JP3614111B2 - Piezoelectric actuator, timepiece, portable device, and adjustment method for adjusting pressing force in piezoelectric actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric actuator having a piezoelectric element, a timepiece and a portable device including the piezoelectric actuator, and an adjustment method for adjusting a pressing force in the piezoelectric actuator.
[0002]
[Prior art]
In recent years, various piezoelectric actuators utilizing the piezoelectric effect of piezoelectric elements have been developed and applied to, for example, the field of wristwatch type information equipment.
FIG. 20 is a schematic diagram showing a conventional example of a calendar display mechanism of a wristwatch provided with a piezoelectric actuator. As shown in the figure, the calendar display mechanism includes a piezoelectric actuator A1, a rotor 1, an intermediate wheel 2, and a ring-shaped date wheel 3 on which day and day are written.
The rotor 1 pivotally supported by the base plate (supporting body) 4 is driven to rotate in the direction indicated by the arrow Y in the figure by the piezoelectric actuator A1. An intermediate wheel 2 pivotally supported by the main plate 4 is meshed with the rotor 1, and a date wheel 3 is meshed with the intermediate wheel 2. With this configuration, the date wheel 3 is rotated in the direction indicated by the arrow Z in the figure along with the rotation of the rotor 1 driven by the piezoelectric actuator A1.
[0003]
Next, FIG. 21 shows a detailed configuration of the piezoelectric actuator A1.
As shown in FIG. 21, the piezoelectric actuator A1 has a long plate-like diaphragm 5 formed long in the left-right direction of the drawing. A protruding portion 6 protrudes from the end of the diaphragm 5 in the longitudinal direction toward the rotor 1 side. A support member 7 that supports the diaphragm 5 on the base plate 4 is attached to the upper side of the diaphragm 5 in the drawing, and one end of a spring member 8 is attached to the lower side of the diaphragm 5 in the drawing. The other end of the spring member 8 is supported by a pin 9 erected on the main plate 4. As a result, the diaphragm 5 is urged toward the rotor 1 arranged in the upper part of the figure, and the protrusion 6 is brought into contact with the side surface of the rotor 1.
[0004]
When an alternating current is applied, the diaphragm 5 vibrates in the direction indicated by the arrow X in the drawing in a state where the protrusion 6 is in contact with the rotor 1. This vibration is transmitted to the rotor 1 through the protrusion 6, and the rotor 1 rotates in the arrow Y direction using this as a driving force.
At this time, as described above, by providing the spring member 8, the protruding portion 6 is biased toward the rotor 1, so that the driving force can be stably supplied to the rotor 1.
[0005]
[Problems to be solved by the invention]
The driving force supplied to the rotor 1 is greatly influenced by a force (hereinafter referred to as a pressing force) that urges the protrusion 6 toward the rotor 1 side. For example, if the pressing force is too large, the torque of the rotor 1 increases, while the power required for driving increases, and in the worst case, the rotor 1 cannot be driven to rotate. On the other hand, if the pressing force is too small, the vibration of the diaphragm 5 is not transmitted to the rotor 1 so much that the driving force decreases, and the rotor 1 stops with a slight load, or in the worst case, the rotor 1 is driven to rotate. Can not be.
[0006]
Therefore, at the stage of designing this type of piezoelectric actuator, the shape and elastic characteristics of the spring member 8, the position and shape of the protrusion 6, the diameter of the rotor 1, the position of the pin 9, and the relationship between the rotor 1 and the diaphragm 5 Various conditions such as relative positional relationship need to be calculated strictly.
However, the above-mentioned conditions are inevitably varied at the stage of manufacturing or assembly. Therefore, there is a possibility that the driving characteristics of the rotor 1 predicted in advance in the design stage cannot be realized.
[0007]
The present invention has been made in view of the above circumstances, and a piezoelectric actuator capable of obtaining desired drive characteristics, a timepiece and a portable device including the piezoelectric actuator, and adjusting a pressing force in the piezoelectric actuator. The purpose is to provide an adjustment method.
[0008]
[Means for Solving the Problems]
To solve the above problem,The present inventionThe piezoelectric element and the reinforcing partLong plate-likeThe diaphragm, the support member that supports the diaphragm, and the diaphragm so that the end in the longitudinal direction of the diaphragm is in contact with the drive targetIn the in-plane directionA pressing means for pressing and an adjusting means for adjusting the pressing force by the pressing means, and by supplying a drive signal to the piezoelectric element;Stretch and bend in the in-plane directionVibration toOn the diaphragmAnd drive the drive object by the displacement of the end portion accompanying the vibration.A piezoelectric actuator, wherein the pressing means includes an attachment portion attached to a predetermined support, and an adjustment means contact portion that is displaced in the in-plane direction by the adjustment means while the adjustment means is in contact. And a support member contact portion that presses the support member in the in-plane direction with a pressing force corresponding to a displacement amount of the adjustment means contact portion.
According to this configuration, it is possible to adjust the pressing force that presses the end portion in the longitudinal direction of the diaphragm to the drive target side to a size suitable for efficiently driving the drive target.
[0009]
Of the present inventionOther aspectsInThe attachment portion and the adjustment means contact portion of the pressing means are plate-like members arranged in parallel with the diaphragm, and the adjustment means contact portion is in contact with the adjustment means on a side surface thereof. In the state, it is displaced by the adjusting means.
[0011]
Of the present inventionOther aspectsThe adjusting means is an eccentric cam that is rotatably attached to the support and abuts on the adjusting means abutting portion.. More preferably,The eccentric cam is provided with an adjustment hole into which an adjustment member for rotating the eccentric cam when adjusting is inserted.The
[0013]
Of the present inventionOther aspectsThe pressing means is composed of a member having a longitudinal direction, the support member contact portion of the pressing means is provided at one end in the longitudinal direction, and the adjustment means contact portion of the pressing means is Provided at the other end in the longitudinal direction, the mounting portion of the pressing means is a portion between the support member abutting portion and the adjusting means abutting portion, and the pressing means is rotatable with respect to the support body. Provided to beThe In still another aspect, the pressing means is formed of a member having a longitudinal direction, and the attachment portion of the pressing means is configured so that the pressing means cannot rotate with respect to the support at one end in the longitudinal direction. The adjusting means abutting portion of the pressing means is provided at the other end in the longitudinal direction, and the supporting member abutting portion of the pressing means is the mounting portion and the adjusting means abutting portion. Between the two. In each of these aspects, a configuration in which the member forming the pressing means is curved may be employed.
[0016]
Still other aspectsIn this case, the support member abutting portion of the pressing means and the portion where the support member abuts on the support member abutting portion are configured to engage with each other.The
[0017]
Also,The support memberButAnd formed integrally with the reinforcing portion of the diaphragmIt may be configured as.
[0018]
Of the present inventionOther aspectsInIsThe direction pressed by the pressing means is adjusted to a desired direction by the positional relationship between the attaching portion of the pressing means and the end of the diaphragm.The
[0019]
Still other aspectsThe pressing means and the adjusting means include a guide provided on the support member so as to extend in a direction approaching and moving away from the drive target, and a fixture for fixing the guide to a predetermined support.The In this aspect, the direction in which the guide extends is, for example, a direction in which the pressing unit should press the diaphragm toward the drive target side.
[0021]
The present inventionWatches related toIsMentioned aboveA piezoelectric actuator; a drive circuit for supplying the drive signal to the piezoelectric element; and a power supply for supplying power to the drive circuit;A calendar display wheel driven by the piezoelectric actuator;WithThe
According to this configuration, the pressing force that presses the longitudinal end of the diaphragm toward the drive target side can be adjusted to a size suitable for efficiently driving the drive target. As a result, the calendar display wheel can be efficiently used. Can drive well.
[0022]
The present inventionMobile devices related toIsMentioned aboveA piezoelectric actuator; a drive circuit that supplies the drive signal to the piezoelectric element; a power supply that supplies power to the drive circuit; and the drive target that is driven by the piezoelectric actuator.
[0023]
The present inventionMethod for Driving Piezoelectric Actuator According toThe piezoelectric element and the reinforcing partLong plate-likeThe diaphragm, the support member that supports the diaphragm, and the diaphragm so that the end in the longitudinal direction of the diaphragm is in contact with the drive targetIn the in-plane directionPressing means for pressing, and adjusting means for adjusting the pressing force by the pressing means,The pressing means includes an attachment portion attached to a predetermined support, an adjustment means contact portion that contacts the adjustment means, and a pressing force corresponding to a displacement amount of the adjustment means contact portion. A support member abutting portion that presses in the in-plane direction.Adjusting the pressing force in the piezoelectric actuatorMethodAnd supplying a driving signal to the piezoelectric element.This causes the diaphragm to expand and contract and bend in the in-plane direction.A step of driving the drive object by displacement of the end portion due to vibration; and the adjustment means in contact with the adjustment means contact portion while measuring the drive efficiency of the drive object. Adjusting means contact partBy displacing in the in-plane direction,To increase the driving efficiencyBy the support member contact portionAdjusting the pressing force; andHave
According to this configuration, it is possible to adjust the pressing force that presses the end portion in the longitudinal direction of the diaphragm to the drive target side to a size suitable for efficiently driving the drive target.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a wristwatch provided with a calendar display mechanism driven by a piezoelectric actuator according to the present invention is illustrated.
[0025]
A. overall structure
First, FIG. 1 is a plan view showing a main configuration of a calendar display mechanism incorporating a piezoelectric actuator A in a wristwatch according to an embodiment of the present invention. As shown in the figure, the piezoelectric actuator A includes a diaphragm 10 that expands and contracts in an in-plane direction (a direction parallel to the drawing sheet). The rotor 100 to be driven is rotatably supported by the base plate 103 and is disposed at a position where it abuts on the diaphragm 10. When the outer peripheral surface of the rotor 100 is struck by vibration generated in the diaphragm 10, the rotor 100 rotates clockwise. It is designed to be driven.
The ring-shaped date wheel 50 is connected to the piezoelectric actuator A via a date turning intermediate wheel 40 and a date turning wheel 60 as a reduction gear train and a rotor 100, and is driven to rotate in conjunction with the driving of the rotor 100. It has come to be.
[0026]
Specifically, as described above, when the diaphragm 10 vibrates in the in-plane direction, first, the rotor 100 in contact with the diaphragm 10 is rotated clockwise. The rotation of the rotor 100 is transmitted to the date indicator driving wheel 60 through the date indicator driving intermediate wheel 40, and the date indicator driving wheel 60 rotates the date indicator 50 in the clockwise direction. Thus, transmission of force from the diaphragm 10 to the rotor 100, from the rotor 100 to the speed reduction wheel train, and from the speed reduction wheel train to the date indicator 50 is performed in the in-plane direction. For this reason, the calendar display mechanism can be thinned.
[0027]
FIG. 2 is a cross-sectional view of a timepiece according to one embodiment of the present invention. In the figure, the calendar display mechanism provided with the piezoelectric actuator A described above is incorporated in the mesh portion, and the thickness D into which the calendar display mechanism is incorporated is extremely thin in order to make the entire timepiece thin. A disk-shaped dial 70 is provided on the upper side of the calendar display mechanism. A window portion 71 for displaying the date is provided in a part of the outer peripheral portion of the dial plate 70 so that the date of the date indicator 50 can be seen from the window portion 71. A driving mechanism 73 that drives the hands 72 and a driving circuit (not shown) described later are provided below the dial 70. In this way, various mechanisms built in the wristwatch are hereinafter referred to as movements.
[0028]
B. Configuration of calendar display mechanism
Next, the configuration of the calendar display mechanism will be described with reference to FIG. 1 and FIG. 3 which is a sectional view thereof. In FIG. 3, the base plate 103 is a plate for arranging each component, and the bottom plate 103 ′ is a plate partially having a step with respect to the base plate 103.
[0029]
As illustrated in FIG. 3, a gear 100 c that is coaxial with the rotor 100 and rotated by the rotor 100 is provided above the rotor 100 that is rotationally driven by the piezoelectric actuator A (in the left direction in the drawing). The intermediate date wheel 40 includes a large-diameter portion 4b and a small-diameter portion 4a that is fixed so as to be concentric with the large-diameter portion 4b and slightly smaller in diameter than the large-diameter portion 4b. With the rotation, the large-diameter portion 4b that meshes with the gear 100c is rotated so that the intermediate wheel 40 is rotated. The peripheral surface of the small diameter portion 4a is cut out in a substantially square shape, and a cutout portion 4c is formed.
[0030]
A shaft 41 of the date driving intermediate wheel 40 is formed on the bottom plate 103 ′, and a bearing (not shown) connected to the shaft 41 is formed inside the date driving intermediate wheel 40. Therefore, the date driving intermediate wheel 40 is provided to be rotatable with respect to the bottom plate 103 ′. The rotor 100 also has a bearing (not shown) inside and is rotatably supported with respect to the main plate 103.
[0031]
Next, the date dial 50 has a ring shape, and an internal gear 5a is formed on the inner peripheral surface thereof. The date driving wheel 60 has a five-tooth gear and meshes with the internal gear 5a. A shaft 61 is provided at the center of the date driving wheel 60 and rotatably supports the date driving wheel 60. The shaft 61 is loosely inserted into a through hole 62 formed in the bottom plate 103 ′. The through hole 62 is formed long along the circumferential direction of the date dial 50.
[0032]
As shown in FIG. 1, the plate spring 63 has one end fixed to the bottom plate 103 'and the other end pressing the shaft 61 in the upper right direction in FIG. Accordingly, the leaf spring 63 biases the shaft 61 and the date driving wheel 60. Further, the urging action of the leaf spring 63 prevents the date wheel 50 from swinging.
[0033]
As shown in FIG. 1, the leaf spring 64 has one end fixed to the bottom plate 103 'and the other end formed with a tip 64a bent in a substantially V shape. Further, the contact 65 is arranged so as to come into contact with the leaf spring 64 when the date indicator driving intermediate wheel 40 rotates and the leading end 64a enters the notch 4c. A predetermined voltage is applied to the leaf spring 64, and when the contact is made with the contact 65, the voltage is also applied to the contact 65. Therefore, the date feeding state can be detected by detecting the voltage of the contact 65. Note that a manually driven vehicle that meshes with the internal gear 5a may be provided, and the date indicator 50 may be driven when the user performs a predetermined operation on the crown (not shown).
[0034]
C. Configuration of piezoelectric actuator
Next, the piezoelectric actuator A according to the present embodiment will be described with reference to FIGS.
As shown in FIG. 4, the piezoelectric actuator A includes a long plate-like diaphragm 10 formed long in the left-right direction in the figure, a support member 11 that supports the diaphragm 10 on a ground plate 103 (see FIG. 3), A spring member 12 engaged with the support member 11 and a pressure adjusting cam 13 abutted on the spring member 12 are provided.
[0035]
A projecting portion 36 projects from the end portion 35 in the longitudinal direction of the diaphragm 10 toward the rotor 100 side. By providing such a protrusion 36, it is only necessary to perform an operation such as polishing on the protrusion 36 in order to maintain the state of the contact surface with the rotor 100. Becomes easy. In addition, as the protrusion 36, a conductor or a non-conductor can be used. However, if the protrusion 36 is formed of a non-conductor, the piezoelectric element 30, 31 can be prevented from being short-circuited.
[0036]
Further, the protrusion 36 has a curved surface shape that protrudes toward the rotor 100 as viewed in a plan view. By forming the protrusion 36 that contacts the rotor 100 in a curved shape in this way, the outer peripheral surface of the rotor 100 that is a curved surface even when the positional relationship between the rotor 100 and the diaphragm 10 varies due to dimensional variation or the like. And the curved projection portion 36 do not change so much. Therefore, the contact between the rotor 100 and the protrusion 36 is maintained in a stable state.
[0037]
One end portion 11 a of a substantially L-shaped support member 11 is attached in the vicinity of the central portion in the longitudinal direction of the diaphragm 10. The support member 11 is bent from one end portion 11a to the rotor 100 side from a direction substantially orthogonal to the longitudinal direction of the diaphragm 10, and the other end portion 11b of the bent support member 11 is grounded by the shaft portion 11c. (See FIG. 1). By trying to rotate the support member 11 in the direction of the arrow W in the figure, the diaphragm 10 can be reliably pressed against the rotor 100.
Note that the support member 11 may be integrally formed with an auxiliary plate 32 described later that constitutes the vibration plate 10.
[0038]
One end 12 a of the spring member 12 is engaged with a portion 11 d that extends substantially parallel to the longitudinal direction of the diaphragm 10 in the support member 11. Here, as shown in FIG. 3, the main part of the spring member 12 is provided so as to fit between the diaphragm 10 and the ground plate 103 so as not to disturb the vibration of the diaphragm 10. Only the one end portion 12a described above is erected on the spring member 12 so as to extend upward in the figure (left direction in FIG. 3). The spring member 12 is rotatably supported by the base plate 103 by the shaft portion 12b at a portion between the one end portion 12a and the other end portion 12c.
[0039]
As shown in FIG. 4, the other end 12 c of the spring member 12 is in contact with an eccentric-shaped press adjusting cam 13. The pressing adjustment cam 13 is fixed to the base plate 103 by a screw 13a during normal operation. However, when adjusting the pressing force, the screw 13a is loosened and can rotate about the screw 13a. Further, the pressing adjustment cam 13 is provided with a terminal guide hole 13b for inserting an adjusting terminal (not shown) when adjusting the pressing force. As will be described later, this pressing force can be adjusted manually or by an automatic assembly machine that automatically assembles a wristwatch movement.
[0040]
FIG. 5 is a cross-sectional view showing a state in which the pressing adjustment cam 13 is fixed to the main plate 103. As shown in FIG. 5, the pressing adjustment cam 13 has a through hole 13 e, and a screw receiving portion 13 d erected on the base plate 103 is inserted into the through hole 13 e. On the inner side of the screw receiving portion 13d, a screw thread that engages with the screw 13a is formed.
[0041]
A spacer 113 c is interposed between the pressure adjusting cam 13 and the ground plate 103, and the pressure adjusting cam 13 is fixed to the ground plate 103 by tightening the screw 13 a. When adjusting the pressing force, the screw 13a is loosened, so that the pressing adjustment cam 13 can rotate around the screw 13a or the screw receiving portion 13d. At this time, a substantially L-shaped adjusting terminal 13f is inserted into the terminal guide hole 13b by the adjusting operator, and the adjusting terminal 13e is moved by the adjusting operator's hand, whereby the pressing adjusting cam 13 rotates. Be made.
[0042]
For example, if the pressing adjustment cam 13 is rotated and brought into contact with the other end portion 12c as shown by the dotted line shown in FIG. 4, the other end portion 12c of the spring member 12 rotates clockwise in the drawing around the shaft portion 12b. Accordingly, the force by which the one end portion 12a of the spring member 12 presses the portion 11d of the support member 11 upward is increased. Further, when the pressing adjustment cam 13 is brought into contact with the other end portion 12c as shown by a solid line in the drawing, the other end portion 12c of the spring member 12 is displaced counterclockwise around the shaft portion 12b, thereby The force with which the one end portion 12a of the spring member 12 presses the portion 11d of the support member 11 upward is reduced.
And if the force which presses the support member 11 upwards increases, the pressing force in which the projection part 36 of the diaphragm 10 will press the rotor 100 will increase. On the other hand, when the force that presses the support member 11 upward decreases, the pressing force with which the protrusion 36 of the diaphragm 10 presses the rotor 100 decreases.
Thus, by adjusting the position of the other end portion 12c by rotating the pressing adjustment cam 13, the pressing force applied to the rotor 100 by the protrusion 36 can be adjusted, and thereby the drive adjustment of the rotor 100 can be performed. It becomes possible.
[0043]
Next, the configuration of the diaphragm 10 will be described.
As shown in FIG. 6, the diaphragm 10 is between the two rectangular piezoelectric elements 30, 31 and has substantially the same shape as the piezoelectric elements 30, 31 and is thicker than the piezoelectric elements 30, 31. A laminated structure in which a reinforcing plate 32 such as thin stainless steel is disposed.
By disposing the reinforcing plate 32 between the piezoelectric elements 30 and 31 in this way, damage to the diaphragm 10 due to external impact force due to overamplitude or dropping of the diaphragm 10 is reduced, and durability is improved. It is improving. Further, by using a reinforcing plate 32 that is thinner than the piezoelectric elements 30 and 31, the vibration of the piezoelectric elements 30 and 31 is prevented as much as possible. In addition, if the support member 11 mentioned above is integrally formed with the said reinforcement board 32, a manufacturing process can be simplified.
[0044]
In addition, electrodes 33 are arranged on the surfaces of the piezoelectric elements 30 and 31 arranged above and below so as to cover almost the entire surface of the piezoelectric elements 30 and 31. A drive signal is supplied from the drive circuit 500 to the piezoelectric elements 30 and 31 via these electrodes 33.
[0045]
Here, as the piezoelectric elements 30 and 31, lead zirconate titanate (PZT (trademark)), crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, lead zinc niobate, Various materials such as lead scandium niobate can be used. Here, the composition formula of lead zinc niobate is [Pb (Zn_1/3-Nb_2/3) O₃  )_1-X(PbTiO₃)_X(Where X varies depending on the composition, and X = 0.09), and the composition formula of lead scandium niobate is [{Pb ((Sc_1/2-Nb_1/2)_1-X  Ti_X) O₃(Where X varies depending on the composition, and X = 0.09).
[0046]
When the polarization directions of the piezoelectric elements 30 and 31 are reversed, for example, as shown in FIG. 7, the potentials of the upper surface, the center, and the lower surface are + V, 0, and + V (or −V, 0, and −V), respectively. When a drive signal is applied from the drive circuit 500, the plate-like piezoelectric element is displaced so as to expand and contract. In this embodiment, such displacement due to expansion and contraction is used. When the polarization directions of the piezoelectric elements 30 and 31 are the same, a voltage is applied so that the potentials of the upper surface, the center, and the lower surface are + V, 0, and −V (or −V, 0, and + V), respectively. do it.
[0047]
When the AC drive signal is applied to the piezoelectric elements 30 and 31 from the drive circuit 500 via the electrodes 33 and 33, the diaphragm 10 configured in this manner expands and contracts in the longitudinal direction. Vibration occurs. At that time, as shown in FIG. 8, the piezoelectric elements 30 and 31 expand and contract in the longitudinal direction, so that the diaphragm 10 vibrates by longitudinal vibration that expands and contracts in the longitudinal direction. It will vibrate in the direction indicated by arrow X in FIG.
As described above, when the diaphragm 10 is electrically excited by the longitudinal vibration by applying the drive signal to the piezoelectric elements 30 and 31, the rotational moment about the center of gravity of the diaphragm 10 due to the unbalance of the weight balance of the diaphragm 10. Will occur. As shown in FIG. 9, this rotational moment induces a bending vibration in which the diaphragm 10 swings in the width direction (vertical direction in FIG. 4). In the present embodiment, in order to induce a larger flexural vibration, a larger rotational moment is generated by providing the balance portion 18 at the end portion 16 on the opposite side to the side on which the projection portion 36 of the diaphragm 10 is provided. I am doing so.
[0048]
In this way, longitudinal vibration and bending vibration are generated in the vibration plate 10, and both are combined, so that the contact portion of the protrusion 36 of the vibration plate 10 with the rotor 100 is elliptical as shown in FIG. 10. It will move along the trajectory. Then, when the protrusion 36 draws an elliptical orbit, the protrusion 36 comes into pressure contact with the rotor 100 when the protrusion 36 is in a position swelled toward the rotor 100, while the protrusion 36 is on the rotor 100 side. When the protrusion 36 is in the position swollen from the position retracted, the protrusion 36 is separated from the rotor 100 (or the pressing force is reduced even if the protrusion 36 is in contact). Therefore, the piezoelectric actuator A rotationally drives the rotor 100 in the displacement direction of the protrusion 36 while the pressing force between the two is large, that is, when the protrusion 36 is in a position swelled to the rotor 100 side.
[0049]
D. Drive operation of piezoelectric actuator
Hereinafter, the driving operation of the piezoelectric actuator A configured as described above will be described with reference to FIG.
As shown in the figure, the drive circuit 500 includes an midnight detection unit 501, a control circuit 503, a date feed detection unit 502, and an oscillation circuit 504. The midnight detection means 501 is a mechanical switch incorporated in the drive mechanism 73 (see FIG. 2), and outputs a control signal to the output control circuit 503 at midnight. Further, the date feed detecting means 502 mainly includes the leaf spring 64 and the contact 65 (see FIG. 1) described above. When the leaf spring 64 and the contact 65 are in contact with each other, that is, when the date feed end is detected. A control signal is output to the control circuit 503.
[0050]
The control circuit 503 outputs an oscillation control signal to the oscillation circuit 504 based on the control signal supplied from the midnight detection unit 501 and the control signal supplied from the date feed detection unit 502. The oscillation control signal rises from a low level to a high level when midnight is detected by the midnight detection means 501. After that, when the date feed end is detected by the date feed detection means 502, the oscillation control signal starts from the high level. Fall to low level.
The oscillation circuit 504 is supplied with power when the oscillation control signal is at a high level, and is stopped when the oscillation control signal is at a low level. The piezoelectric elements 30 and 31 are supplied via 33 and 33. In response to the supply of the drive signal, the piezoelectric element performs the expansion and contraction operation as described above.
[0051]
As described above, the intermediate date wheel 40 rotates once per day, but this period is a limited time starting from midnight. Therefore, the oscillation circuit 504 only needs to oscillate only during the period. In the drive circuit 500 of this example, by controlling the power supply to the oscillation circuit 504 with a high-level or low-level oscillation control signal, the oscillation circuit 504 is in a period during which it is not necessary to rotate the intermediate date wheel 40. The operation of 504 is completely stopped. Accordingly, power consumption of the oscillation circuit 504 can be reduced.
[0052]
E. Operation of the calendar display mechanism
Next, the automatic update operation of the calendar display mechanism provided with the piezoelectric actuator A having the above configuration will be described with reference to FIGS.
At midnight on each day, it is detected by the midnight detection means 501 shown in FIG. 11 that the time has reached midnight, and an oscillation control signal is output from the control circuit 503 to the oscillation circuit 504. As a result, a drive signal having a predetermined frequency is supplied from the oscillation circuit 504 to the piezoelectric elements 30 and 31 via the electrodes 33 and 33.
[0053]
When a drive signal from the drive circuit 500 is applied to the electrodes 33 and 33, the piezoelectric elements 30 and 31 are bent and vibrated by expansion and contraction, and the diaphragm 10 is vibrated longitudinally.
At this time, when the polarization directions of the piezoelectric elements 30 and 31 are the same as described above, the potentials of the upper surface, the center, and the lower surface are + V, 0, and −V (or −V, 0, and + V), respectively. A voltage is applied so that Further, when the polarization directions of the piezoelectric elements 30 and 31 are reversed, the voltages are applied so that the potentials of the upper surface, the center, and the lower surface are + V, 0, and + V (or −V, 0, and −V), respectively.
When the diaphragm 10 is electrically excited in the vertical direction, bending vibration is mechanically induced by the unbalance of the weight balance of the diaphragm 10. Then, when the longitudinal vibration and the bending vibration are combined, the protrusion 36 is displaced along the elliptical orbit and drives the rotor 100.
[0054]
As the piezoelectric actuator A is driven by the drive circuit 500 in this way, the rotor 100 shown in FIG. 1 rotates in the clockwise direction in FIG. 4, and accordingly, the intermediate wheel 40 rotates in the counterclockwise direction. To start.
[0055]
Here, the drive circuit 500 is configured to stop the supply of the drive signal when the leaf spring 64 and the contact 65 shown in FIG. 1 contact each other. In a state where the leaf spring 64 and the contact 65 are in contact with each other, the distal end portion 64a enters the cutout portion 4c. Therefore, the date driving intermediate wheel 40 starts rotating from such a state.
[0056]
Since the date driving wheel 60 is urged clockwise by the leaf spring 63, the small diameter portion 4a rotates while sliding on the teeth 6a, 6b of the date driving wheel 60. On the way, when the notch 4c reaches the position of the tooth 6a of the date indicator driving wheel 60, the tooth 6a meshes with the notch 4c.
[0057]
Next, when the intermediate date wheel 40 continues to rotate counterclockwise, the intermediate date wheel 60 rotates in the clockwise direction by one tooth, that is, “1/5” lap in conjunction with the intermediate date wheel 40. Move. Further, in conjunction with this, the date dial 50 is rotated clockwise by one tooth (corresponding to a date range for one day). Note that, on the last day of the month in which the number of days in the month is less than “31”, the above operation is repeated a plurality of times, and the correct date based on the calendar is displayed by the date wheel 50.
[0058]
When the intermediate date wheel 40 continues to rotate counterclockwise and the notch 4c reaches the position of the tip 64a of the leaf spring 64, the tip 64a enters the notch 4c. Then, the leaf spring 64 and the contact 65 come into contact with each other, the supply of the drive signal is finished, and the rotation of the intermediate date wheel 40 is stopped. Therefore, the intermediate date wheel 40 rotates once per day.
[0059]
F. Procedure for adjusting the amount of pressing force
Next, a procedure for adjusting the magnitude of the pressing force supplied to the rotor 100 by rotating the pressing adjustment cam 13 will be described.
In the movement assembly process of the wristwatch, the adjustment operator sets the movement on which the actuator A is mounted on a rotation speed sensor (not shown) for detecting the rotation speed of the rotor 100. As this rotation speed sensor, for example, a sensor that detects the rotation speed without contact with the detection target, such as a laser displacement meter, is desirable.
[0060]
Next, the adjustment operator performs a predetermined operation to shift the drive circuit 500 to the adjustment mode. In response to this, an oscillation control signal is output from the control circuit 503 to the oscillation circuit 504, and a drive signal having a predetermined frequency is supplied from the oscillation circuit 504 to the piezoelectric elements 30 and 31 via the electrodes 33 and 33. As a result, the vibration plate 10 vibrates and the rotor 100 starts to be driven as the protrusion 36 is displaced.
[0061]
Next, the adjustment operator loosens the screw 13a with a flat-blade screwdriver, and in this state inserts the adjustment terminal 13e into the terminal guide hole 13b and gradually rotates the pressing adjustment cam 13.
At this time, the adjustment operator causes the pressure adjustment cam 13 to rotate at least one rotation while monitoring the detection value of the rotation speed sensor with a monitor or the like (not shown). Then, the direction of the pressure adjusting cam 13 is adjusted so that the detection value of the rotation speed sensor becomes the maximum.
When such an orientation is determined, the adjustment operator tightens the screw 13 a to fix the pressing adjustment cam 13 to the main plate 103.
The pressing force can be adjusted by an automatic assembling machine that automatically assembles the movement of the wristwatch in addition to the manual adjustment as described above.
[0062]
G. Adjusting the pressing direction
Now, the adjusting operator can adjust the magnitude of the pressing force as described above, but from the viewpoint of improving the driving efficiency of the rotor 100, in which direction the pressing force is applied. This is also an important condition.
As a result of considering this point, the present applicant has derived that the direction of the pressing force (hereinafter referred to as the pressing direction) can be adjusted by the positional relationship between the rotor 100 and the support member 11. did. Hereinafter, three different pressing directions will be described as examples.
[0063]
FIG. 12 is a plan view showing the positional relationship between the piezoelectric actuator A and the rotor 100 when a pressing force is applied in a direction parallel to the vibration direction of the diaphragm 100.
A straight line P <b> 1 indicated by a dotted line in the drawing is a straight line connecting the center of the shaft portion 11 c of the support member 11 and a point where the protrusion 36 contacts the rotor 100 (hereinafter referred to as a contact point). This straight line P <b> 1 is in a relationship orthogonal to the vibration direction of the diaphragm 10. The diaphragm 10 tends to rotate counterclockwise about the shaft portion 11c as a result of a force applied in the upward direction of the drawing by the spring member 12. That is, the protrusion 36 applies a pressing force to the rotor 100 in the direction of arrow L in the figure.
[0064]
Next, FIG. 13 is a plan view showing the positional relationship between the piezoelectric actuator A and the rotor 100 when a pressing force is applied in a direction orthogonal to the vibration direction of the diaphragm 100. A straight line P2 indicated by a dotted line in the figure is a straight line connecting the center of the shaft portion 11c and the contact point, like the straight line P1. The straight line P2 is in a relationship parallel to the vibration direction of the diaphragm 10. As a result of the force applied in the upward direction of the drawing by the spring member 12, the diaphragm 10 tends to rotate clockwise about the shaft portion 11c. That is, the protrusion 36 applies a pressing force to the rotor 100 in the direction of arrow M in the figure.
[0065]
Next, FIG. 14 is a plan view showing a positional relationship between the piezoelectric actuator A and the rotor 100 when a pressing force is applied in a direction toward the substantially center point of the rotor 100. A straight line P3 indicated by a dotted line in the figure is a straight line connecting the center of the shaft portion 11c and the contact point, like the straight line P11. This straight line P3 is in a relationship of making an angle of approximately 45 ° with the vibration direction of the diaphragm 10. The diaphragm 10 tends to rotate counterclockwise about the shaft portion 11c as a result of a force applied in the upward direction of the drawing by the spring member 12. That is, the protrusion 36 applies a pressing force to the rotor 100 in the direction of arrow N in the figure.
[0066]
The direction of the pressing force illustrated above is merely an example. Actually, the optimal pressing direction depends on conditions such as the shape and elastic characteristics of the spring member 12, the position and shape of the protrusion 36, the diameter of the rotor 100, and the like. Is to be determined.
[0067]
As described above, in the present embodiment, in the thin piezoelectric actuator A that can be installed in a limited space such as a wristwatch, the pressing force applied to the rotor 100 by the piezoelectric actuator A can be easily adjusted. . Also,
By changing the positional relationship between the rotor 100 and the support member 11, a desired pressing direction can be realized.
If an appropriate pressing force can be applied to the rotor 100 in this way, the calendar display mechanism can be driven efficiently.
[0068]
H. Modified example
The present invention is not limited to the above embodiment, and various modifications as exemplified below are possible.
(1) Shape of the spring member 12
The shape of the spring member 12 exemplified in the embodiment can take various shapes depending on the empty space of the device on which the piezoelectric actuator A is mounted.
For example, if there is an empty space between the diaphragm 10 and the ground plate 103 shown in FIG. 3, the spring member 12 may be provided in that space. FIG. 15 is a plan view showing the configuration of the piezoelectric actuator A in this case. As shown in the figure, the spring member 12 is curved so as to be substantially U-shaped in the direction toward the diaphragm 10 from the vicinity of the shaft portion 12b. Even in such a configuration, the diaphragm 10 can be pushed upward (upward in the drawing) via the spring member 12 by rotating the pressing adjustment cam 13.
[0069]
Moreover, although the spring member 12 was rotatable around the shaft portion 12b, it is not always necessary.
FIG. 16 is a diagram illustrating a configuration of the piezoelectric actuator A when the spring member 12 is fixed to the ground plate 103. In the figure, the spring member 12 is fixed to the base plate 103 so as not to be displaced by a shaft portion 12d. At this time, the spring member 12 is in a state where a portion between the shaft portion 12 d and the other end 12 c is bent in a convex manner in the direction of the diaphragm 10, and the other end 12 c is in contact with the pressing adjustment cam 13. Yes. That is, the press adjusting cam 13 plays a role of suppressing a force that the spring member 12 tries to restore in the direction of the diaphragm 10 by elasticity. Also in this case, the force for pushing up the diaphragm 10 upward (upward in the drawing) via the spring member 12 can be adjusted by rotating the pressing adjustment cam 13.
[0070]
(2) Form of pressing means and adjusting means
In the embodiment, the spring member 12 is used as a pressing unit that applies a pressing force to the rotor 100, and the pressing adjustment cam 13 is used as an adjusting unit that adjusts the pressing force. However, it is not limited to this, For example, it is good also as the following structures.
FIG. 17 is a plan view showing the configuration of the piezoelectric actuator A. FIG.
As shown in the figure, the support member 11 is provided with a guide 11 e in a direction substantially parallel to the vibration direction X of the diaphragm 10. The guide 11e is provided so as to penetrate the support member 11 in the direction perpendicular to the paper surface, and the support member 11 is fixed to the base plate 103 by shaft portions 11f and 11g inserted into the guide 11e. The adjustment operator can adjust the pressing force applied to the rotor 100 by displacing the support member 11 in various directions in the direction in which the guide 11e extends (the horizontal direction in the drawing). In this case, the direction of the pressing force is the direction indicated by the arrow N in the figure. Then, the adjustment operator may fix the support member 11 with the shaft portions 11f and 11g at a position where desired driving characteristics can be obtained.
[0071]
Further, as shown in FIG. 18, a guide 11 e may be provided in a direction substantially orthogonal to the vibration direction X of the diaphragm 10. In this case, the direction of the pressing force is the direction indicated by the arrow M in the figure.
[0072]
In addition, as shown in FIG. 19, a guide 11 e may be provided in a direction that forms an angle of approximately 45 ° with the vibration direction X of the diaphragm 10. In this case, the direction of the pressing force is the direction indicated by the arrow N in the figure.
However, the direction of the pressing force described above is merely an example, and as described in the embodiment, in practice, an optimal pressing direction may be determined according to various conditions.
[0073]
(3) Positional relationship between the rotor 100 and the diaphragm 10
Depending on the dimensions of the diaphragm 10, the magnitude relationship between the resonance frequency of the longitudinal vibration and the resonance frequency of the bending vibration may be different from that assumed in the embodiment. When such a diaphragm 10 is employed, the elliptical orbit of the protrusion 36 due to the displacement of the diaphragm 10 is in the reverse direction, and the direction in which the rotor 100 is driven is counterclockwise in FIG. 4 (the direction opposite to the above embodiment). It becomes. Therefore, in such a case, it is necessary to change the positional relationship between the rotor 100 and the diaphragm 10 from the above embodiment in accordance with the required driving direction.
Further, the number of intermediate gears interposed between the rotor 100 and the date driving wheel 50 is not limited to that illustrated in the embodiment, but is arbitrary. Since the direction in which the rotor 100 should be rotated is determined by the number of intermediate gears, the positional relationship between the rotor 100 and the diaphragm 10 needs to be changed accordingly.
[0074]
(4) Shape of diaphragm 10
In the above-described embodiment, the rectangular diaphragm 10 is used. However, the shape of the diaphragm 10 is not limited to the rectangular shape, and may be a shape having a longitudinal direction, for example, a trapezoidal shape, Various shapes such as a parallelogram shape, a rhombus shape, and a triangle shape can be used.
[0075]
(5) Variations in equipment equipped with piezoelectric actuators
In the above-described embodiment, the case where the piezoelectric actuator A is employed as a drive source of a calendar display mechanism mounted on a wristwatch has been described as an example. However, the present invention is not limited to this, The present invention can be applied to various types of devices, for example, a driving mechanism of an amusement device such as a toy or a driving mechanism of a small blower. In addition, as described above, the piezoelectric actuator A can be reduced in thickness and size, and can be driven with high efficiency. Therefore, the piezoelectric actuator A is suitable as an actuator mounted on a power source-driven portable device or the like.
[0076]
(6) Driving mode of piezoelectric actuator A
Further, in the above-described embodiment, the case where the rotor 100 in contact with the protrusion 36 is rotationally driven by the vibration of the diaphragm 10 is illustrated. It is also possible to apply the present invention to a linear actuator.
[0077]
【The invention's effect】
As described above, according to the present invention, it is possible to easily adjust the pressing force with which the piezoelectric actuator presses the drive target. As a result, it is possible to realize a suitable drive characteristic without being affected by the above-described variations occurring during manufacture or assembly.
[Brief description of the drawings]
FIG. 1 is a plan view showing a configuration of a main part of a calendar display mechanism in a wristwatch according to an embodiment of the present invention.
FIG. 2 is a side sectional view showing a schematic configuration of a wristwatch according to the embodiment.
FIG. 3 is a cross-sectional view showing a main part of a calendar display mechanism in the same embodiment.
FIG. 4 is a plan view showing a configuration of a piezoelectric actuator that is a component of the calendar display mechanism in the embodiment.
FIG. 5 is a cross-sectional view showing a pressing adjustment cam included in the piezoelectric actuator in the same embodiment.
FIG. 6 is a cross-sectional view showing a diaphragm which is a component of the piezoelectric actuator in the same embodiment.
FIG. 7 is a diagram showing a schematic drive configuration when a voltage is applied to the piezoelectric element of the diaphragm in the same embodiment.
FIG. 8 is a diagram schematically illustrating a state in which the diaphragm according to the embodiment vibrates longitudinally.
FIG. 9 is a diagram schematically illustrating a state in which the diaphragm according to the embodiment undergoes flexural vibration.
FIG. 10 is a view for explaining the trajectory of the protrusion when the diaphragm is vibrated in the embodiment.
FIG. 11 is a diagram showing a configuration of a drive circuit that supplies a drive signal to the piezoelectric actuator in the embodiment.
12 is a plan view showing a positional relationship between the piezoelectric actuator and the rotor when a pressing force is applied in a direction parallel to the vibration direction of the diaphragm in the embodiment. FIG.
FIG. 13 is a plan view showing a positional relationship between the piezoelectric actuator and the rotor when a pressing force is applied in a direction orthogonal to the vibration direction of the diaphragm in the embodiment.
FIG. 14 is a plan view showing a positional relationship between the piezoelectric actuator and the rotor when a pressing force is applied in a direction toward the center point of the rotor in the embodiment.
FIG. 15 is a plan view showing the shape of a piezoelectric actuator in a modification of the embodiment.
FIG. 16 is a plan view showing the shape of a piezoelectric actuator in a modification of the embodiment.
FIG. 17 is a plan view showing a configuration of a piezoelectric actuator in a modification of the embodiment.
18 is a plan view showing a configuration of a piezoelectric actuator according to a modification of the embodiment. FIG.
FIG. 19 is a plan view showing a configuration of a piezoelectric actuator in a modification of the embodiment.
FIG. 20 is a schematic diagram showing a conventional example of a calendar display mechanism of a wristwatch including a piezoelectric actuator.
FIG. 21 is a schematic diagram showing a conventional piezoelectric actuator.
[Explanation of symbols]
10 ... Diaphragm (diaphragm),
11: Support member (support member),
11a ... one end,
11b ... the other end,
11c ... shaft part,
11d part,
11e ... guide,
11f, 11g ... shaft portion (fixing tool),
12 ... Spring member (pressing means),
12a ... one end (supporting member contact part),
12b ... shaft part (mounting part),
12c ... the other end (adjusting means contact portion),
12d ... shaft part,
13 ... Pressing adjustment cam (adjusting means, eccentric cam),
13a ... shaft part,
13b ... Terminal guide hole (adjustment means, adjustment hole),
13c: spacer,
13d ... Shaft shaft portion,
13e ... through hole,
13f ... adjustment terminal,
18 ... balance part,
30, 31 ... Piezoelectric element,
32 ... Reinforcing plate (reinforcing part),
33 ... electrodes,
36 ... projection (end),
100 ... rotor,
103 ... Ground plate (support),
500 ... Drive circuit,
A: Piezoelectric actuator.

Claims (5)

A long plate-like diaphragm formed by laminating a piezoelectric element and a reinforcing part, a support member that supports the diaphragm, and the diaphragm so that the end portion in the longitudinal direction of the diaphragm is in contact with the drive target wherein a pressing means for pressing in its plane direction, comprises an adjustment means for adjusting the pressing force by the pressing means, the vibration stretching and bending in the plane direction by supplying a driving signal to said piezoelectric element A piezoelectric actuator that is generated in a vibration plate and drives the drive object by displacement of the end portion accompanying the vibration ,
The pressing means includes an attachment portion attached to a predetermined support, an adjustment means contact portion that is displaced in the in-plane direction by the adjustment means while the adjustment means is in contact, and the adjustment means contact A piezoelectric actuator , comprising: a support member contact portion that presses the support member in the in-plane direction with a pressing force corresponding to a displacement amount of the portion . The attachment portion and the adjustment means contact portion of the pressing means are plate-like members arranged in parallel with the diaphragm, and the adjustment means contact portion is in contact with the adjustment means on a side surface thereof. Is displaced by the adjusting means in the state
The piezoelectric actuator according to claim 1 . The piezoelectric actuator according to claim 1 or 2 ,
A drive circuit for supplying the drive signal to the piezoelectric element;
A power supply for supplying power to the drive circuit;
A timepiece comprising a calendar display wheel driven by the piezoelectric actuator. The piezoelectric actuator according to claim 1 or 2 ,
A drive circuit for supplying the drive signal to the piezoelectric element;
A power supply for supplying power to the drive circuit;
A portable device comprising the driving object driven by the piezoelectric actuator. A long plate-like diaphragm formed by laminating a piezoelectric element and a reinforcing part, a support member that supports the diaphragm, and the diaphragm so that the longitudinal end of the diaphragm is in contact with the drive target A pressing unit that presses in the in-plane direction; and an adjusting unit that adjusts the pressing force of the pressing unit. The pressing unit abuts on the mounting unit attached to a predetermined support and the adjusting unit. The piezoelectric actuator includes an adjusting means abutting portion and a supporting member abutting portion that presses the supporting member in the in-plane direction with a pressing force according to a displacement amount of the adjusting means abutting portion. A method of adjusting,
Causing the diaphragm to expand and contract and bend in the in-plane direction by supplying a driving signal to the piezoelectric element, and driving the driving object by displacement of the end portion accompanying the vibration;
While measuring the drive efficiency of the drive target, the adjustment means is displaced in the in-plane direction by the adjustment means while the adjustment means is in contact with the adjustment means contact portion. Adjusting the pressing force by the support member abutting portion so as to increase efficiency; and
Adjustment method with.

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