shape of the claw lever 61, the structure is simple, and the increase in cost can be suppressed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
In the first and second embodiments, as the piezoelectric actuator 20, the one-way drive type in which the contact portion 25 is eccentrically arranged and the rotor 30 is always rotated in one direction is used.
On the other hand, the piezoelectric actuator 20 of this embodiment uses a bidirectional drive type that can rotate the rotor 30 in both directions. That is, the piezoelectric actuator 20 is configured, for example, such that the support portion 26 protrudes from the central portion in the short side width direction of the reinforcing plate 23 and the drive electrode formed on the piezoelectric element is divided into five.
In such a piezoelectric actuator 20, by applying a drive signal to one set of a drive electrode provided at the center in the width direction and two sets of drive electrodes arranged diagonally across the drive electrode, The rotor 30 is rotated in a predetermined direction, and a drive signal is applied to the other set of the drive electrode provided at the center in the width direction and the two sets of drive electrodes arranged diagonally across the drive electrode. Thus, the rotor 30 can be rotated in the opposite direction.

Also in this embodiment, the drive amount detection means 70 of the first embodiment and the drive amount detection means 70B of the second embodiment may be provided.
As a result, the piezoelectric actuator 20 is driven at predetermined time intervals, the drive amount detecting means detects that the ratchet gear 411 has been rotated by one pitch, and the piezoelectric actuator 20 is stopped when it is detected that it has been driven by the predetermined drive amount. To do. At this time, the piezoelectric actuator 20 is controlled so that the rotor 30 rotates in the second direction.
As a result, the train wheel 40 rotates by a predetermined angle every predetermined time. For example, when an hour / minute / second hand is provided as a pointer, the piezoelectric actuator 20 is driven at intervals of one second, the second hand is stepped every second, and the minute hand and hour hand are interlocked with the movement of the second hand. You can also move the needle. When an hour / minute hand is provided as a pointer, the piezoelectric actuator 20 may be driven at intervals of 20 seconds, for example, and the minute hand and hour hand may be stepped at intervals of 20 seconds.

Further, when the rotor 30 is overrun when the piezoelectric actuator 20 is driven, the rotation of the rotor 30 can be returned by driving the piezoelectric actuator 20 in the reverse direction. However, since the ratchet mechanism 60 is provided, the rotor 30 cannot be returned in the reverse direction when the pawl lever 61 is locked to the next tooth in the ratchet gear 411. That is, when the overrun of the rotor 30 is within one pitch of the ratchet gear 411, the overrun is continued until the pawl lever 61 is locked to the ratchet gear 411 and the rotor 30 cannot rotate in the first direction. Can be returned.
In the case of driving in the reverse direction, fine movement drive is performed using a drive signal at the time of additional drive control such as the second input energy T2, T12, etc., and the pawl lever 61 is engaged with the ratchet gear 411. Return to the stop position.

  Also in the piezoelectric actuator 20 of this embodiment, when the drive amount detection means 70 of the first embodiment is provided, drive control may be performed according to the control flow shown in FIG. 5 of the first embodiment. When the drive amount detection means 70B of the second embodiment is provided, drive control may be performed according to the control flow shown in FIGS. 13 and 14 of the second embodiment.

[Effect of the third embodiment]
In the present embodiment as described above, the same effects as the above-described embodiments can be obtained, and the following effects can be obtained.
(3-1) Since the piezoelectric actuator 20 is a bidirectional drive type, the rotor 30 can be rotated in both directions. For this reason, even if the rotor 30 overruns, the rotor 30 can be returned to a position where the rotor 30 cannot be rotated by the ratchet mechanism 60, and the accuracy of the indicated position of the pointer can be improved.

[Fourth Embodiment]
Next, 4th Embodiment of this invention is described based on FIG.
In the present embodiment, an optical sensor is used as the drive amount detection means 70C. Since other configurations are the same as those of the above-described embodiment, description thereof is omitted.

The drive amount detection means 70C includes a transmission gear 72 that meshes with and rotates with a gear 412 that is integral with the gear 41, a detection disc 77 that is rotated by the transmission gear 72, and two optical sensors 78 and 79. ing.
As shown in FIG. 18, each of the optical sensors 78 and 79 includes light emitting diodes (LEDs) 78A and 79A that are light emitting elements, and phototransistors (Tr) 78B and 79B that are light receiving elements.
The LEDs 78A and 79A and the phototransistors 78B and 79B are arranged to face each other with the detection disc 77 interposed therebetween. Therefore, as shown in FIG. 18A, when the through hole 771 locked to the detection disk 77 is disposed between the LEDs 78A and 79A and the phototransistors 78B and 79B, the optical sensor 78 is used. , 79 becomes “Hi”. On the other hand, as shown in FIG. 18B, when the through-hole 771 is not in the optical sensor 78 or the optical sensor 79 portion, the light is blocked by the detection disc 77, so that each sensor output is “Lo”. It becomes.

Here, the detection disc 77 is formed with eight through holes 771 arranged concentrically. These through holes 771 are arranged at equal intervals, that is, at 45 ° intervals.
On the other hand, each of the optical sensors 78 and 79 is arranged concentrically with the through-hole 771, and the central angle connecting the center position of the optical sensors 78 and 79 and the rotation center of the detection disc 77 is 22.5 degrees. Placed in position.
Further, the ratchet gear 411 is provided with 30 saw teeth, and is set to rotate 12 degrees by one-step drive, and the detection disc 77 is increased by 1.875 times to 22. It is set to rotate 5 degrees.

When the drive of the piezoelectric actuator 20 is started, if the output of the optical sensor 78 is “Hi” and the output of the optical sensor 79 is “Lo”, the output of the optical sensor 78 is “Lo” and the output of the optical sensor 79 is The piezoelectric actuator 20 may be driven until it becomes “Hi”.
On the other hand, when the drive of the piezoelectric actuator 20 is started, if the output of the optical sensor 78 is “Lo” and the output of the optical sensor 79 is “Hi”, the output of the optical sensor 78 is “Hi” and the output of the optical sensor 79 is The piezoelectric actuator 20 may be driven until “Lo”.
Thereby, it is detected that the detection disc 77 has rotated 24 degrees, that is, that the ratchet gear 411 has rotated 12 degrees, and the drive amount of one step of the piezoelectric actuator 20 can be detected with high accuracy.

  In addition, since it is the same as that of the said 1st Embodiment in the point which detects the drive amount by the change of the output of each photosensor 78,79, also in this embodiment, control of FIG. 5 of the said 1st Embodiment. Drive control may be performed based on the flow.

[Effect of Fourth Embodiment]
In this embodiment, the same effects as those of the embodiment described above can be obtained, and the following effects can be obtained.
(4-1) Since the optical sensors 78 and 79 are used as the drive amount detection means 70C, the drive amount can be detected without contact with the detection disc 77. For this reason, an increase in load applied to the piezoelectric actuator 20 can be suppressed, and power consumption can be reduced.
Further, since the detection disc 77 interlocked with the ratchet gear 411 is used, the detection timing of the drive amount detection means 70C relative to the rotation timing of the ratchet gear 411 can be made constant, and the stop timing of the piezoelectric actuator 20 can also be made constant.

(4-2) Further, since the transmission gear 72 is used to increase the speed, the resolution of the driving amount detecting means 70C can be improved, and the timing of the signal output fluctuations of the optical sensors 78 and 79 can be detected with higher accuracy.

[5. Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIG.
In this embodiment, as the driving amount detecting means 70D, an extension 613 is provided on the claw lever 61, and optical sensors 78 and 79 for detecting the swinging position of the extension 613 are used. Since other configurations are the same as those of the above-described embodiment, description thereof is omitted.

The extension portion 613 of the drive amount detection means 70D is formed to extend from the opposite side of the claw portion of the claw lever 61 with the swing shaft 611 interposed therebetween, and the length thereof is several times that of the claw portion. It is said that. For this reason, the extension part 613 moves several times larger than the movement amount of the claw part.
Each of the optical sensors 78 and 79 is the same as that of the fourth embodiment, and includes a light emitting diode (LED) that is a light emitting element and a phototransistor that is a light receiving element.
The LED and the phototransistor are opposed to each other with the extension 613 interposed therebetween. A through hole 6131 is formed in the extension portion 613. When the claw portion of the claw lever 61 is engaged with the ratchet gear 411, the through hole 6131 is located at the optical sensor 78 portion, The output of the sensor 78 is “Hi”, and the output of the optical sensor 79 is “Lo”. On the other hand, when the ratchet gear 411 rotates, the through-hole 6131 is positioned at the portion of the optical sensor 79, the output of the optical sensor 79 becomes “Hi”, and the output of the optical sensor 78 becomes “Lo”.

  Therefore, when the driving of the piezoelectric actuator 20 is started, the output of the optical sensor 78 is “Hi” and the output of the optical sensor 79 is “Lo”, and the output of the optical sensor 78 is “Lo” and the output of the optical sensor 79 is “ After becoming “Hi”, the piezoelectric actuator 20 may be stopped again when the output of the optical sensor 78 becomes “Hi” and the output of the optical sensor 79 becomes “Lo”.

  Note that the present embodiment is also the same as the first embodiment in that the driving amount is detected by the change in the output of each of the optical sensors 78 and 79. Therefore, the first embodiment is also the same in the present embodiment. The drive control may be performed based on the control flow of FIG.

[Effect of Fifth Embodiment]
In this embodiment, the same effects as those of the embodiment described above can be obtained, and the following effects can be obtained.
(5-1) Since the claw lever 61 having the extension 613 and the optical sensors 78 and 79 are used as the drive amount detection means 70D, the drive amount of the ratchet gear 411, that is, the rotor 30 can be detected with high accuracy. . That is, even if the displacement amount of the claw lever 61 is small, the displacement amount of the extension 613 is large, so that the timing accuracy detected by the optical sensors 78 and 79 can be improved.
Moreover, since it can respond only by changing the shape of the claw lever 61, the structure is simple, and the increase in cost can be suppressed.

(5-2) Furthermore, since the optical sensors 78 and 79 are used, the driving amount can be detected without contact with the claw lever 61. For this reason, an increase in load applied to the piezoelectric actuator 20 can be suppressed, and power consumption can be reduced.

[8. (Modification)
It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the configuration of the piezoelectric actuator is not limited to a substantially rectangular plate shape, but may be a substantially rhombic plate shape or a substantially parallelogram shaped plate shape. Good. Furthermore, a piezoelectric actuator formed in a truss shape may be used. In other words, the specific configuration of the piezoelectric actuator may be set as appropriate in implementation.

Further, as a pressing means for bringing the rotor 30 into contact with the contact portion 25 of the piezoelectric actuator 20, the pressing spring 50 for biasing the rotor 30 side is provided in each of the above embodiments, but the piezoelectric actuator 20 side is attached. There may be provided pressing means.
Furthermore, the pressing means is not limited to a mechanical means such as a spring, and for example, a pressing means using a magnetic force or the like may be used.

In each of the above-described embodiments, the swing shaft 611 of the ratchet mechanism 60 is formed integrally with the gear 41 that meshes with the rotor 30. However, for example, it may be formed integrally with the rotor 30 or may be integrated with another gear. You may form in. In short, the ratchet mechanism 60 may be provided in either the rotor 30 or the train wheel 40 provided up to the drive target.
Further, in the present invention, the ratchet mechanism 60 is not essential, and the ratchet mechanism 60 may not be provided when the rotor 30 is driven in both directions or when there is no need to restrict the rotation in the reverse direction.

  The configuration of the drive amount detection means is not limited to that of each of the above embodiments. For example, a detection electrode may be provided on the piezoelectric actuator 20, and the drive amount of the piezoelectric actuator 20 may be detected using a detection signal output from the detection electrode, or other detection means may be used.

  The driving target (driven body) is not limited to a gear that is rotationally driven, and may be a movable body that can move linearly, such as a slider that moves linearly via the rotor 30 or the like.

  Furthermore, the drive control method of the piezoelectric actuator 20 is not limited to that of the above embodiment. In short, in the present invention, a drive signal corresponding to the first input energy set in advance corresponding to the target drive amount may be input, and it may be detected whether or not the driven body has been driven to the target drive amount after the input. The processing when the target drive amount has not been reached may be appropriately set according to the type of the driven body.

  The present invention is not limited to the one applied to the electronic timepiece 1 of the above embodiment. That is, the electronic device adopting the piezoelectric driving device of the present invention is not limited to an electronic timepiece such as a wristwatch, a table clock, and a wall clock, but the present invention can be applied to various electronic devices, and particularly downsizing is required. Suitable for portable electronic devices. Here, examples of various electronic devices include a phone having a clock function, a mobile phone, a non-contact IC card, a personal computer, a personal digital assistant (PDA), a camera, and the like. The present invention can also be applied to electronic devices such as a camera without a clock function, a digital camera, a video camera, and a mobile phone with a camera function. When applied to an electronic apparatus having these camera functions, the present invention can be used to drive a lens focusing mechanism, a zoom mechanism, an aperture adjustment mechanism, and the like. In addition, the meter pointer drive mechanism of measuring instruments, the drive mechanism of movable toys and micro robots, the drive mechanism of meter pointers of instrument panels of automobiles, piezoelectric buzzers, inkjet heads of printers, ultrasonic motors, etc. You may use the piezoelectric drive device of invention. In short, the present invention can be applied to various electronic devices having a driving target driven by a piezoelectric actuator.

In the above embodiment, the piezoelectric actuator 20 is used for driving the hands of the electronic timepiece 1, but the present invention is not limited thereto, and may be used for driving a calendar mechanism such as a date wheel of the electronic timepiece 1. In this way, the electronic timepiece 1 can be made thinner by replacing the stepping motor that drives the hands and the date wheel with a piezoelectric actuator, and the piezoelectric actuator is more magnetically affected than the stepping motor. Since it is not easily received, it is possible to achieve high magnetization resistance of the electronic timepiece.
Furthermore, a piezoelectric actuator may be used as a driving source of a doll in a mechanism of a karakuri clock, for example, a karakuri clock that moves a doll according to time.

Although the best configuration, method and the like for carrying out the present invention have been disclosed in the above description, the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

1 is a plan view showing a schematic configuration of an electronic timepiece according to a first embodiment of the present invention. Sectional drawing which shows the principal part in the said electronic timepiece. The top view which shows the structure of a piezoelectric drive device. The block diagram which shows the structure of a piezoelectric drive device. The flowchart which shows the control method of 1st Embodiment. The figure explaining operation | movement of the drive amount detection means of 1st Embodiment. The figure explaining operation | movement of the drive amount detection means of 1st Embodiment. The figure explaining operation | movement of the drive amount detection means of 1st Embodiment. The figure explaining operation | movement of the drive amount detection means of 1st Embodiment. The graph which shows the simulation result of the simulation example 1. FIG. The graph which shows the simulation result of the example 2 of a simulation. The top view which shows the piezoelectric drive device of 2nd Embodiment of this invention. The flowchart which shows the control method of 2nd Embodiment. The flowchart which shows the control method of 2nd Embodiment. The figure explaining operation | movement of the drive amount detection means of 2nd Embodiment. The top view which shows the piezoelectric drive device of 3rd Embodiment of this invention. The top view which shows the piezoelectric drive device of 4th Embodiment of this invention. The figure which shows the structure of the optical sensor in 4th Embodiment. The top view which shows the piezoelectric drive device of 5th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electronic timepiece, 7 ... Minute hand, 8 ... Hour hand, 10 ... Piezoelectric drive device, 13 ... Control circuit, 20 ... Piezoelectric actuator, 21 ... Vibrating body (stator), 22 ... Piezoelectric element, 23 ... Reinforcement plate, 25 ... Contact part, 30 ... rotor, 31 ... rotor kana (gear), 40 ... train wheel, 41 ... gear, 42 ... second wheel, 50 ... pressing spring, 60 ... ratchet mechanism (ratchet), 61 ... claw lever, 62 ... pressing Spring, 70, 70B, 70C, 70D ... Drive amount detection means, 72 ... Transmission gear, 73 ... Contact spring, 74 ... Drive amount detection circuit board, 76 ... Contact, 77 ... Detection disc, 78, 79 ... Optical sensor DESCRIPTION OF SYMBOLS 100 ... Drive control apparatus 320 ... Rotor guide body, 321 ... Swing shaft, 411 ... Ratchet gear, 611 ... Swing shaft, 613 ... Extension part.

Claims (20)

A piezoelectric actuator having a piezoelectric element and having a vibrating body that vibrates by supplying a driving signal to the piezoelectric element, and transmitting the vibration of the vibrating body to a driven body;
Drive amount detection means for detecting the drive amount of the driven body;
Drive control means for controlling the supply of drive signals to the piezoelectric actuator,
The drive control means includes
After the drive signal for the first input energy set in advance is input to the piezoelectric actuator, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means. Piezoelectric drive device. The piezoelectric drive device according to claim 1,
The piezoelectric drive device according to claim 1, wherein the first input energy is set so that an overrun amount of the driven body after the input of the drive signal is stopped is within an allowable range. In the piezoelectric drive device according to claim 1 or 2,
The drive control means includes
When it is determined by the drive amount detection means that the driven body is not driven by a predetermined drive amount, a drive signal corresponding to the second input energy is input to perform additional drive control. Piezoelectric drive device. The piezoelectric drive device according to claim 3.
The drive control means includes
After inputting a drive signal for the second input energy to the piezoelectric actuator, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means,
A piezoelectric drive device that repeats additional drive control by inputting a drive signal corresponding to the second input energy until it is determined that the drive is performed by a predetermined drive amount. The piezoelectric drive device according to claim 1,
The initial value of the first input energy is set so that the overrun amount of the driven body after the input of the drive signal is stopped is within an allowable range,
The drive control means includes
When it is determined by the drive amount detection means that the driven body is not driven by a predetermined drive amount, a drive signal for the second input energy is input to perform additional drive control, and the first A piezoelectric driving device characterized by increasing an initial value of input energy by a predetermined energy. The piezoelectric drive device according to claim 5, wherein
The drive control means includes
After inputting a drive signal for the second input energy to the piezoelectric actuator, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means,
It is characterized by repeating the additional drive control by inputting the drive signal for the second input energy and the increasing process for the predetermined energy with respect to the initial value of the first input energy until it is determined that the drive is performed by the predetermined drive amount. A piezoelectric drive device. In the piezoelectric drive device according to claim 5 or 6,
The drive control means includes
The piezoelectric drive device according to claim 1, wherein when the driven amount detection unit determines that the driven body is driven by a predetermined drive amount, the initial value of the first input energy is decreased by a predetermined energy. In the piezoelectric drive device according to any one of claims 3 to 7,
The piezoelectric driving device according to claim 1, wherein the second input energy is smaller than the first input energy. In the piezoelectric drive device according to any one of claims 3 to 8,
2. The piezoelectric driving device according to claim 1, wherein the second input energy is smaller than an energy amount corresponding to an allowable overrun amount of the driven body. In the piezoelectric drive device according to any one of claims 1 to 9,
The piezoelectric drive device according to claim 1, wherein the drive control means controls the input energy by controlling a drive time while keeping a voltage of a drive signal constant. In the piezoelectric drive device according to any one of claims 1 to 9,
The drive control means controls the input energy by controlling a voltage with a drive time of a drive signal constant, and the piezoelectric drive device according to claim 1. In the piezoelectric drive device according to any one of claims 1 to 11,
The drive amount determination unit includes a light emitting element and a light receiving element, and when the driven body is driven by a predetermined drive amount, the light from the light emitting element is changed from being received by the light receiving element to not receiving light. It is configured by an optical sensor that detects that the driven body is driven by a predetermined driving amount by changing or changing from a state where light from the light emitting element is not received by the light receiving element to a state where the light is received. A piezoelectric driving device characterized by comprising: In the piezoelectric drive device according to any one of claims 1 to 11,
When the driven body is driven by a predetermined driving amount, the driving amount determination means changes from a state in contact with the driven body to a non-contact state or from a state in which the driven body is not in contact with the driven body. A piezoelectric driving device comprising a contact for detecting that a driven body is driven by a predetermined driving amount by changing to a contact state. In the piezoelectric drive device according to any one of claims 1 to 13,
An upper limit is set for the first input energy,
The upper limit value is set such that the maximum value of the variation in the driving amount when the first input energy is input is set to be smaller than a value obtained by adding the allowable overrun amount to the predetermined driving amount. Piezoelectric drive device. In the piezoelectric drive device according to any one of claims 1 to 14,
The drive control means includes
After a drive signal corresponding to the first input energy set in advance is input to the piezoelectric actuator, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means after a predetermined time has elapsed. A piezoelectric drive device characterized by that. The piezoelectric drive device according to claim 15, wherein
The piezoelectric drive device according to claim 1, wherein the predetermined time is longer than a time from when the input of the drive signal to the piezoelectric actuator is stopped until the drive system including the driven body is stopped. A piezoelectric actuator having a piezoelectric element and having a vibrating body that vibrates by supplying a driving signal to the piezoelectric element, and transmitting the vibration of the vibrating body to a driven body;
Drive amount detection means for detecting the drive amount of the driven body;
A control method of a piezoelectric drive device comprising drive control means for controlling supply of a drive signal to the piezoelectric actuator,
After the drive signal for the first input energy set in advance is input to the piezoelectric actuator, it is determined whether or not the driven body is driven by a predetermined drive amount by the drive amount detection means. Control method of piezoelectric drive device.   An electronic timepiece comprising: the piezoelectric driving device according to any one of claims 1 to 16; and a time information display unit driven by the piezoelectric driving device. The timepiece according to claim 18,
The timepiece information display section includes an indicator that is rotationally driven by the piezoelectric driving device.   An electronic apparatus comprising: the piezoelectric driving device according to claim 1; and a driving target driven by the piezoelectric driving device.

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