JP4333146B2 - Piezoelectric actuators, watches and portable devices - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric actuator, a timepiece, and a portable device.
[0002]
[Prior art]
Since piezoelectric elements are excellent in conversion efficiency from electrical energy to mechanical energy and responsiveness, various piezoelectric actuators utilizing the piezoelectric effect of piezoelectric elements have been developed in recent years. This piezoelectric actuator is applied to fields such as a piezoelectric buzzer, an inkjet head of a printer, or an ultrasonic motor.
[0003]
FIG. 38 is a plan view schematically showing an ultrasonic motor using a conventional piezoelectric actuator. As shown in the figure, this type of ultrasonic motor is called a puff type, and the rotor surface is brought into contact with the tip of a vibrating piece coupled to a piezoelectric element with a slight inclination. Under such a configuration, when the piezoelectric element expands and contracts due to the alternating voltage from the oscillating unit and the vibrating piece reciprocates in the length direction, a component force is generated in the circumferential direction of the rotor, and the rotor rotates. ing.
[0004]
There is also known a technique that includes two ultrasonic vibrators (piezoelectric elements), vibrates each ultrasonic vibrator at its own electrical resonance frequency, and displaces the resonator element by this vibration (special feature). (Kaihei 10-225151).
[0005]
[Problems to be solved by the invention]
However, the displacement of the piezoelectric element is minute although it depends on the applied voltage, and is usually about several μm, and the same applies to the case of vibrating at the resonance frequency described above. For this reason, the displacement is amplified by some amplification mechanism and transmitted to the rotor. However, when an amplification mechanism is used, there is a problem that energy is consumed to move itself and efficiency is lowered. In addition, when the amplification mechanism is used, it may be difficult to stably transmit the driving force to the rotor.
[0006]
In addition, since a small portable device such as a wristwatch is driven by a battery, it is necessary to reduce power consumption and driving voltage. Therefore, when a piezoelectric actuator is incorporated in such a portable device, it is particularly required that the energy efficiency is high and the driving voltage is low.
[0007]
By the way, in a calendar display mechanism that displays days, days of the week, etc. in a watch or the like, the rotational driving force of an electromagnetic step motor is intermittently transmitted to a date wheel or the like via a wheel train, and the date wheel is In general, it is feed-driven. On the other hand, wristwatches are carried around a wrist by wrapping a belt around them. Therefore, there has been a long-standing demand for thinning for convenience of carrying. In order to reduce the thickness, it is also necessary to reduce the thickness of the calendar display mechanism. However, since the step motor is constructed by incorporating components such as a coil and a rotor in the out-of-plane direction, there is a limit to reducing the thickness thereof. For this reason, the conventional calendar mechanism using a step motor has a problem that it is structurally unsuitable for thinning.
[0008]
In particular, in order to make the mechanical system of movement (so-called movement) between a watch with a calendar display mechanism and a watch without such a mechanism, it is necessary to configure the calendar display mechanism on the dial side, In an electromagnetic step motor, it is difficult to reduce the thickness so that it can be configured on the dial side. Accordingly, the conventional timepiece needs to be manufactured by separately designing the mechanical system of the hand movement depending on the presence or absence of the display mechanism, which has been a problem in improving the productivity.
[0009]
The present invention has been made in consideration of the above circumstances, and is a piezoelectric actuator that transmits vibrations of a piezoelectric element efficiently, is suitable for downsizing and thinning, and can stably transmit a driving force. It is an object to provide a clock device and a portable device using the.
[0010]
In order to solve the above problems, a piezoelectric actuator according to the present invention includes a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing plate. , Provided with a protrusion at a position shifted from the center in the width direction at the end in the longitudinal direction A diaphragm, A plurality of electrodes disposed on the same surface of the piezoelectric element; Longitudinal vibration that causes the diaphragm to vibrate in the longitudinal direction within a plane to which the diaphragm belongs, and the diaphragm that is orthogonal to the longitudinal direction within the plane Direction of the vibrating body Select either flexural vibration that swings in the width direction Supply voltage to the electrode And the diaphragm is attached to the support. Please Above The protrusion is Drive target Rotor By switching the switch, When the longitudinal vibration is selected and the bending vibration is selected, the number of electrodes to which a voltage is supplied is changed to switch between the longitudinal vibration and the bending vibration of the vibrating body, Of the drive target Rotor of Drive Direction In reverse It is characterized by switching.
[0021]
A timepiece according to the present invention includes the piezoelectric actuator.
According to this configuration, since the built-in piezoelectric actuator has a structure suitable for thinning, the entire watch can be easily thinned. Further, since the built-in piezoelectric actuator is highly efficient, the energy consumption of the entire timepiece can be reduced.
[0022]
A portable device according to the present invention includes the piezoelectric actuator.
According to this configuration, since the built-in piezoelectric actuator is suitable for thinning, the entire device can be easily thinned, and the high-efficiency piezoelectric actuator is installed, so that the battery life is extended, and the portable device It is suitable as.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A. First embodiment
A-1. Watch calendar display mechanism
First, FIG. 1 is a view showing a calendar display mechanism of a wristwatch provided with a piezoelectric actuator according to the first embodiment of the present invention. As shown in the figure, this calendar display mechanism includes a piezoelectric actuator A1, a rotor 100, an intermediate wheel 101, and a ring-shaped date wheel 102 on which day and day are written.
[0024]
The rotor 100 supported by the main plate (support) 103 is rotationally driven in the direction indicated by the arrow Y in the figure by the piezoelectric actuator A1. An intermediate wheel 101 pivotally supported by the main plate 103 is engaged with the rotor 100, and a date wheel 102 is engaged with the intermediate wheel 101. With this configuration, the date wheel 102 is rotated in the direction indicated by the arrow Z in the figure as the rotor 100 driven by the piezoelectric actuator A1 rotates.
[0025]
Next, a configuration of a timepiece incorporating the calendar display mechanism described above will be described with reference to FIG. In the figure, the calendar display mechanism described above is incorporated in the shaded portion. A disk-shaped dial plate 201 is provided above the calendar display mechanism (shaded portion). A window portion 202 is provided in a part of the outer peripheral portion of the dial plate 201 to display the date so that the date written on the date indicator 102 can be seen from the window portion 202. A movement 204 for driving the hand movement 203 is provided below the dial 201. Under this configuration, when the date indicator 102 is rotated, the display of the day, day of the week, etc. displayed on the window 202 described above is switched.
[0026]
A-2. Configuration of piezoelectric actuator
Next, the piezoelectric actuator according to the present embodiment will be described with reference to FIGS. As shown in FIG. 3, the piezoelectric actuator A1 includes a long plate-like diaphragm 10 formed long in the left-right direction in the figure, and a support member 11 that supports the diaphragm 10 on a ground plate 103 (see FIG. 1). I have.
[0027]
A protruding portion 36 protrudes from the longitudinal end portion 35 of the diaphragm 10 toward the rotor 100, and the protruding portion 36 is in contact with the side surface of the rotor 100. 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 short-circuiting.
[0028]
One end portion (attachment portion) 37 of the support member 11 is attached to the rotor 100 side slightly from the center in the longitudinal direction of the diaphragm 10. The other end portion (fixed portion) 38 of the support member 11 is supported on the base plate 103 (see FIG. 1) by screws 39. Under this configuration, the support member 11 supports the diaphragm 10 in a state in which the diaphragm 10 is urged toward the rotor 100 by its elastic force, thereby causing the protrusion 36 of the diaphragm 10 to abut against the side surface of the rotor 100. It has been.
[0029]
As shown in FIG. 4, the diaphragm 10 has a laminated structure in which a reinforcing plate 32 made of stainless steel or the like having a smaller thickness than the piezoelectric elements 30 and 31 is disposed between the two piezoelectric elements 30 and 31. ing. By disposing the reinforcing plate 32 between the piezoelectric elements 30 and 31 in this way, damage to the diaphragm 10 due to overamplitude or external force of the diaphragm 10 can be reduced. Further, as the reinforcing plate 32, a member having a thickness smaller than that of the piezoelectric elements 30 and 31 is used so as not to disturb the vibration of the piezoelectric elements 30 and 31 as much as possible.
[0030]
Electrodes 33 are respectively disposed on the surfaces of the piezoelectric elements 30 and 31 disposed above and below. A voltage is supplied to the piezoelectric elements 30 and 31 through the electrode 33 from a conduction configuration described later. 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 ( (Pb (Zn1 / 3-Nb2 / 3) 03 1-x-Pb Ti 03 x) x varies depending on the composition. X = 0.09), lead scandium niobate ((Pb ((Sc1 / 2Nb1 / 2) 1- x Tix)) 03) x varies depending on the composition. Various types such as x = 0.09) can be used.
[0031]
When an alternating voltage is applied to the piezoelectric elements 30 and 31 from the drive circuit described later via the electrode 33, the diaphragm 10 vibrates as the piezoelectric elements 30 and 31 expand and contract. At that time, as shown in FIG. 5, the diaphragm 10 vibrates by longitudinal vibration that expands and contracts in the longitudinal direction, whereby the diaphragm 10 vibrates in the direction indicated by the arrow in FIG. No load state, that is, a state where the protrusion 36 is not in contact with the rotor 100). Further, as described above, the vibration plate 10 has a structure in which the long plate-like piezoelectric elements 30 and 31 are laminated, and is driven in parallel, whereby a larger displacement can be obtained with a low driving voltage.
[0032]
A-3. Operation of piezoelectric actuator
Next, the operation of the piezoelectric actuator A1 having the above configuration will be described. First, when a voltage is applied to the diaphragm 10 from a drive circuit (not shown), the piezoelectric elements 30 and 31 bend and vibrate due to the expansion and contraction of the piezoelectric elements 30 and 31, as shown in FIG. The diaphragm 10 vibrates in the direction of the arrow. The rotor 100 is rotated in the direction of the arrow in the drawing along with the protrusion 36 caused by this vibration. By rotating the rotor 100 in this way, the date indicator 102 is rotated via the intermediate wheel 101 (see FIG. 1), and the displayed day and day are switched.
[0033]
Here, in the piezoelectric actuator A1, since the protrusion 36 that is brought into contact with the rotor 100 is provided at a position shifted from the center line of the diaphragm 10 indicated by a one-dot chain line in the figure, the reaction force from the side surface of the rotor 100 As a result, bending vibration as shown in FIG. If the applied frequency, the shape of the diaphragm 10 and the position of the projection 36 are set so that the vibration frequency of the bending vibration and the longitudinal vibration generated by the expansion and contraction of the piezoelectric elements 30 and 31 substantially coincide, that is, resonate, the vibration The amplitude of vibration generated in the plate 10 is increased. Thus, if the longitudinal vibration caused by the expansion and contraction of the piezoelectric elements 30 and 31 and the bending vibration described above are resonated, the protrusion 36 moves along an elliptical orbit as shown in FIG. That is, if the bending vibration that resonates with the longitudinal vibration is excited, the protrusion 36 moves along a larger elliptical orbit. If the protrusion 36 moves along such a large elliptical orbit, the time for the protrusion 36 to contact the rotor 100 becomes longer, and the displacement of the protrusion 36 at the time of contact increases. Therefore, if a bending vibration that resonates with a longitudinal vibration due to expansion and contraction of the piezoelectric elements 30 and 31 is induced, a more efficient driving force can be transmitted.
[0034]
Further, in this piezoelectric actuator A1, since the protrusion 36 is biased toward the rotor 100 by the elastic force of the support member 11, sufficient friction can be obtained between the rotor 100 and the protrusion 36. Yes. As a result, slippage between the protrusion 36 and the rotor 100 is reduced, and stable driving force transmission from the protrusion 36 to the rotor 100 becomes possible. Furthermore, contact can be maintained even if there are dimensional errors or changes with time. In order to induce the bending vibration due to the reaction force from the rotor 100 described above, the contact portion of the diaphragm 10 with the rotor 100, that is, the protrusion 36 may be displaced from the center line of the diaphragm 10. The part 36 may be provided at a position other than the position shown in the figure.
[0035]
Further, in the piezoelectric actuator A1 according to the present embodiment, the end portion 37 of the support member 11 is attached to a position where the amplitude of the center line of the diaphragm 10 indicated by a broken line in FIG. ing. Specifically, the diaphragm 10 is attached to the rotor 100 side with respect to the central portion in the longitudinal direction. When the diaphragm 10 is rectangular as described above, the center portion in the longitudinal direction of the diaphragm 10 becomes a node of vibration when no load is applied. However, as described above, the diaphragm 10 is affected by the reaction force from the rotor 100 and the like. In fact, as shown in FIG. 8, the vibration node is located closer to the rotor 100 than the central portion. By supporting the diaphragm 10 at a position that becomes a vibration node in this way, loss of vibration energy is reduced, and more efficient driving force transmission is possible. Further, if the position of the vibration node of the support member 11 accompanying the vibration of the diaphragm 10 is made to substantially coincide with the end portion 37 of the support member 11, the loss of vibration energy can be further reduced.
[0036]
Further, in the piezoelectric actuator A1 according to the present embodiment, the vibration plate 10 having a structure in which the piezoelectric elements 30 and 31 and the reinforcing plate 32 are stacked can rotationally drive the rotor 100 without an amplification member. Becomes simple, and the size of the apparatus can be easily reduced. Further, the mechanical components of the piezoelectric actuator A1 are only the diaphragm 10 and the support member 11, and no components are stacked in the thickness direction (the direction perpendicular to the paper surface of FIG. 1), so that the thickness can be easily reduced. is there.
[0037]
In addition, the piezoelectric actuator A1 is configured to drive the rotor 100 only in the direction indicated by the arrow in the drawing, and another diaphragm for driving the rotor 100 in the reverse direction, or the contact direction of the diaphragm to the rotor 100 In other words, there is no mechanism for changing the frequency, i.e., there are few elements that prevent the vibration of the diaphragm 10, so that the driving force can be transmitted more efficiently.
[0038]
In addition, since the piezoelectric actuator A1 according to the present embodiment is configured to drive the rotor 100 in only one direction, it is necessary to regulate the rotation of the rotor 100 in the reverse direction. However, the rotor 100 rotates in reverse by an external force or the like. There are times to try. For example, when a reverse rotational force exceeding the frictional force between the protrusion 36 and the rotor 100 is generated, both slip and allow the rotor 100 to reversely rotate. However, in the piezoelectric actuator A1 according to the present embodiment, as shown in FIG. 9, the support member 11 has elasticity instead of a rigid body. Along with the rotation, the vibration plate 10 is allowed to rotate in a state where the protrusion 36 is in contact with the rotor 100. And the diaphragm 10 returns to the lower position shown with a dashed-dotted line in a figure with the elastic force of the supporting member 11. FIG. At this time, since the protrusion 36 and the rotor 100 are in contact with each other, the rotor 100 also returns in the forward direction in accordance with the return of the diaphragm 10. Therefore, the reverse rotation of the rotor 100 can be restricted. Here, as shown in FIG. 10, in the present embodiment, the rotation center of the diaphragm 10 is a line B extending from a contact point A between the rotor 100 and the protrusion 36 in a direction opposite to the driving direction of the rotor 100 at the point A. The center of rotation is set in a quadrant formed by a line C orthogonal to the line B at the point A. Specifically, the end portion 38 of the support member 11 belonging to the quadrant described above is arranged. The diaphragm 10 is allowed to rotate as a center. By providing the rotation center at such a position, as described above, the rotation and return operations are performed by the diaphragm 10, and the reverse rotation of the rotor 100 can be suppressed.
[0039]
Further, when the piezoelectric actuator A1 is applied to the calendar display mechanism as described above, the piezoelectric actuator A1 itself can be easily reduced in size, so that the size of the entire calendar display mechanism is not increased. It is also possible to increase the diameter. Therefore, the rotational torque of the rotor 100 obtained from the piezoelectric actuator A1 can be increased without increasing the voltage applied to the piezoelectric elements 30 and 31.
[0040]
A-4. Modification of piezoelectric actuator
The piezoelectric actuator according to the present invention is not limited to the above-described embodiment, and various modifications as described below are possible.
[0041]
A-4-1. First modification
In the piezoelectric actuator A1 shown in the above-described embodiment, the protrusion 36 is provided at the contact portion of the diaphragm 10 with the rotor 100. However, as shown in FIG. 11, the rotor 100 of the rectangular diaphragm 10 is provided. A notch 90 having a notch on the side may be formed, and the notch 90 may be brought into contact with the side surface of the rotor 100. Also in this case, it is easy to manage the surface state of the notch 90 as in the case of the protrusion 36 described above.
[0042]
A-4-2. Second modification
In the above-described embodiment, the electrode 33 is provided on the entire surface of the piezoelectric elements 30 and 31, but the electrode 33 is disposed only near the center of the piezoelectric elements 30 and 31 as shown in FIG. The electrodes 33 may not be disposed on both end sides. That is, the piezoelectric elements 30 and 31 may be configured to have an electrode portion having an electrode on its surface and an electrodeless portion positioned on both ends thereof. In this way, it is possible to reduce the driving voltage while maintaining the driving force to the rotor 100. This is because when the diaphragm 10 is vibrated at its natural vibration frequency, the displacement at both ends of the diaphragm 10 due to the vibration is sufficiently large, and a voltage is applied to that portion to expand and contract the piezoelectric elements 30 and 31 on both ends. This is because the displacement does not increase further.
[0043]
A-4-3. Third modification
In the above-described embodiment, the rectangular diaphragm 10 is used. However, as shown in FIG. 13, a tapered diaphragm 95 with a narrower rotor 100 side may be used. When the diaphragm 95 having such a shape is manufactured, a tapered piezoelectric element and a reinforcing plate may be laminated similarly to the diaphragm 10 described above. When such a diaphragm 95 is used, the displacement of the end portion 96 on the rotor 100 side of the diaphragm 10 is increased, and the transmission efficiency of the driving force is improved. In addition, since the length in the width direction, which is the vertical direction in the figure, is not uniform, resonance in the width direction of the diaphragm 10 can be suppressed, that is, the vibration in the width direction can be reduced.
[0044]
A-4-4. Fourth modification
Further, as shown in FIG. 14, a horn part (extension part) 110 extending from the diaphragm 10 toward the rotor 100 may be provided. When such a horn part 110 is provided, as shown in FIG. 15, the reinforcing plate 32 is formed in a shape including the horn part 110 as shown in the figure, and piezoelectric elements 30 and 31 are laminated on the upper and lower sides thereof, respectively. You just have to do it. If the diaphragm 10 is vibrated under this configuration, the diaphragm 10 and the horn unit 110 vibrate with an amplitude as indicated by a broken line in FIG. Accordingly, the displacement of the tip of the horn part 110 that comes into contact with the rotor 100 is increased, and the driving force can be applied efficiently. The horn part 110 is not limited to the shape as shown in FIG. 14, but may have a shape as shown in FIG.
[0045]
A-4-5. Fifth modification
Further, as shown in FIG. 17, a tangent line between the protrusion 36 of the diaphragm 10 and the rotor 100, that is, a line S perpendicular to the direction of the pressing force F from the protrusion 36 to the rotor 100 in the initial vibration state, that is, the rotor. The end portion 38 of the support member 11, that is, the portion fixed to the base plate 103 may be substantially positioned on the drive direction line at the contact point between the protrusion 100 and the protrusion 36. If the diaphragm 10, the support member 11, and the rotor 100 are arranged so as to have such a positional relationship, in order to adjust the pressing force or the like of the protrusion 36 against the rotor 100, the end 38 fixed with the screw 39. Even when the positions of the support member 11 and the diaphragm 10 are finely adjusted around the center, the contact position and angle between the rotor 100 and the protrusion 36 do not change, and a stable driving force can always be applied. . In addition, it is possible to prevent a change in the contact angle between the diaphragm and the rotor due to a shape, a positional deviation, and a change with time.
[0046]
A-4-6. Sixth modification
In addition, as shown in FIG. 18, the two support members 11 may support both ends in the longitudinal direction of the diaphragm 10. By doing so, it is possible to suppress vibration in the width direction (vertical direction in the figure) of the diaphragm 10, that is, vibration that hinders vibration in the horizontal direction in the figure that is necessary for driving the rotor 100. . In this case, as shown in FIG. 19, the end portion 37 of the support member 11 substantially coincides with the position of the vibration of the support member 11 accompanying the vibration of the diaphragm 10. For example, the length of the support member 11 is set to the length of the support member 11. If the length becomes ¼ of the vibration wavelength, the obstruction of the vibration of the diaphragm 10 in the horizontal direction in the figure is reduced, and the efficiency is further improved.
[0047]
In addition, when the diaphragm 10 is supported by the two support members 11 as described above, as shown in FIG. 20, one of the support members 11 supports a position serving as a vibration node of the diaphragm 10, and the other one. The support member 11 may support the end portion of the diaphragm 10 on the rotor 100 side. In this way, since one support member 11 supports the vibration node, the loss of vibration energy is reduced, and the other support member 11 is in the width direction in the vicinity of the contact portion with the rotor 100. Can be suppressed.
[0048]
A-4-7. Seventh modification
In the above-described embodiment, the support member 11 biases the diaphragm 10 toward the rotor 100. However, as shown in FIG. 21, a spring member (elastic member) 180 is provided to displace the diaphragm 10. You may make it urge to the rotor 100 side. As shown in the figure, a support member 11 is attached to the upper side of the diaphragm 10, and one end of a spring member 180 is attached to the lower side of the diaphragm 10. The other end of the spring member 180 is supported by a pin 181 erected on the main plate 103 (see FIG. 1). As a result, the diaphragm 10 is urged toward the rotor 100, which is the upper side of the drawing, so that the protrusion 36 is brought into contact with the side surface of the rotor 100. If the spring member 180 is provided in this manner to urge the diaphragm 10 toward the rotor 100, a stable driving force can be transmitted as in the piezoelectric actuator A1 of the above-described embodiment.
[0049]
Even when the support member 11 that supports the diaphragm 10 and the spring member 180 that urges the diaphragm 10 toward the rotor 100 are provided in this manner, as shown in FIG. The diaphragm 10 may be rotated around the position of the end 38 in the quadrant formed by the line C, for example, as shown in the figure. In this way, even when the rotor 100 attempts to reversely rotate due to an external force, the diaphragm 10 is rotated after the diaphragm 10 is rotated along with the reverse rotation of the rotor 100 as shown in FIG. By returning to the position, the rotor 100 returns to the forward direction with the return of the diaphragm 10, and the reverse rotation of the rotor 100 can be suppressed.
[0050]
Even when the support member 11 and the spring member 180 are provided in this way, the diaphragm 10 may be formed in a tapered shape as shown in FIG. 24, or a horn portion (see FIG. 14) is provided. You may do it.
[0051]
A-4-8. Eighth modification
In the above-described embodiment, the diaphragm 10 has a structure in which the piezoelectric elements 30 and 31 are stacked on the upper and lower sides of the reinforcing plate 32. However, the present invention is not limited to this, and the upper and lower sides of one piezoelectric element 251 are reinforced. The plates 32 may be laminated. In this case, as shown in FIG. 25, the upper reinforcing plate 32 is supported by the support member 11a, the lower reinforcing plate 32 is supported by the support member 11b, and the reinforcing plate 32 and the support members 11a and 11b are electrically conductive. What is necessary is just to form with a body. Under this configuration, a drive voltage may be supplied from the drive circuit 250 to the piezoelectric element 251 through the support members 11 a and 11 b and the reinforcing plate 32. In this way, the support members 11a and 11b have a conduction function of supplying a drive voltage to the piezoelectric element 251 in addition to the function of supporting the diaphragm 10 while urging the diaphragm 10 toward the rotor 100 side. Accordingly, it is not necessary to separately provide a conduction structure for supplying a driving voltage to the piezoelectric element 251 and the structure is simplified. Further, there is no need for a conductive component that hinders vibration of the diaphragm 10, and efficient driving force transmission can be performed.
[0052]
A-4-9. Ninth modification
Further, as shown in FIGS. 26 and 27, also when using the diaphragm 10 in which the reinforcing plate 32 and the piezoelectric elements 30 and 31 are respectively stacked above and below the reinforcing plate 32, the support members 11c and 11d formed of a conductor are used. Thus, a drive voltage may be supplied from the drive circuit 250 to the piezoelectric elements 30 and 31.
[0053]
The support member 11c has a shape that branches into two on the vibration plate 10 side, and branches into an upper end portion 260 that branches to the upper side (front side in FIG. 26) and a lower side (the back side in the drawing). A lower end 261 is provided. The upper end 260 is attached to the electrode 33 formed on the surface of the piezoelectric element 30 by solder, a conductive adhesive or the like, and the lower end 261 is soldered to the electrode 33 formed on the surface of the piezoelectric element 31. Or a conductive adhesive. On the other hand, the support member 11 d is attached to the reinforcing plate 32, whereby a drive voltage is supplied from the drive circuit 250 to the piezoelectric elements 30 and 31. Also in this case, as described above, the support members 11c and 11d have a function of supporting the diaphragm 10, and also have a function of conducting to the piezoelectric elements 30 and 31, which simplifies the configuration and improves efficiency. Good driving force can be transmitted.
[0054]
A-5. Conduction configuration to piezoelectric actuator
Next, a conduction configuration for supplying a drive voltage from the drive circuit to the piezoelectric elements of the piezoelectric actuators of the various modes described above will be described. As described in the eighth and ninth modifications, the drive voltage may be supplied from the drive circuit to the piezoelectric element via the support member formed of a conductor, as shown in FIG. A driving voltage may be supplied to the piezoelectric element with a simple conduction configuration. As shown in the figure, in this conducting configuration, the upper and lower surfaces (electrodes 33) of the diaphragm 10 are sandwiched by a C-shaped elastic conducting member 280, and wiring is connected from the reinforcing plate 32 to the drive circuit 250. If such an elastic conducting member 280 is used, a driving voltage can be supplied from the driving circuit 250 to the piezoelectric elements 30 and 31 stacked one above the other with a simple configuration.
[0055]
29 and 30, a conducting wire 290 may be wound around the diaphragm 10, and a driving voltage may be supplied from the driving circuit 250 to the piezoelectric elements 30 and 31 via the wound conducting wire 290. . Even in this case, the drive voltage can be supplied to the piezoelectric elements 30 and 31 with a simple conduction configuration. As described above, when voltage is supplied via the elastic conductive member 280 or the conductive wire 290, the laminated structure of the diaphragm 10 may be a structure in which electrodes are arranged on the upper and lower surfaces, or a conductor on the upper and lower surfaces. It may have a structure in which such a reinforcing plate is arranged. In addition to the diaphragm having the laminated structure of the piezoelectric element and the reinforcing plate, the elastic conductive member 280 and the conductive wire 290 described above can also be used when a voltage is supplied to the piezoelectric element.
[0056]
B. Second embodiment
Next, a piezoelectric actuator according to a second embodiment of the present invention will be described. As shown in FIG. 31, the piezoelectric actuator according to the second embodiment has a configuration including a diaphragm 310 instead of the diaphragm 10 of the piezoelectric actuator A1 according to the first embodiment.
[0057]
As shown in FIG. 32, the diaphragm 310 has a structure in which the piezoelectric elements 30 and 31 are stacked on the upper and lower sides of the reinforcing plate 32 in the same manner as the diaphragm 10 in the first embodiment. However, as shown in FIG. This is different from the diaphragm 10 in that electrodes 33a, 33b, 33c, and 33d are disposed on the elements 30 and 31. As shown in the figure, in the diaphragm 310, the piezoelectric element 30 (not shown but the piezoelectric element 31 is the same) is divided into four regions, and electrodes 33a, 33b, 33c, and 33d are provided on the divided regions, respectively. It is arranged.
[0058]
A conduction configuration for supplying a drive voltage to the electrodes 33a, 33b, 33c, and 33d arranged on the four regions of the piezoelectric element 30 will be described with reference to FIG. As shown in the figure, by switching on / off a switch (selection means) 341, a mode in which a drive voltage is supplied from the power source 340 to all the electrodes 33a, 33b, 33c, 33d, and from the power source 340 to the electrodes 33a, The mode supplied to 33d can be switched.
[0059]
Here, when the switch 341 is turned on and the mode for supplying the driving voltage to all the electrodes 33a, 33b, 33c, and 33d is selected, as shown in FIG. Similar to the embodiment, the diaphragm 310 expands and contracts in the longitudinal direction and longitudinally vibrates in the longitudinal direction of the diaphragm 310 (hereinafter referred to as longitudinal vibration mode). On the other hand, when the switch 341 is turned off and the mode for supplying the driving voltage only to the electrodes 33a and 33d is selected, the piezoelectric element only in the region to which the driving voltage is applied expands and contracts, as shown in FIG. As shown, the diaphragm 310 is configured to flexurally vibrate in the width direction (vertical direction in the figure) within the plane to which the diaphragm 310 belongs (hereinafter referred to as a flexural vibration mode). Thus, the vibration mode of the diaphragm 310 can be selected by switching the switch 341.
[0060]
In the piezoelectric actuator according to the second embodiment, the rotor 100 is driven using the vibration plate 310 capable of switching between two vibration modes as described above, and the driving direction of the rotor 100 is changed by switching the vibration modes. It can be switched. When the longitudinal vibration mode is selected, as shown in FIG. 36, a driving force in the right direction in the drawing is applied from the contact portion between the rotor 100 and the protrusion 36 due to the longitudinal vibration of the diaphragm 310. The rotor 100 is rotated counterclockwise in the drawing.
[0061]
On the other hand, when the bending vibration mode is selected, as shown in FIG. 37, the bending vibration of the diaphragm 310 causes an upward driving force in the drawing to be applied from the contact portion between the rotor 100 and the protrusion 36. The rotor 100 can be rotated clockwise in the figure.
[0062]
In the piezoelectric actuator according to the second embodiment, the rotor 100 can be driven in the forward direction and the reverse direction by switching the switch 341. As described above, since the driving direction is switched by switching the vibration mode of the diaphragm 310, a diaphragm is provided for each driving direction, or the positional relationship between the diaphragm and the rotor to be driven is adjusted. There is no need to provide an adjusting mechanism. Therefore, the driving direction can be switched between forward and reverse without complicating the configuration and increasing the size of the apparatus.
[0063]
Note that the piezoelectric actuator according to the second embodiment can be variously modified similarly to the first embodiment described above. For example, the diaphragm 310 may be provided with a notch instead of the protrusion 36 (see FIG. 11). Further, the end 38 of the support member 11 may be positioned on the tangent line between the protrusion 36 of the vibration plate 310 and the rotor 100 (see FIG. 17). Further, a spring member may be provided in addition to the support member 11, and the diaphragm 310 may be urged toward the rotor 100 by the spring member (see FIG. 21).
[0064]
C. Modified example
In the various embodiments described above, the piezoelectric actuator is configured to rotationally drive the disk-shaped rotor. However, the driving target is not limited to this, and for example, the above-described member is a substantially rectangular parallelepiped member. You may make it contact | abut a diaphragm and drive this rectangular parallelepiped member to the longitudinal direction.
[0065]
The piezoelectric actuators according to the various embodiments described above can be mounted on a portable device other than a battery-driven timepiece, in addition to being mounted on a calendar display mechanism of a timepiece.
[0066]
【The invention's effect】
As described above, according to the present invention, the vibration of the piezoelectric element in the piezoelectric actuator can be efficiently transmitted, suitable for downsizing and thinning, and the driving force can be stably transmitted.
[Brief description of the drawings]
FIG. 1 is a plan view showing a calendar display mechanism of a timepiece provided with a piezoelectric actuator according to a first embodiment of the present invention.
FIG. 2 is a side sectional view showing a schematic configuration of a timepiece incorporating the calendar display mechanism.
FIG. 3 is a plan view showing an overall configuration of the piezoelectric actuator.
FIG. 4 is a side sectional view showing a diaphragm that is a component of the piezoelectric actuator.
FIG. 5 is a diagram illustrating a state in which the diaphragm vibrates longitudinally.
FIG. 6 is a diagram illustrating a state in which bending vibration is caused by a reaction force from a rotor of the calendar display mechanism when the vibration plate vibrates.
FIG. 7 is a diagram for explaining a trajectory of a protrusion provided on the diaphragm during the bending vibration.
FIG. 8 is a diagram for explaining an amplitude during vibration of the diaphragm;
FIG. 9 is a diagram for explaining a state of the diaphragm when the rotor is about to rotate backward.
FIG. 10 is a view for explaining a position of a rotation center that rotatably supports the diaphragm.
FIG. 11 is a plan view showing a first modification of the piezoelectric actuator.
FIG. 12 is a side sectional view showing a diaphragm in a second modification of the piezoelectric actuator.
FIG. 13 is a plan view showing a third modification of the piezoelectric actuator.
FIG. 14 is a plan view showing a fourth modification of the piezoelectric actuator.
FIG. 15 is a view for explaining a method of manufacturing a diaphragm according to a fourth modification of the piezoelectric actuator.
FIG. 16 is a diagram showing another modification of the fourth modification of the piezoelectric actuator.
FIG. 17 is a plan view showing a fifth modification of the piezoelectric actuator.
FIG. 18 is a plan view showing a sixth modification of the piezoelectric actuator.
FIG. 19 is a diagram for explaining the amplitude of a support member that is a component of a sixth modification of the piezoelectric actuator.
FIG. 20 is a plan view showing another example of the sixth modified example of the piezoelectric actuator.
FIG. 21 is a plan view showing a seventh modification of the piezoelectric actuator.
FIG. 22 is a view for explaining the position of a rotation center that rotatably supports a diaphragm that is a component of a seventh modification of the piezoelectric actuator.
FIG. 23 is a diagram for explaining a state of the diaphragm of the diaphragm when the rotor is about to rotate in the seventh modification.
FIG. 24 is a plan view showing another example of the seventh modified example of the piezoelectric actuator.
FIG. 25 is a diagram showing an eighth modification of the piezoelectric actuator.
FIG. 26 is a plan view showing a ninth modification of the piezoelectric actuator.
FIG. 27 is a side view showing a ninth modification of the piezoelectric actuator.
FIG. 28 is a diagram showing a conduction configuration for supplying a driving voltage to the piezoelectric actuator.
FIG. 29 is a plan view showing another example of a conduction configuration for supplying a driving voltage to the piezoelectric actuator.
FIG. 30 is a side view showing another example of a conduction configuration for supplying a driving voltage to the piezoelectric actuator.
FIG. 31 is a plan view showing an overall configuration of a piezoelectric actuator according to a second embodiment of the present invention.
FIG. 32 is a side view showing a diaphragm that is a component of the piezoelectric actuator according to the second embodiment.
FIG. 33 is a plan view showing the diaphragm of the piezoelectric actuator according to the second embodiment.
FIG. 34 is a diagram showing a conduction configuration for supplying a drive voltage to the piezoelectric actuator according to the second embodiment.
FIG. 35A is a diagram showing a state in which the diaphragm of the piezoelectric actuator according to the second embodiment vibrates longitudinally, and FIG. 35B is a diagram showing a state in which the diaphragm is flexibly vibrated.
FIG. 36 is a view for explaining the drive direction of the rotor when the diaphragm of the piezoelectric actuator according to the second embodiment vibrates longitudinally.
FIG. 37 is a view for explaining the driving direction of the rotor when the diaphragm of the piezoelectric actuator according to the second embodiment undergoes flexural vibration.
FIG. 38 is a plan view schematically showing an ultrasonic motor using a conventional piezoelectric actuator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Diaphragm, 11 ... Support member, 11a, 11b, 11c, 11d ... Support member, 30 ... Piezoelectric element, 31 ... Piezoelectric element, 32 ... Reinforcing plate, 33 ... Electrode, 35 ... End portion 36... Projection portion 37. End portion (mounting portion) 38. End portion (fixed portion) 90. Notch portion 95. Diaphragm 96. End portion 100. ... rotor, 101 ... intermediate wheel, 102 ... date wheel, 103 ... ground plate (support), 110 ... horn part (extension part), 180 ... spring member (elastic member), 250 ... drive circuit 251: Piezoelectric element, 280: Elastic conducting member, 290: Conductor, 310: Diaphragm, 340: Power supply, 341: Switch (selection means)

Claims (3)

A support;
A plate-like piezoelectric element having a longitudinal direction and a reinforcing plate are laminated, and a diaphragm having a protrusion at a position shifted from the center in the width direction at an end in the longitudinal direction ;
A plurality of electrodes disposed on the same surface of the piezoelectric element;
Longitudinal vibration that causes the diaphragm to vibrate in the longitudinal direction within the plane to which the diaphragm belongs, and bending that causes the diaphragm to swing in the width direction of the vibrator that is perpendicular to the longitudinal direction within the plane. select one of the vibration, and a switch for supplying a voltage to the electrode,
The diaphragm is the protrusion mounting et al is in the support have been in contact with the rotor to be driven,
By switching the switch, the longitudinal vibration and the bending vibration of the vibrating body are switched by changing the number of electrodes to which a voltage is supplied when the longitudinal vibration is selected and when the bending vibration is selected. The piezoelectric actuator is characterized in that the driving direction of the rotor to be driven is switched between forward and reverse .   A timepiece comprising the piezoelectric actuator according to claim 1.   A portable device comprising the piezoelectric actuator according to claim 1.

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