JP5245358B2 - Piezoelectric vibrator, piezoelectric actuator, and portable device - Google Patents

Description

  The present invention relates to a piezoelectric vibrator, a piezoelectric actuator, and a portable device.

2. Description of the Related Art Conventionally, electronic devices that are small and portable, such as wristwatches, have been demanded to reduce power consumption in order to extend battery life as well as to reduce the size and thickness of mounted components. Therefore, a piezoelectric actuator that is small and thin and has excellent conversion efficiency from electrical energy to mechanical energy is used instead of a step motor as a drive device incorporated in a timepiece (for example, Patent Documents 1 to 5). ).
As shown in Patent Document 1, a piezoelectric actuator incorporated in such a portable device includes a piezoelectric vibrating body having a substantially rectangular plate shape, in which a reinforcing plate is laminated on a rectangular piezoelectric element, Due to the piezoelectric lateral effect when an electric field is applied in the thickness direction of the element, the vibration of the piezoelectric vibrating body that vibrates in a direction (in-plane direction) along a plane orthogonal to the direction of the applied electric field is driven by a driven body such as a rotor. To drive to drive.
Here, in this specification, the plane direction orthogonal to the direction of the electric field applied to the piezoelectric element is referred to as “in-plane direction”. This in-plane direction is a set of a plurality of directions orthogonal to the direction of the electric field applied to the piezoelectric element. The piezoelectric vibrating body in the present invention vibrates along this in-plane direction. In the present specification, a direction intersecting the in-plane direction (a direction deviating from the in-plane direction) is referred to as an “out-of-plane direction”.

  Here, in the piezoelectric vibrating body in Patent Document 1, the shape of the reinforcing plate laminated on the piezoelectric element is provided in the vicinity of the plane center of the piezoelectric element, and is fixed to a support member or the like on the device side, and the piezoelectric element It has the shape which has a pair of movable part provided along each short side, respectively, and a pair of arm part which each connects a fixed part to each movable part. Each movable part is provided with a protrusion, and one of these protrusions is in contact with the rotor (driven body). The reason why the reinforcing plate has such a shape is, as described in Patent Document 1, is stabilization of flexural vibration and amplitude expansion which are difficult to control. In Patent Document 1, the area of the reinforcing plate is made smaller than the area of the piezoelectric element and the rigidity of the reinforcing plate is reduced while leaving the part necessary for fixing to the device and the part necessary for contact with the driven body. doing.

On the other hand, in Patent Document 2, the rigidity of the reinforcing plate is reduced by forming an opening in the reinforcing plate so as to be easily bent, or by reducing the thickness of the reinforcing plate in some places. In the plate, the slit is formed so that the bending rigidity in the width direction is higher than the bending rigidity in the longitudinal direction, thereby reducing the rigidity of the reinforcing plate. Similarly, in patent document 4, the rigidity of a reinforcement board is made low by forming a reinforcement board small so that it may contact only a part of piezoelectric element.
In Patent Document 5, the rigidity of the reinforcing plate is lowered by forming the reinforcing plate with a material having good bendability.

Japanese Patent No. 3832260 (FIG. 6, paragraphs 0008 and 0009) JP-A-8-114408 (FIG. 7) JP-A-6-104503 (FIG. 1) JP 2004-254417 A (FIGS. 2 and 7) International Publication No. 96/14687 pamphlet (14 pages 15 lines to 24 lines, FIG. 16)

  In recent years, there has been a demand for further downsizing and thinning of electronic devices. Further, by expanding the use of piezoelectric actuators, a driven body with a higher load can be driven or a driven body can be driven continuously. There is also a need to increase the driving speed. For this reason, it is required to further increase the driving efficiency by increasing the amplitude of the piezoelectric vibrating body. Here, the downsizing / thinning of the device and the increase in the amplitude of the piezoelectric vibrating body are inherently contradictory requirements. When the power source (battery) is downsized, the applied voltage becomes smaller and the amplitude becomes smaller, resulting in desired drive characteristics. On the other hand, when the applied voltage is increased to increase the amplitude, the power supply is increased in size. In addition, as the power source is reduced in size and the applied voltage is decreased, the displacement amount of the piezoelectric element is decreased, the driving efficiency with respect to the input power is reduced, and even the driven body cannot be driven. For these reasons, it is necessary to greatly improve the driving efficiency.

  As in Patent Documents 1 to 4, the rigidity of the reinforcing plate is lowered by making the area of the reinforcing plate smaller than that of the piezoelectric element, or the material of the reinforcing plate itself is made flexible as in Patent Document 5. Simply reducing the rigidity as a good material cannot be said to reliably increase the amplitude, and it was far from realizing the required drive efficiency. This is because the relationship between the rigidity of the reinforcing plate and the vibration energy density in each part of the piezoelectric vibrating body in a predetermined vibration mode has not been considered. Unless the significance of each type of reinforcing plate with low rigidity is clarified, the amplitude cannot be reliably increased in a predetermined vibration mode, and high driving efficiency cannot be obtained.

  In Patent Documents 1 to 4, the shape of the reinforcing plate is changed to lower the rigidity of the reinforcing plate. Table 1 shows the contact state between the piezoelectric element and the reinforcing plate in each of the vibration nodes and antinodes in Patent Documents 1 to 4.

  In Patent Documents 1 to 4, since the reinforcing plate and the piezoelectric element are in contact with each other at the node of the longitudinal vibration where the distortion of the longitudinal vibration is the largest, the vibration of the piezoelectric vibrating body is hindered and the vibration efficiency is lowered. Further, in Patent Documents 2 and 3, since the reinforcing plate and the piezoelectric element are in contact with each other at the antinode of the bending vibration where the distortion of the bending vibration becomes large, the vibration of the piezoelectric vibrating body is hindered and the vibration efficiency is lowered. In Patent Document 2, since there is no reinforcing plate, the electrode has been described as having a role of a reinforcing plate. Further, in Patent Document 4, a reinforcing plate is present at the center portion in the width direction at the node of longitudinal vibration, and the reinforcing plate and the piezoelectric element are in contact with each other at this portion.

  In Patent Documents 1 and 4, the reinforcing plate and the piezoelectric element do not contact at the antinode of bending vibration, but the portion of the reinforcing plate extending substantially along the longitudinal direction at the substantially central portion in the width direction of the rectangular piezoelectric element. The shape of the arm portion (referred to as an arm portion in Patent Document 1) is not particularly considered, and since the width of the portion is thin, the direction along the plane perpendicular to the direction of the electric field applied to the piezoelectric element (in-plane direction) ) May not be restricted by the reinforcing plate. As a result, there is a possibility that the effect of amplitude expansion cannot be obtained. That is, simply reducing the rigidity of the reinforcing plate causes displacement in a direction (out-of-plane direction) other than a direction along the plane (in-plane direction) perpendicular to the direction of the electric field applied to the piezoelectric element. The amplitude of vibration in the direction along the plane orthogonal to the direction (in-plane direction) is diminished.

Here, in substantially the same manner as the reinforcing plates in Patent Documents 1 and 4, in the piezoelectric vibrating body 100 (FIG. 33) having the reinforcing plate (FIG. 32) having an area considerably smaller than the area of the piezoelectric element, other than the in-plane direction. FIG. 34 and FIG. 35 show the analysis of the tendency of displacement in the direction (out-of-plane direction).
The reinforcing plate 101 used here has a rectangular outer shape (two-dot chain line) as shown in FIG. 32, and the regions of the reinforcing plate 101 divided into four equal parts in length and width are each greatly hollowed out (recessed portion 101A). ). A piezoelectric vibrating body 100 in FIG. 33 includes the reinforcing plate 101 and piezoelectric elements 102 that are bonded to both the front and back surfaces of the reinforcing plate 101. Here, a non-contact portion 103 where the reinforcement plate 101 and the piezoelectric element 102 are not in contact is formed in a region where the cut-through portion 101A (FIG. 32) is formed in the reinforcement plate 101. Are formed at positions corresponding to the punched-through portions 101A.
In the piezoelectric element 102, five electrodes similar to the electrodes 231 to 235 divided into five as shown in FIG. 3 are formed. 34, a voltage is applied to the electrodes corresponding to the electrodes 232, 233, and 234 of FIG. 3 in each piezoelectric element 102 of the piezoelectric vibrating body 100, and a voltage is applied to the electrodes corresponding to the electrodes 231 and 235 of FIG. The state which vibrated the piezoelectric vibrating body 100 was shown. Thus, by not applying a voltage to a part of the electrodes in the piezoelectric element 102, the expansion and contraction state in the direction along the longitudinal direction of the piezoelectric element 102 becomes unbalanced, and thereby in a direction orthogonal to the longitudinal direction of the piezoelectric element 102. Bending vibration is induced. FIG. 34 shows a state in which the piezoelectric vibrating body 100 is vibrated with no load without bringing the rotor or the like into contact with the piezoelectric vibrating body 100.

  FIG. 34 shows the result of simulation of the vibration state of the piezoelectric vibrating body of FIG. 33 by software. FIG. 35 is a diagram showing only the piezoelectric element 102 in the piezoelectric vibrating body 100 during vibration in FIG. In FIGS. 34 and 35, the displacement of the piezoelectric element 102 and the reinforcing plate 101 is exaggerated from the actual one. From FIGS. 34 and 35, however, the reinforcing plate 101 and the piezoelectric element 102 are in contact with each other. It can be seen that the vibration in the Z-axis direction in the non-contact portion 103 (FIG. 34) that is not large is larger than the portion where the reinforcing plate 101 and the piezoelectric element 102 are in contact. As described above, when the cut-out portion is unnecessarily large, displacement in a direction other than the in-plane direction (out-of-plane direction) occurs.

  In view of the above, an object of the present invention is to provide a piezoelectric vibrating body, a piezoelectric actuator, and a piezoelectric actuator that can greatly improve driving efficiency by examining the shape of the reinforcing plate and the vibration energy density at each part of the reinforcing plate from various viewpoints. And to provide a portable device.

Pressure electrostatic vibrator of the present invention includes a piezoelectric element, and a reinforcing plate which the piezoelectric element is stacked and fixed, mixed vibration mode bending vibration in longitudinal vibration is applied is a piezoelectric vibrator is excited, The reinforcing plate is generated by the bending vibration and a first cutout portion including a central portion of the piezoelectric vibrator or the reinforcing plate or the piezoelectric element generated by the longitudinal vibration and including a central portion where the strain is maximum. The piezoelectric vibrator, the reinforcing plate, or a second punched-out portion including a portion where the strain of the piezoelectric element is maximum is formed, and the contact area between the reinforcing plate and the piezoelectric element is , characterized in that the formation of the first void part is smaller than the area of the piezoelectric element.
The strain caused by the longitudinal vibration means a ratio of a displacement amount to a predetermined unit length in a piezoelectric vibrator (or a piezoelectric element or a reinforcing plate, hereinafter the same).
Here, it is assumed that the node of the longitudinal vibration is a portion where the distortion of the piezoelectric vibrating body caused by the longitudinal vibration is maximized. On the other hand, the antinodes of longitudinal vibration are the parts where the distortion is minimized.
The node is a portion where the amplitude is almost zero in the piezoelectric vibrating body, and the antinode is the portion that swings most at the amplitude in the piezoelectric vibrating body.
With respect to each invention described in this specification, the “location where the distortion caused by the longitudinal vibration is maximized” corresponds to a longitudinal vibration node. The longitudinal vibration node is a position on a line that bisects the size of the piezoelectric vibrating body in the vibration direction of the longitudinal vibration, and the central portion is in a direction orthogonal to the vibration direction of the longitudinal vibration in the longitudinal vibration node. Refers to the central position of. That is, for example, in the case of a rectangular plate-like piezoelectric vibrating body, the position on the line that bisects the length of the piezoelectric vibrating body is a longitudinal vibration node, and the central portion is the piezoelectric vibration in the longitudinal vibration node. It is a central position portion in the width direction of the body.

According to the present invention, the first cut-through portion is formed in the reinforcing plate including the central portion of the portion where the distortion of the piezoelectric vibrating body is maximum in the longitudinal vibration mode. The reinforcing plate does not come into contact with the piezoelectric element, and the reinforcing plate has resistance to expansion and contraction of the piezoelectric element and can suppress the vibration.
Here, the graph of FIG. 36 shows the magnitude of distortion of the piezoelectric vibrating body due to longitudinal vibration. The horizontal axis in FIG. 36 corresponds to the y axis shown in FIG. That is, the horizontal axis of FIG. 36 indicates the distance from the longitudinal center (point O) of the rectangular piezoelectric vibrator (FIG. 37) to an arbitrary position on the y axis. In FIG. 36, the length from the center in the longitudinal direction (point O) to the short side of the piezoelectric vibrating body is 100 (see FIG. 37). On the other hand, the vertical axis in FIG. 36 indicates the magnitude of distortion of the piezoelectric vibrating body caused by longitudinal vibration (the maximum value is 100). FIG. 36 and FIGS. 40 and 41 to be described later show data of the piezoelectric vibrating body in which a portion cut through the reinforcing plate is not formed.

  The graph of FIG. 36 is calculated by the following equation (1).

Each parameter in said Formula (1) is demonstrated with reference to FIG.
εd: magnitude of strain of the piezoelectric vibrator at an arbitrary position on the y-axis l: length from the longitudinal center (point O) to the short side of the piezoelectric vibrator ρ: density of the piezoelectric vibrator a: piezoelectric vibrator Acceleration when moving due to elongation E: Young's modulus of the piezoelectric vibrator y: Distance from the longitudinal center (point O) of the piezoelectric vibrator to any point on the y-axis

The correctness of the data shown in the graph of FIG. 36 was verified based on the detection signal from the detection electrode provided on the piezoelectric element. Specifically, the detection electrode 105 insulated from the drive electrode 104 as shown in FIG. 38 is formed on the surface of the piezoelectric element bonded to the front and back of the rectangular reinforcing plate that does not have the cut-through portion, The magnitude of the detection signal output from the detection electrode 105 is measured. Since the magnitude of the detection signal substantially represents the magnitude of the distortion, the magnitude of the distortion can be measured by measuring the detection signal. The drive electrode 104 is formed on the entire surface of the piezoelectric element excluding the detection electrode 105. By applying a drive signal (an AC signal in the vicinity of the longitudinal resonance frequency) to this drive electrode 104 (voltage application), the portion where the drive electrode 104 is provided is actively distorted. Due to this active strain, the portion provided with the detection electrode is passively distorted, and a voltage signal indicating the vibration state of the piezoelectric vibrating body is output from the detection electrode.
Here, the location where the detection electrode 105 is formed is changed along the center line C1 along the longitudinal direction of the piezoelectric vibrator (FIG. 38), and the magnitude of the distortion at each location is based on the magnitude of the detection signal. As a result of the measurement, the result data showed a tendency close to the above formula (1). Accordingly, the relationship between an arbitrary position y (FIG. 37) on the y-axis from the longitudinal center to the short side of the piezoelectric vibrating body and the magnitude of strain caused by the longitudinal vibration is generally as shown in FIG. I can say that.

By the way, the node of the longitudinal vibration in the piezoelectric vibrating body is a position on the center line C2 (FIG. 38) along the width direction of the piezoelectric vibrating body. It can be seen that the position is on the center line C2. Based on the verification of the vibration energy density in such a piezoelectric vibrating body, at least the central portion of the portion where the strain caused by the longitudinal vibration is maximized is opened by the first cutout portion, so that the in-plane direction of the reinforcing plate The amplitude of the longitudinal vibration that expands and contracts along can be reliably increased. In this way, the amplitude of the longitudinal vibration can be reliably increased without being reduced since the displacement of the piezoelectric element in the out-of-plane direction can be regulated by the portion where the first cut-out portion of the reinforcing plate is not vacant while the amplitude is increased. The
As the amplitude is expanded in this way, when the piezoelectric vibrator is used as an actuator, a driven body with a larger load can be driven at a higher speed even with the same input power, thereby improving driving efficiency. Is possible. On the other hand, since it becomes possible to drive a driven body with a predetermined load even if the input power is reduced, it is possible to reduce the electric capacity of a power source such as a battery, and to reduce the size of various devices on which a piezoelectric vibrator is mounted and Thinning can also be promoted.

FIG. 39 shows an example of a mode in which a driven body is driven by a piezoelectric vibrating body that mainly excites longitudinal vibration according to the present invention. As shown in this figure, the piezoelectric vibrating body 91 is disposed substantially along the tangent line L with the rotor 92, and the rotor 92 is moved by the movement of the protrusion 911 as a contact portion provided on the piezoelectric vibrating body 91. It is pressed and driven in the direction of the tangent L. When the piezoelectric vibrating body 91 is arranged as shown in FIG. 39, the amplitude of the longitudinal vibration is increased, so that the driving distance of the rotor by the pressing for each vibration cycle of the protrusion 911 is increased, and as a result, the driving speed is reduced. In addition to being able to improve, it becomes possible to drive a driven body having a large load due to a large torque.
In addition, the moving direction of the driven body (rotation direction in the case of a rotor) is not limited to one direction, and the rotor may be driven in both the rightward rotation and the leftward rotation, for example.
Further, the driven body is not limited to the rotor, and may be driven linearly.
The piezoelectric actuator is, for example, a driving device such as a date dial or a pointer of a watch, a zoom mechanism or an autofocus mechanism in a lens module of a camera, an inkjet head or paper feeding mechanism of a printer, a piezoelectric buzzer, a driving device in a movable toy, etc. Can be used for

Further, in pressure electrostatic vibrator of the present invention, mixed vibration mode bending vibration to the longitudinal vibration is applied is Ru is excited.

  As described above, the amplitude of the longitudinal vibration is increased by the first cut-out portion formed in the reinforcing plate, for example, the amplitude of the bending vibration as the secondary vibration induced by the longitudinal vibration is also increased. Become. The configuration is not limited to the configuration in which the bending vibration is induced by the longitudinal vibration, and the configuration in which the longitudinal vibration and the bending vibration are each actively excited may be used. In the mixed mode of the longitudinal vibration and the bending vibration according to the present invention, an elliptical motion that can drive the driven body with high efficiency can be generated in the piezoelectric vibrator, and the amplitude of the longitudinal vibration and the amplitude of the bending vibration can be increased. Through the synergy, vibration efficiency can be greatly improved.

Further, in the above pressure electrostatic vibrator of the present invention that mixed vibration mode is excited is the reinforcing plate, the distortion of the piezoelectric transducer or the reinforcing plate or the piezoelectric element produced by sinusoidal vibration is hollowed include portions of maximum and second void portion that is formed.

The distortion caused by the bending vibration means a ratio of a displacement amount to a predetermined unit length in a piezoelectric vibrating body (or a piezoelectric element or a reinforcing plate, hereinafter the same).
According to the present invention, since the portion where the distortion caused by the bending vibration is maximized is opened when the reinforcing plate is cut through, the reinforcing plate does not come into contact with the piezoelectric element at the second cut-through portion. Can prevent the vibration from being disturbed.
Here, the graph of FIG. 40 shows a piezoelectric vibrating body due to bending vibration on the x-axis in FIG. 37 (the axis in the direction perpendicular to the long side passing through the center O, the axis perpendicular to the y-axis and the axis in the width direction). Indicates the magnitude of distortion. The horizontal axis in FIG. 40 corresponds to the x-axis shown in FIG. That is, the horizontal axis of FIG. 40 is the distance from the center (point O) in the width direction of the rectangular piezoelectric vibrator (FIG. 37) to any point on the x-axis (distance in the width direction, distance in the long side direction). ). In FIG. 40, the length from the center in the width direction (point O) to the long side of the piezoelectric vibrating body is 100 (see FIG. 37). On the other hand, the vertical axis in FIG. 40 indicates the magnitude of distortion caused by the bending vibration on the x-axis in FIG. 37 (the maximum value is 100). As can be seen from FIG. 40, the strain due to the bending vibration mode gradually increases from the center in the width direction (point O) toward the outer edge portion on the long side of the piezoelectric vibrating body along the x axis. Note that the magnitude of the absolute value of the strain caused by the bending vibration on the vertical axis in FIG. 40 differs depending on the position on the y-axis (FIG. 37). In FIG. 37, the absolute value of the distortion at the position 37 away from the center point O is maximized with the distance from the center point O to the short side being 100, and the distance from the position 37 toward the center point O is as described above. The distortion becomes smaller, and the distortion becomes smaller toward the position away from the 37 to 74. The above-mentioned tendency of the strain is true on both the upper side and the lower side in FIG.
For this reason, in order to avoid the hindrance of expansion and contraction of the piezoelectric element by the reinforcing plate, it is conceivable that the reinforcing plate is not provided on the outer edge portion on the long side of the piezoelectric vibrating body. However, if the outer edge portion of the reinforcing plate is pierced over a wide range as shown in FIG. 32 described above, the vibration in the Z-axis direction that is not originally intended increases as shown in FIG.

  The graph of FIG. 40 is calculated by the following equation (2).

Each parameter in the above equation (2) will be described with reference to FIG.
M _y : Bending moment received by bending vibration at a location separated by an arbitrary distance y from the point O along the y-axis E: Young's modulus b of the piezoelectric vibrator b: Thickness h of the piezoelectric vibrator h: Width of the piezoelectric vibrator x: Distance from the center in the width direction (point O) of the piezoelectric vibrator to any point on the x-axis

The correctness of the data shown in the graph of FIG. 40 was verified based on the detection signal from the detection electrode provided on the piezoelectric element.
Here, the location where the detection electrode 105 is formed is changed along the parallel line of the center line C2 along the width direction of the piezoelectric vibrator (FIG. 38), and the magnitude of the distortion at each location is changed to the magnitude of the detection signal. As a result of measurement based on the results, the result data showed a tendency close to the above formula (2). An AC signal near the bending resonance frequency was applied to the drive electrode. From the above, the relationship between the distance x from the center in the width direction of the piezoelectric vibrating body to an arbitrary location on the x-axis that is the width direction and the magnitude of strain caused by bending vibration on the x-axis is generally shown in FIG. It can be said that

FIG. 41 shows the vibration behavior of the secondary bending vibration in the center line (see C1 in FIG. 38) along the longitudinal direction of the rectangular piezoelectric vibrator. The vertical axis in FIG. 41 indicates the amount of displacement (amplitude) in the width direction of the piezoelectric vibrator, and the maximum value of this vertical axis is 100. On the other hand, the horizontal axis of FIG. 41 shows the distance from the longitudinal center (point O) of the piezoelectric vibrator (see FIG. 37) to an arbitrary position on the y axis in the length direction. The maximum value was 100. The length of the rectangular piezoelectric vibrator in the example of FIG. 41 is 3.5 mm, and the width is 1.0 mm (the same reinforcing plate and piezoelectric element are used in FIGS. 36 to 38 and 40 as well). is there. As shown in FIG. 41, the displacement in the width direction of the piezoelectric vibrator is a maximum at a distance of about 37% when the length from the longitudinal center (point O) to the short side of the piezoelectric vibrator is 100%. There is a point P. The position taking this point P is the antinode of bending vibration. As shown in FIG. 40, since the distortion at the outer edge portion is larger than the inner (center side) portion in the width direction of the piezoelectric vibrating body, the piezoelectric vibrating body has 37 in the short side direction from the plane center position. The distortion caused by flexural vibration is maximized at the position of the intersection of the straight line along the width direction of the piezoelectric vibrator at the point P and the outer edge (long side) at the point P separated by%. That is, the intersection point is a portion where the distortion caused by the bending vibration in the piezoelectric vibrating body is maximized (the energy density of the bending vibration is maximized).
Based on the verification of the vibration energy density in such a piezoelectric vibrating body, a portion where the magnitude of strain caused by bending vibration is maximized is opened as the second cut-out portion, and this opening allows the amplitude of the bending vibration. Can be expanded reliably. In this way, the amplitude of the flexural vibration in the in-plane direction of the reinforcing plate can be reliably prevented from being reduced since the displacement of the piezoelectric element in the out-of-plane direction can be regulated by the portion of the reinforcing plate that is not penetrated while the amplitude is expanded. Expanded to

  That is, according to the present invention, in the mixed mode of longitudinal vibration and bending vibration, in addition to the formation of the first cutout portion including the portion where the distortion caused by the longitudinal vibration is maximum, the bending vibration causes By reinforcing the reinforcing plate including the portion where the generated strain is maximum, the amplitudes of both the longitudinal vibration and the bending vibration can be expanded, and the locus of the elliptical motion can be expanded. As a result, the vibration efficiency is further improved, and when the piezoelectric vibrator is used as an actuator, the drive efficiency can be further improved and the size can be further reduced.

Wherein the pressure conductive vibrator of the present invention that mixed vibration mode is excited, the reinforcing plate includes a first void part is a central part which is formed from one end of the piezoelectric element in the vibration direction of the longitudinal vibration In the trunk line part extending through the central part to the other end part, between one end part of the trunk line part and the central part, and between the other end part of the trunk line part and the central part, respectively. One or more branch portions formed so as to intersect the main line portion, and in a region adjacent to the main line portion and the branch portion, the outer edge portion of the reinforcing plate faces the main line portion. It is preferable that the second cut-through portion that is cut through is formed.

According to the present invention, the trunk portion becomes the support column, and the skeleton is formed by the trunk portion, the center portion, and the branch portion. Therefore, the displacement of the piezoelectric element in the out-of-plane direction can be well regulated by this skeleton. As a result, the vibration efficiency can be further improved.
The shape of the reinforcing plate when the number of branches is large is similar to a fish bone.
Further, the main line portion may not be formed linearly as long as it extends from one end portion of the piezoelectric element or the reinforcing plate to the other end portion, and may extend in an S shape, for example.
The strain generated by the bending vibration means the ratio of the displacement amount to the predetermined unit length when the bending vibration is generated in the piezoelectric vibrating body (or piezoelectric element or reinforcing plate, hereinafter the same). Therefore, the portion where the distortion of the piezoelectric vibrating body caused by the bending vibration becomes maximum corresponds to the antinode of the bending vibration and the portion corresponding to the outer edge portion of the reinforcing plate or the piezoelectric element. The node is a portion where the amplitude is almost zero in the piezoelectric vibrating body, and the antinode is the portion where the amplitude is maximum (see the position of point P in FIG. 41) in the piezoelectric vibrating body.

FIG. 42 shows an example of a mode in which a driven body is driven by a piezoelectric vibrating body that mainly excites bending vibration as a reference technique of the present invention. As shown in this figure, the piezoelectric vibrating body 93 is disposed along the normal direction of the tangent L to the rotor 92, and the rotor is moved by the movement of the protrusion 931 as a contact portion provided on the piezoelectric vibrating body 93. 92 is pressed in the direction of the tangent L and driven. When the piezoelectric vibrating body 93 is arranged as shown in FIG. 42, the driving distance of the rotor by the pressing for each vibration cycle of the protrusion 931 is increased by increasing the amplitude of the bending vibration, and as a result, the driving speed is increased. In addition, it becomes possible to drive the driven body having a large load due to a large torque.
The driven body is not limited to the rotor and may be driven linearly.

Then, the pressure electrostatic vibrator of the present invention, the elastic modulus of the reinforcing plate performing oscillation is usually (for example, Young's modulus) is at higher than the elastic modulus of the piezoelectric element, in which case the vibration characteristics of the reinforcement plate In order to improve the area, the area where the reinforcing plate and the piezoelectric element are in contact is smaller than the area of the piezoelectric element when the reinforcing plate is provided with the first cutout portion or the second cutout portion. It is preferable. In the present invention, the rigidity of the reinforcing plate and the rigidity of the piezoelectric element can be made closer to each other.
Moreover, it is preferable that the main body and the support portion of the reinforcing plate are formed so as not to overlap in plan view. Thereby, since a 1st cut-through part does not overlap with a support part and the movement of the main body of a reinforcement board is not prevented.
When the outer shape of the reinforcing plate is left as a contour portion, the shape (for example, a rectangle) of the piezoelectric element preferably matches the outer shape (for example, a rectangular shape) of the reinforcing plate that is not hollowed out. This makes it possible to easily and accurately position the relative position between the reinforcing plate and the piezoelectric element when the reinforcing plate formed with the cut-through portion is bonded to the piezoelectric element. Variation is suppressed.

The pressure electrostatic vibrator of the present invention, the reinforcing plate is outer shape in plan view in a state that is not hollowed is a substantially rectangular, at least one of the void part, the double the width of the reinforcing plate It is preferable that the center line is equally symmetrical with respect to the equally dividing center line.

According to this invention, the regulating force of the reinforcing plate against the displacement in the out-of-plane direction of the piezoelectric element can be exhibited symmetrically on both sides of the center line. For this reason, when the vibration behavior of the piezoelectric vibrating body is switched line-symmetrically to the center line, the vibration characteristics can be made equal on both sides of the center line. Thereby, it is possible to equalize the driving characteristics when the vibration of the piezoelectric vibrating body is transmitted and the driven body is driven in one direction and the opposite direction.
The “drilled through part” is a generic term for all of the first cutout part, the second cutout part, and the third cutout part. The same applies to the following description.

The pressure electrostatic vibrator of the present invention, at least one of the void part, it is preferable that the member formed elastic modulus at small material are arranged than the material of the reinforcing plate.

According to this invention, the strength of the reinforcing plate is ensured by disposing the member having a low elastic modulus in the first cutout portion, the second cutout portion, or the third cutout portion as a separate member from the reinforcing plate. However, the amplitude can be greatly increased without hindering the displacement of the piezoelectric element in the in-plane direction.
In addition, the member whose elastic modulus is smaller than the reinforcing plate (for example, Young's modulus is small) can be formed of resin, solder, or the like when the reinforcing plate is a metal such as steel.

The pressure electrostatic vibrator of the present invention, the reinforcing plate, the abuts on the driven member has an abutting portion for driving the driven body, the first void part is the piezoelectric vibrators It is preferable to include a portion where the strain generated by the longitudinal vibration is maximum or substantially maximum in a state where the reaction force of the driven body is received.
In pressure electrostatic vibrator of the present invention is also the reinforcing plate has a contact portion for driving the driven member abuts on the driven member, the second void part is the piezoelectric vibrators It is preferable to include a portion where the strain generated by the bending vibration is maximized or substantially maximized while receiving the reaction force of the driven body.

In these inventions, the piezoelectric vibrating body is used as an actuator for driving the driven body. Here, when the piezoelectric vibrating body vibrates in response to the reaction force from the driven body , the first cut-out portion is formed so as to include a portion where the strain caused by the longitudinal vibration is maximum or substantially maximum, and the bending vibration causes By forming the second cut-out portion so as to include a portion where the generated strain is maximum or substantially maximum, it is possible to cope with the vibration behavior of the piezoelectric element in conformity with the use of the piezoelectric vibrating body as an actuator. That is, during the operation of the piezoelectric actuator, even if the vibration characteristics of the piezoelectric vibrating body slightly deviate from the vibration characteristics when the piezoelectric vibrating body is vibrated alone due to the reaction force of the driven body, While restricting the displacement in the out-of-plane direction, it is possible to reliably increase the amplitude and realize good vibration characteristics.
The contact portion may be integrated with the reinforcing plate or may be separate.

A piezoelectric actuator according to the present invention includes the above-described piezoelectric vibrating body and a driven body that is driven by vibration transmitted from the piezoelectric vibrating body.
According to the present invention, since the piezoelectric vibrator described above is provided, the above-described functions and effects can be enjoyed.

A portable device according to the present invention includes the above-described piezoelectric actuator.
According to the present invention, since the piezoelectric vibrator described above is provided, the above-described functions and effects can be enjoyed.
Here, examples of the portable device include a wristwatch, a pocket watch, a digital camera, a digital video, a portable printer, a portable information device, a cellular phone, and the like.

The portable device according to the present invention is preferably a timepiece including a timekeeping unit and a time information display unit that displays information timed by the timekeeping unit, and the timed information display unit is driven by the driven body.
According to the present invention, it is possible to display time information such as time and calendar by driving a gear or the like using the piezoelectric vibrator as an actuator. According to the piezoelectric vibrator described above, the amplitude is greatly enlarged, so that a heavy member with a large load can be driven, and continuous driving such as a second hand having a high driving speed, and quick return of a pointer are possible. Etc. are also possible. In addition, since the amplitude is increased and the drive efficiency with the same input power is improved, the applied voltage can be lowered and a small and thin battery with a small battery capacity can be used, so the watch can be further reduced in size and thickness. It becomes.
In addition, advantages of the piezoelectric actuator, that is, not affected by magnetism, high responsiveness, and the like can be realized.

  The drive efficiency can be greatly improved by the present invention described above.

Embodiments of the present invention will be described below with reference to the drawings.
In the description of the second and subsequent embodiments, the same components as those of the first embodiment described below are denoted by the same reference numerals, and description thereof is omitted or simplified.

[First Embodiment]
In this embodiment, a wristwatch equipped with a chronograph is shown as a portable device. Further, in the present embodiment, a configuration is shown in which the amplitude of longitudinal vibration can be increased, and thereby the amplitude of bending vibration can also be increased.

[1. overall structure]
FIG. 1 is a plan view showing a timepiece 1 of the present embodiment. The timepiece 1 includes a movement 2, a dial plate 3 for displaying time, an hour hand 4, a minute hand 5, and a second hand 6, and a chronograph second hand 7A and a chronograph minute hand 7B for indicating chronograph time.
The hour hand 4, the minute hand 5, and the second hand 6 are the same as ordinary analog quartz, and are a circuit board in which a crystal unit is incorporated, a step motor having a coil, a stator and a rotor, a driving wheel train, a battery And driven by.

[2. Chronograph second hand drive mechanism]
The driving mechanism for driving the chronograph second hand 7A includes a piezoelectric vibrating body 20A, a rotor 25 as a driven body that is rotationally driven by the piezoelectric vibrating body 20A, and a reduction wheel train 26 that transmits the rotation of the rotor 25 while reducing the rotation. And is configured. These piezoelectric vibrators 20A and the rotor 25 constitute a piezoelectric actuator 20.
The reduction gear train 26 includes a gear 261 that is arranged coaxially with the rotor 25 and rotates integrally with the rotor 25, and a gear 262 that meshes with the gear 261 and is fixed to the rotation shaft of the chronograph second hand 7A. Has been.
The piezoelectric actuator 20, the rotor 25, and the gear 261 are unitized as a piezoelectric actuator unit 10 as shown in FIG.

[3. Configuration of piezoelectric actuator unit]
A piezoelectric actuator unit 10 shown in FIG. 2 has a support plate 12 fixed to a base plate of the timepiece 1 by a fixing member 11 such as a screw, a piezoelectric vibrating body 20A fixed to the support plate 12, and a support plate 12 that is freely rotatable. And a rotor 25 and a gear 261 attached thereto. Here, the piezoelectric actuator 20 of the present embodiment is configured to include a piezoelectric vibrating body 20A and a rotor 25. In addition, the rotation amount (rotation position) of the gear 261 is detected by the rotation sensor 13 disposed above the gear 261.
A base member 14 to which the piezoelectric actuator 20 is attached is fixed to the support plate 12.

[4. Configuration of piezoelectric actuator]
FIG. 3 shows a piezoelectric vibrating body 20A constituting the piezoelectric actuator 20, and the piezoelectric vibrating body 20A is formed in a substantially rectangular plate shape as a whole.
The piezoelectric vibrating body 20A includes two rectangular plate-shaped piezoelectric elements 21 and 21 and a reinforcing plate 30 formed of stainless steel or the like. A piezoelectric vibrating body 20A is configured by laminating and bonding the piezoelectric elements 21 and 21 to the front and back surfaces of the reinforcing plate 30, respectively.

[4-1. Configuration of piezoelectric element]
In this embodiment, lead zirconate titanate (PZT (registered trademark)) is used for the piezoelectric elements 21 and 21. In addition, quartz, lithium niobate, barium titanate, lead titanate, and metaniobic acid are used. Lead, polyvinylidene fluoride, lead zinc niobate, lead scandium niobate, and the like can also be used.
An electrode surface formed by plating, sputtering, vapor deposition, or the like is formed on the surface of each piezoelectric element 21. This electrode surface is divided by grooves 230 formed by etching or the like, so that five electrodes 231 to 235 are formed on the surface of each piezoelectric element 21. These electrodes 231 to 235 are similarly arranged in each piezoelectric element 21. For example, on the back side of the electrode 235 arranged on the front body surface in the front side piezoelectric element 21 in FIG. An electrode 235 is arranged on the body surface on the back side. That is, the respective electrodes of the front-side piezoelectric element 21 and the back-side piezoelectric element 21 coincide with each other in plan view.
On the other hand, the surface opposite to the surface on which the electrodes 231 to 235 are formed in each of the piezoelectric elements 21 on the front side and the back side is in contact with the reinforcing plate 30. That is, the reinforcing plate 30 also functions as an electrode for each piezoelectric element 21.
An electrode may be formed over the entire surface of the piezoelectric elements 21 and 21 on the side where the reinforcing plate 30 is laminated. In this case, the electrode and the reinforcing plate 30 are electrically connected.
Here, the dimensions of the piezoelectric element 21 are determined such that the ratio of width to length is 2: 7, and in this embodiment, the width is 1 mm and the length is 3.5 mm.

[4-2. Reinforcement plate configuration]
FIG. 4 is a plan view showing the shape of the reinforcing plate 30 in the piezoelectric vibrating body 20A. The reinforcing plate 30 includes a rectangular reinforcing plate main body 31 in which the piezoelectric elements 21 and 21 are laminated on the front surface and the back surface, and a pair of supporting portions provided on both side surfaces on the long side of the reinforcing plate main body 31. 32, 32, a protrusion 33 that is an abutting portion provided continuously on the short side of the reinforcing plate body 31, and a protrusion 34 for securing a vibration balance with respect to the protrusion 33. Are integrally formed.
The reinforcing plate 30 of the present embodiment is made of stainless steel that has conductivity and is nonmagnetic, but the material of the reinforcing plate is not limited to this. Examples of the nonmagnetic material used for the reinforcing plate include metal materials such as austenitic stainless steel, aluminum, aluminum alloy, copper, and copper alloy, resin materials such as polyimide, and ceramic materials. Here, when a conductive material such as various metal materials is used for the reinforcing plate, the reinforcing plate can be used as an electrode of the piezoelectric element. Therefore, a separate electrode is formed on the piezoelectric element laminated on the reinforcing plate. There is an advantage that it is not necessary. Further, when a nonmagnetic material is used for the reinforcing plate, there is an advantage that a magnetic field outside the timepiece or a magnetic field generated by a step motor incorporated in the timepiece does not affect the operation of the piezoelectric actuator 20. Although the piezoelectric actuator has a structure that is less susceptible to the influence of the magnetic field than the step motor, the use of a non-magnetic material for the reinforcing plate makes it less susceptible to the influence of the magnetic field. A magnetic material may be used for the reinforcing plate.
The length and width of the reinforcing plate body 31 are the same as the length and width of the piezoelectric element 21, respectively, and a through-hole 310 as a first cut-out portion is formed in the center of the plane of the reinforcing plate body 31. Yes. That is, the contact area between the reinforcing plate main body 31 and the piezoelectric element 21 that vibrates following the vibration of the piezoelectric element 21 is smaller than the area of the piezoelectric element 21, thereby the vibration characteristics of the piezoelectric vibrating body 20 </ b> A. Can be improved.
Here, the reinforcing plate main body 31 and the support portions 32 and 32 are formed so as not to overlap in plan view. Therefore, since the support portions 32 and 32 are not provided in the through-hole 310, the support portions 32 and 32 do not hinder the movement of the reinforcing plate body 31.
Piezoelectric elements 21 and 21 are joined to the reinforcing plate body 31 other than the through hole 310 with an epoxy adhesive.
The through-hole 310 is formed symmetrically about a center line Y that bisects the width of the piezoelectric element 21.

Each support portion 32 has a connecting portion 321 provided continuously to the reinforcing plate body 31 and a fixing portion 322 fixed to the base member 14 with the screw 15 (FIG. 2), and is not laminated with the piezoelectric element 21. The piezoelectric element 21 is supported in a state protruding from the outer edge of the piezoelectric element 21. A fixing hole 322A through which the screw 15 is inserted and a positioning hole 322B are formed in the fixing portion 322.
The connecting portion 321 may be formed narrow so as to apply a spring force to the driven main body 31. The protrusion 33 is elastically pressed against the rotor 25 by the spring force, and the rotor 25 is rotationally driven by the excitation of the piezoelectric vibrating body 20. The structure for applying the spring force is not limited to the above, and any structure may be used.
The connecting portions 321 in each support portion 32 are respectively provided on both sides in the width direction of the piezoelectric element 21 along a line XX passing through a longitudinal vibration node (line segment A) excited by the piezoelectric vibrating body 20A. . The line segment A is a line segment that passes through the center of the plane of the piezoelectric element 21 and extends along the direction orthogonal to the longitudinal direction of the piezoelectric element 21 and has the outer edge portion 21A of the piezoelectric element 21 as both ends.

The protrusion 33 is set at a relative position to the rotor 25 so as to come into contact with the outer peripheral surface of the rotor 25 (FIG. 2) with a predetermined force, and between the protrusion 33 and the rotor 25 side surface. By generating an appropriate frictional force, the vibration of the piezoelectric vibrating body 20 </ b> A is transmitted to the rotor 25.
In the present embodiment, a protrusion 34 serving as a counter is provided on the side not in contact with the rotor 25 with the same shape and mass as the protrusion 33.

[5. Electrical configuration of piezoelectric vibrator]
FIG. 5 shows electrical connection of the piezoelectric vibrating body 20A. The piezoelectric vibrator 20A is provided with a lead substrate (not shown), and the electrodes 231 to 235 and the reinforcing plate 30 provided on the piezoelectric element 21 are connected to the drive circuit 28 via the lead substrate. .
The reinforcing plate 30 is connected to the GND as a common electrode for each of the piezoelectric elements 21 and 21, and is connected between the electrodes 231 to 235 of one piezoelectric element 21 and the reinforcing plate 30 by the drive circuit 28, and of the other piezoelectric element 21. An AC voltage is applied between each of the electrodes 231 to 235 and the reinforcing plate 30. The electrodes 231 to 235 are selectively used as will be described later. However, the same electrodes provided in the piezoelectric elements 21, that is, the electrodes 231 and 231, the electrodes 232 and 232, the electrodes 233 and 233, and the electrode 234, respectively. , 234 and electrodes 235 and 235 are simultaneously applied with the same potential.

A single-phase drive voltage is applied to the piezoelectric vibrating body 20A by the drive circuit 28.
Here, the frequency of the drive voltage (drive frequency) is determined in consideration of the resonance point of longitudinal vibration and the resonance point of bending vibration in the piezoelectric vibrating body 20A.
FIG. 6 shows the relationship between the driving frequency and the impedance in the piezoelectric vibrating body 20A. As shown in FIG. 6, there are two resonance points where the impedance is minimum and the amplitude is maximum with respect to the drive frequency. Of these, the lower one is the resonance point of longitudinal vibration and the higher one is bending vibration. Resonance point.
That is, when the piezoelectric vibrating body 20A is driven between the longitudinal resonance frequency fr1 of the longitudinal vibration and the bending resonance frequency fr2 of the bending vibration, the amplitudes of both the longitudinal vibration and the bending vibration are ensured, and the piezoelectric actuator 20 is driven with high efficiency. . Note that, by making the longitudinal resonance frequency fr1 and the bending resonance frequency fr2 close to each other, it is possible to set a driving frequency at which both the amplitude of the longitudinal vibration and the amplitude of the bending vibration become larger.

[6. Action of piezoelectric vibrator]
FIG. 7 shows the vibration behavior of the piezoelectric vibrating body 20A. In the present embodiment, a potential is selectively applied to each of the electrodes 231 to 235 provided on the piezoelectric element 21.
First, when a potential is applied to the electrode 233 provided along the longitudinal direction at the center of the plane of the piezoelectric element 21 and the electrodes 231 and 235 disposed symmetrically with respect to the plane center of the piezoelectric element 21, Due to the expansion and contraction of the piezoelectric element 21 due to voltage application to the portions where the electrodes 231, 233 and 235 are provided, the piezoelectric vibrating body 20 </ b> A excites a longitudinal primary vibration along the longitudinal direction and A bending secondary vibration is induced in the width direction of the piezoelectric element 21 by the moment generated by the unbalance. Accordingly, the piezoelectric vibrating body 20 </ b> A vibrates in a mixed mode in which longitudinal vibration and bending vibration are combined. The longitudinal vibration and bending vibration are held by the reinforcing plate body 31 stacked on the piezoelectric element 21. Thus, the reinforcing plate 30 is along the in-plane direction.

Here, as already shown in the graph of FIG. 36, the longitudinal vibration node (shown by A in FIG. 7) has the maximum distortion (the vibration energy density of the longitudinal vibration is maximum) in the piezoelectric vibrating body 20A. A through hole 310 is formed in the reinforcing plate main body 31 including the center portion of the node of the longitudinal vibration (in this embodiment, the plane center portion of the piezoelectric vibrating body 20A). That is, the inside of the through-hole 310 includes a central portion where the distortion caused by the longitudinal vibration is maximum.
In the through hole 310 including a part of the line segment A in which the maximum strain is generated by the longitudinal vibration, the reinforcing plate body 31 and the piezoelectric element 21 are not in contact with each other, and the piezoelectric element 21 expands and contracts freely. Thus, the amplitude can be expanded by the maximum vibration energy that can be generated by the expansion and contraction of 21.
In addition to this, the piezoelectric element 21 is held on the surface of the reinforcing plate body 31 except for the through-hole 310, and this restricts the displacement of the piezoelectric element 21 in the out-of-plane direction. Without being reduced, the amplitude of the longitudinal vibration in the piezoelectric vibrating body 20A can be substantially maximized. In addition, the amplitude of the longitudinal vibration becomes maximum at the short side portion of the piezoelectric vibrating body 20A.
And the amplitude of a longitudinal vibration induced by a longitudinal vibration will also be expanded by expanding the amplitude of a longitudinal vibration in this way.

  Here, the through-hole 310 is 1/20 (or 5%) or more of the length of the piezoelectric element 21 along the longitudinal direction of the piezoelectric element 21 from the position on the line segment A where the distortion caused by the longitudinal vibration is maximum. Since the openings are opened to the separated positions, the vibration energy density distribution of the piezoelectric vibrating body 20A is affected by the reaction force of the rotor 25 (FIG. 2) with which the projection 33 abuts, compared to the case of the piezoelectric vibrating body 20A alone. Even if it is a case where it is displaced to the side away from 25, the through hole 310 still includes a part of the portion where the distortion caused by the longitudinal vibration is maximum.

Due to the predetermined phase difference between the longitudinal vibration and the bending vibration that is the secondary vibration, the piezoelectric vibrating body 20A excites elliptical vibration. Accordingly, the protrusion 33 of the piezoelectric vibrating body 20 </ b> A draws an elliptical locus R <b> 1 that is inclined with respect to the longitudinal center line Y of the piezoelectric element 21. Due to the elliptical motion of the protrusion 33, the rotor 25 (FIG. 2) is pressed in the tangential direction with the protrusion 33 and rotates in the + direction.
On the other hand, when a potential is applied to the central electrode 233 and the point-symmetrical electrodes 232 and 234, the voltage is applied to a region that is line-symmetric with respect to the voltage application region of the piezoelectric element 21 in the above case. The locus of the protrusion 33 is also an elliptical locus R2 that is line-symmetric with R1, and the rotor 25 (FIG. 2) rotates in the negative direction.
By such rotation of the rotor 25, the gear 261 integrated with the rotor 25 also rotates, and the gear 2
As the gear 61 rotates, the gear 262 rotates and the chronograph second hand 7A (FIG. 1) is driven in the forward or reverse direction.

  The drive control may be performed by detecting the vibration of the piezoelectric vibrating body 20A. In this case, when the rotor 25 is driven in the + direction, the piezoelectric vibrating body 20A is driven via the electrodes 232 and 234 to which no driving voltage is applied. A voltage signal indicating the vibration state is detected, and when the rotor 25 is driven in the negative direction, a voltage signal indicating the vibration state of the piezoelectric vibrating body 20A is detected via the electrodes 231 and 235 to which the drive voltage is not applied. Then, the drive frequency, the drive pulse width, and the like may be controlled based on the detected voltage signal.

[7. Effects of this embodiment]
(1) In the piezoelectric actuator 20 that is mounted on the timepiece 1 and operates using a battery as a power source, a line that maximizes the distortion caused by longitudinal vibration based on the verification of the vibration energy density in the piezoelectric vibrating body 20A as shown in FIG. A through hole 310 including a part of the portion A is formed in the reinforcing plate body 31. In such a through-hole 310, the maximum vibration energy in the piezoelectric element 21 is exhibited to increase the amplitude, and the portion other than the through-hole 310 in the reinforcing plate body 31 restricts the displacement of the piezoelectric element 21 in the out-of-plane direction. Therefore, the amplitude of the longitudinal vibration is surely enlarged.
As a result, the driven body (the rotor 25, the gears 261 and 262, and the chronograph second hand 7A) having a larger load with the same input power, or the driven body is driven at a high speed and compared with the chronograph second hand 7A. The second hand driven at a very high speed can be realized.
On the other hand, even if the input power is reduced, the driven body with a predetermined load can be driven, so that the battery capacity can be reduced and the timepiece 1 can be reduced in size and thickness.

(2) As the longitudinal vibration amplitude is increased as in (1), the amplitude of the bending vibration induced by the longitudinal vibration is also expanded, so that the elliptical shape of the piezoelectric vibrating body 20A in the mixed mode of the longitudinal vibration and the bending vibration is increased. The trajectory of vibration can be made larger, and the vibration efficiency can be further improved. Thereby, it becomes possible to drive the driven body having a higher load and to drive the driven body at a higher speed.

(3) Since the through-hole 310 formed in the reinforcing plate body 31 is formed symmetrically with respect to the center line Y along the longitudinal direction of the piezoelectric element 21, the reinforcing plate body against the out-of-plane displacement of the piezoelectric element 21. The regulation force of 31 can be exhibited in line symmetry on both sides of the center line Y. As a result, the vibration characteristics when the protrusion 33 draws the elliptical locus R1 and the vibration characteristics when drawing the elliptical locus R2 are equivalent, and the drive characteristics when the rotor 25 is driven in the + direction and the − direction, respectively. Can be equivalent.

(4) Since the through-hole 310 in the reinforcing plate body 31 is formed in a size, position and shape that takes into account the reaction force of the rotor 25 due to the contact of the projection 33 with the rotor 25, the piezoelectric actuator 20 is in operation. This can correspond to the displacement behavior of the piezoelectric element 21 in FIG. That is, during the operation of the piezoelectric actuator 20, even if the vibration characteristics of the piezoelectric vibrating body 20A slightly deviate from the vibration characteristics when the piezoelectric vibrating body 20A is vibrated alone due to the reaction force of the rotor 25, the reinforcing plate main body 31. As a result, the amplitude of the piezoelectric element 21 can be reliably increased and good vibration characteristics can be realized while restricting the displacement of the piezoelectric element 21 in the out-of-plane direction.

[Modification of First Embodiment]
FIG. 8 shows an example in which a member 35 having an elastic modulus smaller than that of the reinforcing plate 30 is disposed and fixed (by joining or the like) in the inner space of the through hole 310 of the reinforcing plate body 31. The member 35 is a member formed of, for example, resin or solder, and has a small elastic modulus, so that it has almost no drag when the piezoelectric element 21 expands and contracts, and the inside of the through hole 310 is a space. The effect similar to the effect by (FIG. 4) is show | played.
In addition, by arranging the member 35 different from the reinforcing plate main body in the through hole 310 in this way, the strength of the reinforcing plate main body 31 can be more sufficiently ensured.
As shown in FIG. 9, the member 35 may be provided only in a part of the through hole 310, and the through hole 350 surrounded by the member 35 may be formed in the reinforcing plate body 31, thereby contributing to an increase in amplitude. it can.
Further, in the first embodiment (FIG. 4), even when an adhesive that joins the piezoelectric element 21 and the reinforcing plate body 31 flows into the through hole 310, this adhesive has an elastic modulus higher than that of the reinforcing plate 30. Therefore, the same effect as that of the present modification can be obtained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, a configuration capable of expanding the amplitudes of longitudinal vibration and bending vibration is shown.
FIG. 10 shows a piezoelectric vibrating body 40A of the present embodiment. In the present embodiment, only the shape of the reinforcing plate body 41 laminated on the piezoelectric element 21 is different from that of the first embodiment, and other configurations are the same as those of the first embodiment.

  The reinforcing plate body 41 of the present embodiment has a through hole 310 that is substantially the same as that of the first embodiment, and the outer edge portion 21A along the longitudinal direction of the piezoelectric element 21 on both sides in the width direction of the reinforcing plate body 41, respectively. The punching holes 411 to 414 are formed by cutting from the corresponding edge of the reinforcing plate body 41 to the inside in the width direction of the piezoelectric element 21. These hollow holes 411 to 414 are formed symmetrically with respect to the center line Y, and when the piezoelectric vibrating body 40A vibrates, the distortion caused by bending vibration is maximized as derived from FIG. Locations) are formed at positions corresponding to B1 and B2 (antinodes of bending vibration).

Here, when the vibration behavior of the bending vibration at the center line Y along the longitudinal direction of the piezoelectric vibrating body 40A of the present embodiment is detected, the bending behavior is substantially the same as in FIG. When the distance up to 100% is taken as 100%, there is a point P where the displacement (amplitude) in the width direction of the piezoelectric vibrator becomes a maximum at a distance of about 37%. As shown in FIG. 40, since the distortion on the outer edge portion is larger than the inner (center side) portion in the width direction of the piezoelectric vibrating body 40A, the piezoelectric vibrating body 40A has a short side direction from the plane center position. In B1 and B2, which are intersection points between the straight line along the piezoelectric vibrator width direction at the point P and 37% away from each other, and the outer edge (long side), the distortion caused by the bending vibration is maximized. That is, the positions of the points (locations) B1, B2 (taken at the point P) are locations where the strain caused by bending vibration in the piezoelectric vibrating body 40A is maximum (the energy density of bending vibration is maximum). As described above, based on FIG. 40 and FIG. 41, it can be seen that the portions where the bending vibration distortion is maximum correspond to B1 and B2.
Accordingly, through holes 411 to 414 are formed so as to include these points B1 and B2, respectively. Therefore, the cut-through holes 411 to 414 become the second cut-through portions. In these through holes 411 to 414, the piezoelectric element 21 freely expands and contracts, so that the amplitude can be expanded by the maximum vibration energy that can be generated by the bending vibration of the piezoelectric element 21.
Since the piezoelectric element 21 is held on the surface of the reinforcing plate main body 41 other than the through-holes 411 to 414 and the through-hole 310, the displacement of the piezoelectric element 21 in the out-of-plane direction is restricted. The amplitude of the longitudinal vibration and the bending vibration at 20A can be substantially maximized.

  Here, since the through holes 411 to 414 are opened to include the vicinity of each of the bending vibration points B1 and B2 at which the distortion caused by the bending vibration becomes maximum, the rotor 25 (see FIG. 2) Even when the vibration energy density distribution is changed from the vibration energy density distribution in the piezoelectric vibrator 20A alone due to the reaction force of 2), the holes 411 to 414 have the maximum strain caused by bending vibration. It is included.

The piezoelectric vibrating body 40A of the present embodiment excites elliptical vibration in the mixed mode of longitudinal vibration and bending vibration, as in the first embodiment. However, as described above, the amplitude of the longitudinal vibration and the bending vibration are reduced by the through hole 310. Since the amplitude is increased and the amplitude of the bending vibration is increased by the bored holes 411 to 414, the vibration efficiency is further improved.
In addition, the present embodiment also provides substantially the same effect as the first embodiment.

[Modification of Second Embodiment]
FIG. 11 shows an example in which members 35 made of resin or solder are arranged and fixed in the inner spaces of the through hole 310 and the cut-through holes 411 to 414 of the reinforcing plate body 41, respectively. Since the member 35 has a smaller elastic modulus than the reinforcing plate 30, the member 35 has the same effect as the effect of the second embodiment (FIG. 10) in which the inside of the through hole 310 and the bored hole 411 to 414 is a space. In addition, since the member 35 is disposed in the through hole 310 and the through holes 411 to 414 as described above, the strength of the reinforcing plate body 41 can be more sufficiently ensured.
In addition, this member 35 may be provided only in a part of each of the through-hole 310 and each of the hollow holes 411 to 414. For example, the portion (points B1 and B2) where the distortion caused by the bending vibration is maximized may be opened without providing the member 35, whereby the amplitude can be increased.
Further, in the second embodiment (FIG. 10), even when the adhesive that joins the piezoelectric element 21 and the reinforcing plate body 41 flows into the through hole 310 or the through holes 411 to 414, the adhesive is Since the elastic modulus is smaller than that of the reinforcing plate 30, the same effect as that of the present modification can be obtained.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the present embodiment, a configuration capable of expanding the amplitudes of longitudinal vibration and bending vibration is shown.
FIG. 12 shows a piezoelectric vibrating body 45A of this embodiment. In the present embodiment, only the shape of the reinforcing plate main body 46 laminated on the piezoelectric element 21 is different from the above-described embodiments, and other configurations are the same as those of the above-described embodiments.

The reinforcing plate body 46 has a central portion 461 that is laminated at the center of the plane of the piezoelectric element 21 and has a through hole 310 formed therein, and a central portion 461 between one end portion and the other end portion in the longitudinal direction of the piezoelectric element 21. It has a trunk line portion 462 extending through and a plurality of branch portions 463 formed so as to intersect the trunk line portion 462, and has a shape similar to a fish bone.
A total of six branch portions 463 are provided, one each between the one end 462A and the central portion 461 of the main line portion 462 and the other end 462B and the central portion 461 of the main line portion 462.

In such a reinforcing plate main body 46, the outer edge portion along the longitudinal direction of the piezoelectric element 21 is formed between the two adjacent ones of the one end 462A, the other end 462B, each branch portion 463, and the central portion 461 of the main line portion 462. It cuts out from the position corresponding to 21A toward the main line part 462, and the cut-through holes 471 to 482 are formed by this. These through holes 471 to 482 are formed symmetrically with respect to the center line Y.
Further, the through-holes 472 and 478 are formed including the point (location) B1 (the long side portion position at the position P in the reinforcing plate body 46 as described above) where the strain generated by the bending vibration is maximized. On the other hand, the through-holes 475 and 481 are formed to include the point (location) B2 (the long side position at the position of the point P in the reinforcing plate main body 46 as described above) where the strain generated by the bending vibration is maximum. Yes. Accordingly, the bored holes 472, 478, 475, 481 are the second bored portions.
Further, the length L1 of the bore holes 471 to 482 is 7% or less (preferably 3% or more) of the length of the piezoelectric element 21, and the width W1 of the bore holes 471 to 482 is the piezoelectric element 21. The width is set to 39% or less (preferably 10% or more) of the width of 21. When the perforated holes 471 to 482 are arranged in the above range, the strength of the reinforcing plate is ensured, and the vibration component in the Z-axis direction is reduced during vibration, and the vibration efficiency is improved.

Each of the bore holes 471 to 482 has a shape, a position, and a dimension determined in consideration of a case where the vibration energy density distribution changes due to the reaction force of the rotor 25 (FIG. 2) with which the protrusion 33 abuts. It has been.
In these through-holes 471 to 482, the piezoelectric element 21 freely expands and contracts, so that the amplitude can be increased by the maximum vibration energy that can be generated by the bending vibration of the piezoelectric element 21.

With reference to FIGS. 13 to 16, the vibration behavior of the piezoelectric vibrating body 45A of the present embodiment will be described. FIG. 13 shows a reinforcing plate provided in the piezoelectric vibrating body 45A, and FIG. 14 is a perspective view of the piezoelectric vibrating body 45A. Here, a non-contact portion 49 where the reinforcing plate main body 46 and the piezoelectric element 21 are not in contact is formed in a portion of the reinforcing plate in which the perforated holes 471 to 482 are formed. The non-contact portion 49 is formed at a position corresponding to each of the through holes 471 to 482.
FIG. 15 shows that a voltage is applied to the electrodes 232, 233, and 234 (FIG. 3) in each piezoelectric element 21 of the piezoelectric vibrating body 45A, and no voltage is applied to the electrodes 231 and 235 (FIG. 3). The state which vibrated is shown. FIG. 15 shows a state in which the piezoelectric vibrating body 45A is vibrated with no load without bringing a rotor or the like into contact with the piezoelectric vibrating body 45A.

FIG. 15 shows the result of simulation of the vibration state of the piezoelectric vibrating body 45A by software. FIG. 16 is a diagram showing only the piezoelectric element 21 in the piezoelectric vibrating body 45A during vibration. From these FIG. 15 and FIG. 16, the piezoelectric vibrating body 45A vibrates in the in-plane direction as a whole including not only the non-contact portion 49 but also the portion where the piezoelectric element 21 and the reinforcing plate body 46 are in contact with each other. It can be seen that there is almost no vibration (out-of-plane vibration) in the out-of-plane direction (the direction includes the Z direction). 34 and 35 relating to the reinforcing plate in which the large cut-out portion is formed as described above, the out-of-plane vibration in the non-contact portion 103 is large, and in the portions other than the non-contact portion 103, the reinforcing plate 101 and the piezoelectric element 102 are in contact. The vibration efficiency in the in-plane direction was low because the vibration was hindered. As described above, the behavior of the piezoelectric vibrating body in FIG. 34 is significantly different from the behavior of the piezoelectric vibrating body 45A of the present embodiment.
In the present embodiment, the length L1 of the opening region of the reinforcing plate main body 46 in each of the through holes 471 to 482 remains at 7% or less (preferably 3% or more) of the length of the piezoelectric element 21. The width W1 of the opening region of the reinforcing plate main body 46 in each of ˜482 stays at 39% or less (preferably 10% or more) of the width of the piezoelectric element 21, so that reinforcement other than the through holes 471 to 482 and the through holes 310 The piezoelectric element 21 is held in the plate body 46. As a result, it is possible to improve vibration efficiency without restricting vibration while regulating out-of-plane vibration. This punching effect is exhibited when the length L1 of the opening region due to the punching hole is 3% or more and the width W1 of the opening region due to the punching hole is 10% or more. On the other hand, when the length L1 exceeds 7% or the width W1 exceeds 39%, the strength of the reinforcing plate becomes weak, so that the regulation force of out-of-plane vibration is reduced, and the amplitude is reduced accordingly.

The graph of FIG. 17 shows the vibration amplitude (solid line) of the piezoelectric vibrating body 45A of the present embodiment and the vibration amplitude (broken line) of the piezoelectric vibrating body in which the cutout portion is not formed in the reinforcing plate. The piezoelectric vibrating body whose vibration amplitude is indicated by a broken line is formed in the same manner as the piezoelectric vibrating body of the present embodiment except that the cutout portion is not formed in the reinforcing plate. The horizontal axis of the graph in FIG. 17 represents the frequency of the drive voltage applied to the piezoelectric element. By applying a driving voltage having an appropriate frequency between the longitudinal resonance frequency fr1 corresponding to the resonance point of the longitudinal vibration and the bending resonance frequency fr2 corresponding to the resonance point of the bending vibration, the amplitude of the longitudinal vibration and the bending vibration Both amplitude and amplitude can be increased, thereby improving vibration efficiency. The upper table in FIG. 17 shows the vibration amplitude of the piezoelectric vibrating body 45A corresponding to each scale of the drive frequency in the graph of FIG. 17, and the lower table in FIG. 17 shows the piezoelectric vibration in which the cut-out portion is not formed. Indicates the vibration amplitude of the body.
Here, as illustrated in FIG. 17, the vibration amplitude of the piezoelectric vibrating body 45 </ b> A indicated by the solid line is larger than the vibration amplitude of the piezoelectric vibrating body in which no cut-through portion is formed. That is, since the out-of-plane vibration is restricted as described above and the vibration amplitude is increased because the vibration is not hindered, the elliptical locus drawn by the protrusion 33 of the piezoelectric vibrating body 45A is also increased. It is driven by.
As described above, the piezoelectric vibrating body 45A of this embodiment has high vibration efficiency, and the stop torque of the piezoelectric actuator configured by including the piezoelectric vibrating body 45A and the rotor 25 is a reinforcing plate that does not open a hole. It is improved by about 15% to 20% with respect to the piezoelectric vibrator.

In the piezoelectric vibrating body 45A of the present embodiment, in substantially the same manner as in the second embodiment, a part of the line segment A where the distortion caused by the longitudinal vibration becomes maximum, and the points B1, B2 where the distortion caused by the bending vibration becomes maximum. Since the reinforcing plate main body 46 is opened, the same effects as in the second embodiment can be obtained. In addition, according to the present embodiment, the following effects can be obtained.
(5) The dimension through which the reinforcing plate body 46 is cut is 7% or less of the length of the piezoelectric element 21 and 39% or less of the width, so that the reinforcing plate body 46 moves the piezoelectric element 21 in the out-of-plane direction. It is possible to improve the vibration efficiency without disturbing the vibration while reliably restricting the displacement.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In the present embodiment, a configuration capable of expanding the amplitudes of longitudinal vibration and bending vibration is shown.
FIG. 18 shows a piezoelectric vibrating body 50A of the present embodiment. In the present embodiment, only the shape of the reinforcing plate main body 51 laminated on the piezoelectric element 21 is different from the above embodiments, and other configurations are the same as those of the above embodiments.

The reinforcing plate main body 51 of the present embodiment has a substantially rectangular frame-shaped contour portion 511 along the entire outer periphery of the piezoelectric element 21 in plan view. The reinforcing plate main body 51 is left through the contour portion 511, and one opening 51 </ b> A is formed inside the contour portion 511.
Even if the vibration energy density distribution is changed from the vibration energy density distribution in the piezoelectric vibrator 50A alone due to the reaction force of the rotor 25 (FIG. 2) with which the protrusion 33 abuts, the opening 51A is distorted by longitudinal vibration. A part of the maximum line segment A and locations in the vicinity of the points B1 and B2 where the distortion caused by the bending vibration is maximum (points B1 ′ and B2 ′ where the distortion caused by the bending vibration is substantially maximum) are included. Is formed. That is, the opening 51A serves as both the first and third cutouts. Since the piezoelectric element 21 freely expands and contracts in the opening 51A, the amplitude can be expanded by the maximum vibration energy that can be generated by the longitudinal vibration and bending vibration of the piezoelectric element 21.
Note that the points (locations) B1 and B2 at which the distortion caused by the bending vibration is maximum are on the contour portion 511. The opening 51A is formed symmetrically about the center line Y.
Here, the width of the opening 51A is preferably 40% to 78%, more preferably 50% to 60% of the width of the reinforcing plate body 51, and the length of the opening 51A is preferably the reinforcing plate body 51. 40% to 80% of the length, and more preferably 50% to 60%.

In the piezoelectric vibrating body 50A of the present embodiment, in substantially the same manner as in the second embodiment, a part of the line segment A where the distortion caused by the longitudinal vibration becomes maximum and the point B1 ′ where the distortion caused by the bending vibration becomes substantially maximum. , B2 ′ and the reinforcing plate main body 51 is opened, so that the same effects as those of the second embodiment can be obtained. In addition, according to the present embodiment, the following effects can be obtained.
(6) Since the contour portion 511 is formed, the member strength of the reinforcing plate body 51 is improved, and the torsional strength in the in-plane direction can be increased.

(7) Further, by having the contour portion 511 along the outer peripheral portion of the piezoelectric element 21, the position of the reinforcing plate 5A when the piezoelectric element 21 and the reinforcing plate 5A are laminated in the manufacturing process of the piezoelectric vibrating body 50A. It becomes easy to align the position of the piezoelectric element 21. That is, the productivity of the piezoelectric vibrating body 50A can be improved, and variations in characteristics can be suppressed.

(8) One opening 51A in which the through hole and the through hole are communicated as described above is formed, and the portion of the opening 51A is largely opened, so that the displacement of the piezoelectric element 21 can be prevented as much as possible. .

[Modification of Fourth Embodiment]
FIG. 19 shows an example in which members 35 made of resin or solder are arranged and fixed in the inner space of the opening 51A ′ formed inside the contour portion 511 ′ of the reinforcing plate body 51, respectively. Since the member 35 has an elastic modulus smaller than that of the reinforcing plate 5A, the member 35 has the same effect as the above-described configuration (FIG. 18) in which the inside of the opening 51A is a space, and the opening 51A ′ is formed to be large in this way. Even if it is made, the intensity | strength of the reinforcement board main body 51 can be more fully ensured by the member 35 being arrange | positioned. For this reason, the length of the opening 51A ′ is longer than the length of the opening 51A in FIG. 18, and the piezoelectric element 21 can freely expand and contract in the wide opening 51A ′, so that the vibration efficiency can be improved.
The member 35 may have an opening corresponding to a portion where the longitudinal vibration node and the bending vibration node overlap each other (the plane center of the piezoelectric element 21).
Moreover, in the said 4th Embodiment, although the outline part 511 was provided along the outer periphery perimeter of the piezoelectric element 21, since the said frame | skeleton is comprised also when a part of outline part 511 is parted, Such a configuration may be used.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described. In the present embodiment, a configuration capable of expanding the amplitudes of longitudinal vibration and bending vibration is shown.
FIG. 20 shows a piezoelectric vibrating body 55A of the present embodiment. In the present embodiment, only the shape of the reinforcing plate main body 56 laminated on the piezoelectric element 21 is different from the above-described embodiments, and other configurations are the same as those of the above-described embodiments.

The reinforcing plate main body 56 of the present embodiment is formed so as to connect a substantially rectangular contour portion 511 and the long side portions 511A and 511B of the contour portion 511 along the width direction of the piezoelectric element 21. The connecting portions 561 to 564 are formed in a substantially ladder shape. Two connecting portions 561 to 564 are provided on each side of the straight line XX that bisects the length of the piezoelectric element 21.
In such a reinforcing plate main body 56, each of the through hole 56 </ b> A and the bored holes 56 </ b> B to 56 </ b> E surrounded by the contour portion 511 and the connecting portions 561 to 564 is formed symmetrically with respect to the center line Y. The through hole 56A is formed to include a portion where the strain generated by the longitudinal vibration is maximized, and functions as a first cut-through portion.
Further, the bore holes 56C and 56D are formed to include points (locations) B1 ′ and B2 ′ at which the strain generated by the bending vibration is substantially maximized, and function as third cutout portions.

Note that each of the through hole 56A and the bored holes 56B to 56E receives a reaction force of the rotor 25 (FIG. 2) with which the protrusion 33 abuts, so that the vibration energy density distribution is determined from the vibration energy density distribution in the piezoelectric vibrator 55A alone. The shape, position and dimensions are determined taking into account the change.
The length L2 of each of the through holes 56B to 56E and the through hole 56A is 15% or less (preferably 5% or more) of the length of the piezoelectric element 21, and the through holes 56B to 56E and The width W2 of each through hole 56A is 78% or less (preferably 40% or more) of the width of the piezoelectric element 21.
In these through holes 56A and bored holes 56B to 56E, the piezoelectric element 21 expands and contracts freely, so that the amplitude can be expanded by the maximum vibration energy that can be generated by the longitudinal vibration and bending vibration of the piezoelectric element 21.

In the piezoelectric vibrating body 55A of the present embodiment, almost the same as in the fourth embodiment, a part of the line segment A where the distortion caused by the longitudinal vibration is maximum, and the point B1 ′ where the distortion caused by the bending vibration is substantially maximum. , B2 ′, the effect is substantially the same as in the third embodiment.
(9) In addition, the long side portions 511A and 511B of the contour portion 511 serve as struts, and the long side portions 511A and 511B and the connecting portions 561 to 564 form a skeleton. The displacement in the out-of-plane direction can be well controlled. As a result, it is possible to reliably increase the amplitude and further improve the vibration efficiency.

(10) Each of the bore holes 56B to 56E and the through hole 56A has a length of 15% or less (preferably 5% or more) and a width of 78% or less (preferably 40% or more) with respect to the dimension of the piezoelectric element 21. Therefore, the displacement of the piezoelectric element 21 in the out-of-plane direction by the reinforcing plate body 56 can be reliably regulated.

  As a modification of the present embodiment, a member other than the reinforcing plate 30 may be disposed in all or any of the through holes 56A and the through holes 56B to 56E.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described.
The piezoelectric vibrating body in the present embodiment is different from the above embodiments in the shape of the protrusions that are in contact with the driven body. In the present embodiment, a configuration in which the amplitudes of longitudinal vibration and bending vibration can be enlarged is shown.
FIG. 21 shows the piezoelectric actuator 80 incorporated in the date display device 8. In the piezoelectric actuator 80, a single electrode 230 that is not divided is formed on each of the piezoelectric elements 21 on the front and back sides of the reinforcing plate 810, and a voltage is applied between the electrode 230 and the reinforcing plate 810. The
FIG. 22 shows the shape of the reinforcing plate 810 in the piezoelectric vibrating body 80A. The reinforcing plate 810 includes substantially the same reinforcing plate main body 81 as that of the second embodiment (FIG. 10), a support portion 82 provided continuously to the side portion on the long side of the reinforcing plate main body 81, and a short of the reinforcing plate main body 81. Protrusions 83 and 84 provided on the sides are provided. The shape positions of the through hole 310 and the through holes 411 to 414 in FIG. 22 are the same as the shape positions of the through hole 310 and the through holes 411 to 414 in FIG. The cut-through holes 411 to 414 serve as second cut-through portions.
Here, the protrusions 83 and 84 are arranged at positions separated from the center line Y in opposite directions, and bending vibration is induced by a moment generated by weight imbalance due to the position of the protrusions 83 and 84. As a result, the piezoelectric vibrator 80A excites longitudinal vibration and bending vibration. Then, the rotor 78 (FIG. 21) is driven in a predetermined direction by the elliptical locus R1 drawn by the protrusion 83.
According to the above-described embodiment, there are substantially the same effects as in the second embodiment.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described. In the present embodiment, a configuration capable of mainly expanding the amplitude of bending vibration is shown.
FIG. 23 shows a piezoelectric vibrating body 60A of the present embodiment. In the present embodiment, only the shape of the reinforcing plate main body 61 laminated on the piezoelectric element 21 is different from those of the above-described embodiments, and other configurations are the same as those of the respective embodiments.

The reinforcing plate body 61 is laminated at the center of the plane of the piezoelectric element 21 and is connected to the support part 32, and the central part 611 extends from one end to the other end in the longitudinal direction of the piezoelectric element 21. The main line part 612 extends and the branch parts 613 are formed so as to intersect the main line part 612.
A total of two branch portions 613 are provided, one each between the one end 612A of the main line portion 612 and the central portion 611 and one between the other end 612B of the main line portion 612 and the central portion 611. A tip portion overlapping the outer edge portion 21 </ b> A of the piezoelectric element 21 of 613 is substantially T-shaped and is fleshed in the longitudinal direction of the piezoelectric element 21.

In such a reinforcing plate main body 61, the outer edge portion along the longitudinal direction of the piezoelectric element 21 is between the two adjacent ones in the one end 612A, the other end 612B, each branch portion 613, and the central portion 611 of the trunk portion 612. It is cut out from the position corresponding to 21A toward the main line part 612, and the cut-through holes 621 to 628 are formed, respectively. These hollow holes 621 to 628 are formed symmetrically about the center line Y.
Further, the through holes 622, 623, 626, 627 are formed including the point B1 or B2 where the strain generated by the bending vibration described above becomes maximum. Accordingly, the cut-through holes 622, 623, 626, and 627 serve as second cut-through portions.

Each of the through holes 621 to 628 is a case where the vibration energy density distribution is changed from the vibration energy density distribution in the piezoelectric vibrating body 60A alone due to the reaction force of the rotor 25 (FIG. 2) with which the protrusion 33 abuts. The shape, position, and dimensions are determined with consideration.
In these through-holes 621 to 628, the piezoelectric element 21 freely expands and contracts, so that the amplitude can be expanded by the maximum vibration energy that can be generated by the bending vibration of the piezoelectric element 21. The piezoelectric vibrating body 60A of the present embodiment does not have an opening in a part of the line segment A where the distortion caused by the longitudinal vibration is maximum, but the piezoelectric element 21 is freely expanded and contracted in the bored holes 621 to 628. Therefore, it can contribute to the expansion of the amplitude of the longitudinal vibration.

The piezoelectric vibrating body 60A of the present embodiment is formed including points B1 and B2 at which distortion caused by flexural vibration is substantially maximum. In addition to the effects (3) and (4), the following There is an effect.
(1 ′) In the piezoelectric actuator 20 that is mounted on the timepiece 1 and operates using a battery as a power source, distortion caused by flexural vibration is based on the consideration on the vibration energy density in the piezoelectric vibrating body 20A as shown in FIGS. Holes 621 to 628 including the maximum points B1 and B2 are formed in the reinforcing plate body 31. In such a through hole 621 to 628, the maximum vibration energy in the piezoelectric element 21 is exerted to increase the amplitude, and the portion other than the through hole 621 to 628 in the reinforcing plate body 31 is out of the plane of the piezoelectric element 21. Since the displacement in the direction is restricted, the amplitude of the bending vibration is surely enlarged.
As a result, the driven body (the rotor 25, the gears 261 and 262, and the chronograph second hand 7A) having a larger load with the same input power, or the driven body is driven at a high speed and compared with the chronograph second hand 7A. The second hand driven at a very high speed can be realized.
On the other hand, even if the input power is reduced, the driven body with a predetermined load can be driven, so that the battery capacity can be reduced and the timepiece 1 can be reduced in size and thickness.

(11) Since the main line portion 612 serves as a support and a skeleton is formed by the main line portion 612, the central portion 611, and the branch portions 613, the displacement of the piezoelectric element 21 in the out-of-plane direction can be well regulated by this skeleton. As a result, the vibration efficiency can be further improved.

[Modification of the seventh embodiment]
FIG. 24 shows an example in which the members 35 formed of resin or solder are disposed and fixed in the through holes 621 ′ to 628 ′ in the reinforcing plate body 61. Since the member 35 has a smaller elastic modulus than the reinforcing plate body 61, the member 35 has the same effect as the above-described configuration (FIG. 23) in which the perforated holes 621 'to 628' are spaces. Even if the perforated holes 621 ′ to 628 ′ are formed and the perforated area in the reinforcing plate main body 61 is large, the strength of the reinforcing plate main body 61 can be more sufficiently ensured by arranging the member 35. For this reason, the front-end | tip part of each branch part 613 'is not made into T shape.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described. This embodiment shows an aspect in which the number of branch portions in the seventh embodiment is increased, and mainly shows a configuration capable of expanding the amplitude of bending vibration.
FIG. 25 shows a piezoelectric vibrating body 65A of the present embodiment. In the present embodiment, only the shape of the reinforcing plate main body 66 laminated on the piezoelectric element 21 is different from the above-described embodiments, and other configurations are the same as those of the above-described embodiments.

The reinforcing plate main body 66 has a central portion 611, a trunk portion 612, and branch portions 663 formed so as to intersect the trunk portion 612, as in the seventh embodiment (FIG. 23). .
Here, a total of six branch portions 663 are provided, one each between the one end 612A of the main line portion 612 and the central portion 611 and three between the other end 612B of the main line portion 612 and the central portion 611. Yes.

In such a reinforcing plate main body 66, the outer edge portion along the longitudinal direction of the piezoelectric element 21 is between the two adjacent ones in the one end 612A, the other end 612B, each branch portion 663, and the central portion 611 of the trunk portion 612. From the position corresponding to 21A, it cuts out toward the trunk line part 612, and the cut-through hole 671-682 is formed by this, respectively. These through-holes 671 to 682 are formed symmetrically about the center line Y.
Further, the through-holes 672 and 678 are formed including the point B1 where the strain generated by the bending vibration is maximum, and the through-holes 675 and 681 are formed including the point B2 where the strain generated by the bending vibration is maximum. Has been. Therefore, the cut-through holes 672, 678, 675, 681 are second cut-through portions.

Each of the through holes 671 to 682 is a case where the vibration energy density distribution is changed from the vibration energy density distribution in the piezoelectric vibrating body 65A alone due to the reaction force of the rotor 25 (FIG. 2) with which the protrusion 33 abuts. The shape, position, and dimensions are determined with consideration.
Here, the length L1 of the bore holes 671 to 682 is 7% or less (preferably 3% or more) of the length of the piezoelectric element 21, and the width W1 of the bore holes 671 to 682 is piezoelectric. The width is 39% or less (preferably 10% or more) of the width of the element 21.
In these hollow holes 671 to 682, the piezoelectric element 21 freely expands and contracts, so that the amplitude can be expanded by the maximum vibration energy that can be generated by the bending vibration of the piezoelectric element 21. The piezoelectric vibrating body 65A of the present embodiment does not have an opening in a part of the line segment A where the distortion caused by the longitudinal vibration is maximum, but the piezoelectric element 21 is freely expanded and contracted in the bored holes 671 to 682. Therefore, it can contribute to the expansion of the amplitude of the longitudinal vibration.

According to the present embodiment, in addition to the effects described in the seventh embodiment, the following effects can be obtained. (12) Since the dimension through which the reinforcing plate body 66 is cut is not more than the above ratio, the displacement of the piezoelectric element 21 in the out-of-plane direction can be reliably regulated by the reinforcing plate body 66.

[Ninth Embodiment]
Next, a ninth embodiment of the present invention will be described. Although the piezoelectric vibrating body in each of the embodiments described above is formed line-symmetrically, an example of a piezoelectric vibrating body that is not line-symmetrical will be described in the present embodiment. In the present embodiment, a configuration that can mainly increase the amplitude of bending vibration is shown.
[1. overall structure]
FIG. 26 is a plan view of a watch as a portable device in the present embodiment.
The timepiece of the present embodiment is an analog display type wristwatch (watch) provided with a movement 2 as timekeeping means and a dial 3, hour hand 4, minute hand 5, and second hand 6 as timekeeping information display units.
A substantially rectangular window portion 3A is provided at the 3 o'clock position of the dial plate 3, and printing is performed on the date wheel 74 by rotation of the date wheel 74 provided on the back side of the dial plate 3 from the window portion 3A. The days are displayed sequentially.

  Note that the timepiece is configured as an electronic timepiece (quartz timepiece), and a driving mechanism for the hour hand 4, the minute hand 5, and the second hand 6 is not shown in the figure, but a circuit board incorporating a quartz resonator, a coil, a stator, A stepping motor having a rotor and a driving wheel train are respectively incorporated in the movement 2.

[2. Structure of date display device]
27 is a plan view of the movement 2 as viewed from the side where the dial 3 is provided, and FIG. 28 is a partially enlarged view of FIG. The movement 2 incorporates a date display device 7 for displaying the date from the window 3A (FIG. 26).
The date display device 7 uses a piezoelectric actuator 70 having a piezoelectric vibrating body 70A and a rotor 78 as a drive source, and transmits date driving intermediate wheels 71 and 72 and a date driving wheel 73 that transmit the driving force while decelerating, and a date driving wheel 73. And a date wheel 74 that rotates.
The piezoelectric actuator 70, date driving intermediate wheels 71 and 72, date driving wheel 73 and date dial 74 are provided on the front side (the dial 3 side) of the main plate 75.
On the other hand, on the back side of the base plate 75, a driving wheel train for driving the hour hand 4, the minute hand 5, the second hand 6, and the like, a battery and the like are provided.

The intermediate date wheel 71 is engaged with a rotor pinion 78A above the rotor 78, and the intermediate date wheel 71 rotates in conjunction with the rotation of the rotor 78.
The intermediate date wheel 72 is composed of a large diameter part 721 and a small diameter part 722. The intermediate wheel 71 is meshed with the large diameter portion 721. The small diameter portion 722 has a disk shape slightly smaller in diameter than the large diameter portion 721 and is fixed to the large diameter portion 721 so as to be concentric. A single notch 722A is formed on the outer peripheral surface of the small diameter portion 722.

The date driving wheel 73 is a gear having five teeth, and the rotation shaft 731 is loosely inserted into a hole 75 </ b> A formed in the base plate 75. The hole 75 </ b> A is formed in a long hole shape along the circumferential direction of the date indicator 74. The rotating shaft 731 is urged toward the upper right direction in FIG. Then, as the intermediate date wheel 72 rotates once, the teeth of the intermediate date wheel 73 fit into the notch 722A of the intermediate date wheel 72 and rotates by one tooth, so that the date driving wheel 73 is fed by one tooth. The date displayed from the window 3A (FIG. 26) is changed.
The date indicator driving wheel 73 meshes with the internal teeth 741 of the date indicator 74, and the urging action of the leaf spring 732 prevents the date indicator 74 from swinging.

The date wheel 74 is a ring-shaped gear having numbers “1” to “31” printed on the circumference thereof, and is arranged on the outer peripheral portion of the movement 2.
In such a date display device 7, the piezoelectric actuator 70 operates at the change of day (24:00), the rotor 78, the date turning intermediate wheels 71 and 72 are sequentially rotated, and the date turning wheel 73 is engaged with the notch 722A. Thus, the date wheel 74 rotates for one day.

[3. Structure of piezoelectric actuator]
(Configuration of rotor)
A rotor 78 constituting the piezoelectric actuator 70 is rotatably held by a rotor support 780. The rotor support 780 is formed in a U-shaped cross section sandwiching the front and back of the rotor 78, and is pivotally supported by the ground plane 75 around the pin 781. Further, the rotor support 780 is provided with another pin 782, and a pressing spring 783 as an urging means wound around the shaft 75B of the base plate 75 abuts on this pin 782, whereby in FIG. It is urged clockwise (to the piezoelectric vibrating body 70A side).

(Configuration of piezoelectric vibrator)
As shown in FIG. 28, the piezoelectric vibrating body 70A includes the piezoelectric element 21 similar to that of each of the above embodiments, but as shown in FIG. 29, the shape of the reinforcing plate 79 is different from that of each of the above embodiments.
As shown in FIG. 29, the reinforcing plate main body 790 includes a central portion 611 that is stacked at the center of the plane of the piezoelectric element 21 and that is connected to the support portion 32, and main trunk portions 791 and 792 that extend to both sides of the central portion 611. And branch portions 793 and 794 formed so as to intersect the main line portions 791 and 792, respectively.
The main line portions 791 and 792 are provided point-symmetrically with respect to the plane center of the piezoelectric element 21, and the tip end portions of the branch portions 793 and 794 that overlap the outer edge portion 21A of the piezoelectric element 21 are substantially T-shaped and are piezoelectric. The element 21 is thickened in the longitudinal direction.

In such a reinforcing plate main body 790, bore holes 79 </ b> A to 79 </ b> H that are bored from the position corresponding to the outer edge portion 21 </ b> A along the longitudinal direction of the piezoelectric element 21 toward the main line portions 791 and 792 are formed. . These hollow holes 79 </ b> A to 79 </ b> H are formed point-symmetrically with respect to the plane center of the piezoelectric element 21.
Further, the bore holes 79B and 79F are formed including the point B1 where the strain generated by the bending vibration is maximized, and the bore holes 79C and 79G are the points B2 where the strain caused by the bending vibration is maximized. It is formed including. Therefore, the perforated holes 79B, 79F, 79C, 79G become the second perforated part.

  Each of the through-holes 79A to 79H is a case where the vibration energy density distribution is changed from the vibration energy density distribution in the piezoelectric vibrator 70A alone due to the reaction force of the rotor 25 (FIG. 2) with which the protrusion 33 abuts. The shape, position, and dimensions are determined with consideration.

[4. Action of piezoelectric vibrator]
In the piezoelectric vibrating body 70A of the present embodiment, by applying a potential to the electrodes 231, 233, 235 (FIG. 28) and the reinforcing plate 79, the piezoelectric vibrator 70A vibrates in a mixed mode in which longitudinal vibration and bending vibration are combined, and the protrusions 33 draws an elliptical locus R1 and drives the rotor 78 (FIG. 28) in a predetermined direction. At this time, the electrodes 232 and 234 to which no potential is applied are used as vibration detection electrodes.
Here, since the piezoelectric element 21 expands and contracts freely in the through holes 79 </ b> A to 79 </ b> H, the amplitude can be increased by the maximum vibration energy that can be generated by the bending vibration of the piezoelectric element 21. The piezoelectric vibrating body 60A of the present embodiment does not have an opening in a part of the line segment A where the distortion caused by the longitudinal vibration is maximum, but the piezoelectric element 21 is freely expanded and contracted in the through holes 79A to 79H. Therefore, it can contribute to the expansion of the amplitude of the longitudinal vibration.

According to this embodiment, there are substantially the same effects as those of the seventh embodiment (FIG. 23).
In the present embodiment, a through hole including a part of the line segment A may be formed in the central portion 611.
In this case, there are substantially the same effects as in the third embodiment (FIG. 12).

[Modification of the present invention]
The present invention is not limited to the above-described embodiments, and can be arbitrarily improved and modified without departing from the gist of the present invention.
For example, the configuration shown in FIG. 20 may be modified as shown in FIG. In the configuration of FIG. 30 as well, a part of the line segment A where the distortion caused by the longitudinal vibration becomes maximum and the points B1 ′ and B2 ′ where the distortion caused by the bending vibration becomes substantially maximum are opened. The same effects as those of the fifth embodiment shown in FIG.
Further, a connecting portion may be added to the configuration shown in FIG. By the connecting portions 561 and 564, the torsional strength of the reinforcing plate body 51 is further improved.
Further, in the configuration shown in FIG. 18, both of a part of the line segment A where the distortion caused by the longitudinal vibration becomes maximum and the points B1 ′ and B2 ′ where the distortion caused by the bending vibration become substantially maximum are one opening. Although it was included in 51A, it is not restricted to this, For example, like FIG. 30, some of these line segments A, B1 ', and B2' may be opened separately.
Furthermore, although the support part of the reinforcement board in each said embodiment was formed in the central part vicinity of the long side of a piezoelectric vibrating body, the formation location of a support part is not limited to the said embodiment. For example, the support plate on the reinforcing plate may be formed at a position slightly moved to the short side from the center of the long side of the piezoelectric vibrator, or near the center of the short side of the piezoelectric vibrator. Moreover, the support part of the reinforcement board in each said embodiment may be provided in the width direction both sides of a piezoelectric vibrating body, respectively, or may be provided only in one side. A support portion may be formed on one short side portion of the piezoelectric vibrating body.
As described above, the number of support portions and the formation locations in the reinforcing plate are not limited to the above-described embodiment, and depending on the number of support portions and the formation locations, the longitudinal vibration nodes, the antinodes, the flexural vibration nodes, and the antinodes, respectively. The position may be different from that described above. Even in such a case, in the same manner as described with reference to FIG. 36, FIG. 40, FIG. 41, etc., the portion where the distortion caused by the longitudinal vibration becomes maximum or the distortion caused by the bending vibration becomes maximum. The location can be specified. For example, in flexural vibration, the piezoelectric element or reinforcing plate has a planar shape, vertical / horizontal dimension ratio, driving frequency, number of electrodes formed, electrode arrangement, and the like, from the central point O to the short side of FIG. There may be a plurality of positions corresponding to the point P (a place where the amount of displacement in the piezoelectric vibration body width direction in the bending vibration becomes maximum). In that case, the second punched-out portion or the third punched-out portion is provided at the reinforcing plate position corresponding to the location where the strain caused by the bending vibration is maximized (the location satisfying both the P position and the maximum strained portion (see FIG. 40)). Forming a cut-through portion is also included in the present invention. Also in this case, the effect of the present invention that the vibration efficiency of the piezoelectric vibrator described above can be improved can be exhibited. Then, based on the location where the distortion caused by the longitudinal vibration is maximized or the location where the distortion caused by the bending vibration is maximized, the first cutout portion, the second cutout portion, and the third cutout portion are formed. The

In each of the above-described configurations, the portion where the strain caused by the longitudinal vibration is maximum or the portion where the strain caused by the bending vibration is maximum is the entire amplitude (displacement amount) of the piezoelectric vibrator that is a laminate of the reinforcing plate and the piezoelectric element. ) And strain, and a cut-through portion is formed at the position of the reinforcing plate corresponding to the location where the strain thus identified is maximum. However, not only the amplitude and strain of the entire piezoelectric vibrator, but also the location where the strain caused by longitudinal vibration is maximum or the strain caused by bending vibration is based on the amplitude or strain of the piezoelectric element alone or the reinforcing plate alone May be specified. The amplitude and strain of the piezoelectric element alone and the reinforcing plate alone can be detected by simulating with software, and the detection data is similar to the data in FIG. 36, FIG. 40, FIG. That is, the distortion and amplitude of the piezoelectric element alone and the distortion and amplitude of the reinforcing plate alone show the same tendency as in FIGS. 36, 40, and 41.
Here, in each of the above embodiments, a rectangular piezoelectric element is laminated on the reinforcing plate whose basic shape is not hollowed out, and the width and length of the piezoelectric element and the basic shape of the reinforcing plate are stacked. The widths and lengths of the piezoelectric elements were substantially the same, and the positions of the four sides of the piezoelectric element and the four sides of the basic shape of the reinforcing plate were substantially the same. In addition to such a configuration, the present invention also includes a configuration in which the shape of the piezoelectric element is different from the basic shape of the reinforcing plate, and a configuration in which the vertical and horizontal dimensions of the piezoelectric element are different from the vertical and horizontal dimensions of the reference shape of the reinforcing plate. It is.
That is, according to the present invention, the width dimension of the rectangular piezoelectric element is different from the width dimension of the reinforcing plate whose basic shape is rectangular, the position of the outer edge along the long side of the piezoelectric element, A configuration in which the position of the outer edge portion along the long side of the basic shape does not match is also included. Even in such a configuration, as described above, based on the amplitude / strain of the entire piezoelectric vibrator or the amplitude / strain of the piezoelectric element alone, the location where the strain caused by the longitudinal vibration is maximum or the strain caused by the flexural vibration is the maximum. Therefore, it is only necessary that a cut-through portion is formed at the position of the reinforcing plate corresponding to the location where the strain specified in this way is maximum.
For example, when the width of the basic shape of the reinforcing plate is narrower than the width of the piezoelectric element and the portion where the distortion caused by the bending vibration of the piezoelectric vibrating body is maximum is located further outside the outer edge portion of the reinforcing plate, the second If the cut-through portion or the third cut-through portion is cut inward from the outer edge portion of the reinforcing plate positioned inward in the width direction from the location where the distortion caused by bending vibration is maximum, the inner side in the width direction. Good. Further, the basic shape of the reinforcing plate is wider than the width of the piezoelectric element, and the formation portion of the cut-through portion is specified based on the amplitude and strain of the piezoelectric element alone, and the bending vibration of the piezoelectric element alone is When the portion where the generated strain is maximum is located inside the outer edge of the reinforcing plate, the second cut-out portion or the third cut-out portion is located outside in the width direction from the portion where the strain generated by bending vibration is maximum. It suffices if the reinforcing plate is spaced from the outer edge of the reinforcing plate so as to penetrate inward in the width direction.

In each of the embodiments described above, the piezoelectric vibrating body having a rectangular shape in plan view is shown. However, the shape of the piezoelectric vibrating body is not limited to this, and a longitudinal vibration or a bending vibration such as a trapezoid, a parallelogram, and a rhombus is excited. Various shapes can be employed.
Further, in the piezoelectric vibrating body in each of the embodiments, the piezoelectric elements are laminated one by one on the front and back of the reinforcing plate, but not limited to this, a plurality of piezoelectric elements are laminated on each of the front and back of the reinforcing plate, Piezoelectric elements may be laminated only on one side of the reinforcing plate.
The electrode arrangement for driving the piezoelectric element and the shape thereof are not limited to those described above, and can be appropriately selected depending on the situation. For example, in the first embodiment and the like, the electrode formed on the piezoelectric element is divided into five parts. However, the present invention is not limited to this, and a rectangular piezoelectric element may be formed with four electrodes vertically and horizontally. The number of electrodes formed on the piezoelectric element is arbitrary, and may be three or less, four, five, six or more. When piezoelectric elements are stacked on the front and back surfaces of the reinforcing plate, the number and shape of electrodes formed on the front-side piezoelectric element are the same as the number and shape of electrodes formed on the back-side piezoelectric element. Or different.
The piezoelectric vibrators shown in FIG. 23 to FIG. 25 and FIG. 29 mainly excite bending vibration, and the mode (position, shape, number) of electrodes formed on the piezoelectric elements of these piezoelectric vibrators. The frequency of the driving signal (applied voltage) and the like are appropriately determined so as to increase the amplitude of the bending vibration.

  In each of the above embodiments, the driven body is driven by transmitting the vibration of the piezoelectric vibrating body to the rotor. However, the present invention is not limited to this. For example, the vibration of the piezoelectric vibrating body is transmitted in a straight line. The drive body to drive may be sufficient. For example, the linearly driven drive body may be provided on a slider or guided by a plurality of rollers.

In each of the above-described embodiments, a wristwatch is illustrated as an example of application of the piezoelectric vibrator. In these various timepieces, for example, it can be used as a mechanism for driving a Karakuri doll or the like.
In addition to the watch, the piezoelectric vibrator of the present invention is also used as appropriate for camera zoom and autofocus mechanisms, film winding mechanisms, printer paper feed mechanisms, and mechanisms for driving vehicles and toys such as dolls. it can. The piezoelectric vibrating body of the present invention can be widely used in various electronic devices such as a timepiece, a camera, a printer, a toy, and a portable information terminal and a telephone.

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

1 is an external view of a wristwatch according to a first embodiment of the present invention. The perspective view of the piezoelectric actuator unit in the said embodiment. The perspective view of the piezoelectric vibrating body in the said embodiment. The top view of the reinforcement board in the said embodiment. The figure which shows the electrical connection of the piezoelectric vibrating body in the said embodiment. The graph which shows the relationship between the drive frequency and impedance in the piezoelectric vibrating body in the said embodiment. The figure which shows operation | movement of the piezoelectric vibrating body in the said embodiment. The figure which shows the modification of the said 1st Embodiment. The figure which shows the other modification of the said 1st Embodiment. The top view of the piezoelectric vibrating body in 2nd Embodiment of this invention. The figure which shows the modification of the said 2nd Embodiment. The top view of the piezoelectric vibrating body in 3rd Embodiment of this invention. The figure which shows the reinforcement board in the said embodiment. The figure which shows the piezoelectric vibrating body of this embodiment provided with the reinforcement board of FIG. The figure which shows the vibration behavior of the said piezoelectric vibrating body. The figure which showed only the piezoelectric element in the said piezoelectric vibrating body at the time of a vibration. The figure which shows the vibration amplitude of the piezoelectric vibrating body of this embodiment, and the vibration amplitude of the piezoelectric vibrating body in which the penetration part is not formed in the reinforcement board, respectively. The top view of the piezoelectric vibrating body in 4th Embodiment of this invention. The figure which shows the modification of the said 4th Embodiment. The top view of the piezoelectric vibrating body in 5th Embodiment of this invention. The top view of the date display apparatus in 6th Embodiment of this invention. The top view of the reinforcement board in the said embodiment. The top view of the piezoelectric vibrating body in 7th Embodiment of this invention. The figure which shows the modification of 7th Embodiment of this invention. The top view of the piezoelectric vibrating body in 8th Embodiment of this invention. The external view of the wristwatch in 9th Embodiment of this invention. The top view of the date display apparatus in the said embodiment. The elements on larger scale of FIG. The top view of the reinforcement board in the said embodiment. The top view of the reinforcement board in the modification of this invention. The top view of the reinforcement board in the modification of this invention. The figure which shows the reinforcement board of an area considerably smaller than the area of a piezoelectric element. The figure which shows the piezoelectric vibrating body which has a reinforcement board of FIG. FIG. 33 is a diagram in which the tendency of displacement in the out-of-plane direction is analyzed in the piezoelectric vibrator having the reinforcing plate of FIG. The figure which showed only the piezoelectric element in the said piezoelectric vibrating body at the time of a vibration. The figure which shows the magnitude | size of the distortion produced by a longitudinal vibration. The figure which shows the distance normalized to 100 in each of FIG. 36 and FIG. The figure which shows the position of the detection electrode formed in the said piezoelectric vibrating body. The figure which shows the aspect which drives a to-be-driven body by a longitudinal vibration. The figure which shows the magnitude | size of the distortion produced by bending vibration. The figure which shows the behavior of a bending vibration. The figure which shows the aspect which drives a to-be-driven body by bending vibration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Timepiece (mobile device), 20 ... Piezoelectric actuator, 20A ... Piezoelectric vibrator, 21 ... Piezoelectric element, 21A ... Outer edge part, 25 ... Rotor (driven body), 30 ... Reinforcing plate, 31 ... Reinforcing plate body, 32 ... Supporting portion, 33, 34, 911, 931 ... Protruding portion (contacting portion), 35 ... Member (low elastic modulus) Member), 40A ... piezoelectric vibrating body, 41 ... reinforcing plate main body, 45A ... piezoelectric vibrating body, 46 ... reinforcing plate main body, 50A ... piezoelectric vibrating body, 5A ... reinforcing plate, 51... Reinforcing plate main body, 51 A... Opening (also serving as the first cut-out portion and the third cut-through portion), 55 A... Piezoelectric vibrator, 56. Through-hole (first cut-through portion), 56C, 56D ... hollow-through hole (third cut-through portion), 60A ... Electromagnetic vibrator 61... Reinforcing plate main body, 65 A... Piezoelectric vibrating body, 66... Reinforcing plate main body, 70 ... Piezoelectric actuator, 70 A ... Piezoelectric vibrator, 79 A to 79 H. Through hole, 79... Reinforcing plate, 80... Piezoelectric actuator, 80 A... Piezoelectric vibrating body, 81. ... Piezoelectric vibrator, 92 ... Rotor (driven body), 93 ... Piezoelectric vibrator, 310 ... Through hole (first through-hole), 350 ... Through hole, 411-414 ... Drilling hole (second penetration part), 461 ... Center part, 462 ... Main line part, 462A ... One end, 462B ... Other end, 463 ... Branch part, 471- 482 ... bore hole, 511A, 511B ... long side part, 511 ... contour part, 61-564 ... connection part, 611 ... center part, 612 ... trunk line part, 612 A ... one end, 612 B ... other end, 613 ... branch part, 621-628 ... chestnut Through-hole, 663 ... branch, 671-682 ... hollow through-hole, 790 ... reinforcing plate body, 791,792 ... main line, 793,794 ... branch, 810 ... Reinforcing plate, A ... line segment (location) where strain caused by longitudinal vibration is maximum, B1, B2 ... point (location) where strain caused by bending vibration is maximum, B1 ', B2' ... Points (locations) at which distortion caused by flexural vibration is substantially maximum, L1, L2... Length, W1, W2... Width, Y.

Claims (9)

A piezoelectric vibrating body comprising a piezoelectric element and a reinforcing plate on which the piezoelectric element is laminated and fixed, wherein a mixed vibration mode in which bending vibration is added to longitudinal vibration is excited,
In the reinforcing plate,
A first cut-out portion that opens including a center portion of the piezoelectric vibrator or the reinforcing plate generated by the longitudinal vibration or a portion where the distortion of the piezoelectric element is maximized ;
The piezoelectric vibrator or the reinforcing plate generated by the flexural vibration or the second punched-out portion is formed so as to include a portion where the distortion of the piezoelectric element is maximized ;
The contact area between the reinforcing plate and said piezoelectric element, a piezoelectric vibrator, characterized in that less than the area of the piezoelectric element by the formation of the first void part. The piezoelectric vibrating body according to claim 1 ,
The reinforcing plate includes a central portion in which the first cut-out portion is formed, and a trunk portion extending through the central portion between one end portion and the other end portion of the piezoelectric element in the vibration direction of the longitudinal vibration. One or more branch portions formed so as to intersect the main line portion between one end portion of the main line portion and the central portion and between the other end portion of the main line portion and the central portion. And having
In the region adjacent to the main line part and the branch part, the second cut-out part cut from the outer edge part of the reinforcing plate toward the main line part is formed. body. In the piezoelectric vibrating body according to claim 1 or 2 ,
The reinforcing plate has a substantially rectangular outer shape in plan view when not hollowed out,
At least one of the cut-through portions is formed in line symmetry with respect to a center line that bisects the width of the reinforcing plate. In the piezoelectric vibrating body according to any one of claims 1 to 3 ,
A member made of a material having a smaller elastic modulus than the material of the reinforcing plate is disposed in at least one of the cut-through portions. In the piezoelectric vibrating body according to any one of claims 1 to 4 ,
The reinforcing plate has an abutting portion that abuts on the driven body and drives the driven body,
The first cut-out portion is formed so as to include a portion where the distortion generated by the longitudinal vibration is maximum or substantially maximum in a state where the piezoelectric vibration body receives a reaction force of the driven body. A piezoelectric vibrator characterized by the above. In the piezoelectric vibrating body according to any one of claims 1 to 5 ,
The reinforcing plate has an abutting portion that abuts on the driven body and drives the driven body,
The second cut-out portion is formed so as to include a portion where the distortion generated by the bending vibration is maximum or substantially maximum in a state where the piezoelectric vibration body receives a reaction force of the driven body. A piezoelectric vibrator characterized by the above. The piezoelectric vibrating body according to any one of claims 1 to 6 ,
A piezoelectric actuator, comprising: a driven body that is driven by vibration transmitted from the piezoelectric vibrating body. A portable device comprising the piezoelectric actuator according to claim 7 . The portable device according to claim 8 is a timepiece including a timing unit and a timing information display unit that displays information measured by the timing unit, and the timing information display unit is driven by the driven body. A portable device characterized by

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