JP4392076B2 - Ultrasonic motor and electronic equipment with ultrasonic motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic motor and an electronic apparatus with an ultrasonic motor using the same, and more particularly to an ultrasonic motor whose output does not depend on a driving direction and an electronic apparatus with an ultrasonic motor using the same.
[0002]
[Prior art]
Recently, in the field of micromechanics, an ultrasonic motor using an elliptical motion as a combined vibration of a stretching vibration and a bending vibration generated in a piezoelectric body to which a drive signal such as an alternating voltage is applied has been attracting attention. .
Among the ultrasonic motors, there is an ultrasonic motor of a type that reverses the driving direction by changing a polarization unit that inputs a driving signal.
[0003]
As this type of ultrasonic motor, for example, there is a disk-type ultrasonic motor 100 shown in FIG. 9, FIG. 10, and FIG.
As shown in the schematic diagram of the side surface direction of FIG. 9, the ultrasonic motor 100 includes a piezoelectric element 101, a vibrating body 102 that is laminated on the piezoelectric element and amplifies vibration of the piezoelectric element 101, and a plurality of protrusions 103. And the rotor 104 that rotates in accordance with the vibration transmitted from the protrusion 103.
[0004]
The piezoelectric element 101 is formed by forming a well-known piezoelectric body into a disk shape and providing a hole 101c through which a rotation shaft passes at the center. The piezoelectric element 101 is divided into six in the circumferential direction, and the polarization directions are staggered. It is polarized so that each divided portion is further divided into two equal parts. As a result, as shown in the schematic top views of FIGS. 9 and 10, the polarization portions 101 a and 101 b polarized in opposite polarities are alternately arranged every two.
[0005]
Here, as shown in FIG. 10, every other protrusion 103 is provided at the boundary of the polarization portion.
In addition, the piezoelectric element 101 is provided with electrodes 105a and 105b as electrodes for inputting drive signals. The electrode 105a covers every other polarization part, and the electrode 105b covers every other polarization part so as to be alternated with the electrode 105a.
[0006]
Here, a part of the electrode 105a is provided around the inner edge of the piezoelectric element 101 to connect the electrodes on each polarization part to form one electrode, and a part of the electrode 105b By providing the entire periphery of the outer edge of the piezoelectric element 101, the electrodes on each polarization part are connected to form another electrode.
That is, when a drive signal is input to the electrode 105b, a standing wave is generated in the piezoelectric element 101 with the central portion of each polarization portion covered by the electrode 105b as an antinode. When a standing wave is generated, the protrusions 103 are located every other halfway between the antinodes and nodes of the standing wave, so that the heads of all the protrusions 103 swing in one direction. For this reason, the rotor 104 in contact with the protrusion 103 rotates in one direction as shown in FIG.
[0007]
In addition, when a drive signal is input to the electrode 105a, a standing wave is generated in the piezoelectric element 101 with the center of each polarization portion covered by the electrode 105a as the antinode. The part swings in the opposite direction to that when a drive signal is input to the electrode 105b. Therefore, in this case, as shown in FIG. 11B, the rotor 104 in contact with the protrusion 103 rotates in the opposite direction to that when a drive signal is input to the electrode 105b.
[0008]
[Problems to be solved by the invention]
Generally, it is desirable that the magnitude of the driving force generated in the motor by the driving signal having the same magnitude is the same value regardless of the driving direction.
However, in the ultrasonic motor 100, as described above, the electrode 105a covers the entire inner edge of the piezoelectric element 101 in addition to covering the predetermined polarization portion, and the electrode 105b includes the predetermined polarization portion. In addition to covering, the entire outer edge of the piezoelectric element 101 is covered. That is, the area, that is, impedance, of the electrodes 105a and 105b was different.
[0009]
Therefore, in the ultrasonic motor 100, the magnitude of the driving force generated by the same magnitude of the driving signal differs depending on the driving direction.
This problem is not limited to the ultrasonic motor 100, and is a general problem in an ultrasonic motor that reverses the driving direction by changing the polarization unit that inputs the driving signal.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic motor that is of a type that reverses the driving direction by changing the polarization part that inputs the driving signal, and that suppresses the driving direction dependency of the driving force.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, the inventions described in claim 1 and claim 2
A disc-shaped vibrating body, and a plurality of protrusions provided on the upper surface of the vibrating body;
An ultrasonic motor having a disk-shaped piezoelectric element fixed to a lower surface of a vibrating body and a rotor that rotates by vibration of the protrusion, the piezoelectric element having electrodes divided in a circumferential direction, An electrode that short-circuits every other divided electrode at the inner edge of the piezoelectric element, and one electrode that is not short-circuited at the inner edge of the piezoelectric element among the divided electrodes, at the outer edge of the piezoelectric element An electrode that is short-circuited every other;
The width (thickness in claim 2) of the electrodes that short-circuit every other divided electrode at the outer edge of the piezoelectric element is equal to every other divided electrode at the inner edge of the piezoelectric element. It is characterized by being thicker (thick in claim 2) than the width of the electrode (thick in claim 2) .
[0012]
According to the first and second aspects of the invention, the impedance of the electrodes that short-circuit every other divided electrode at the outer edge of the piezoelectric element is divided at the inner edge of the piezoelectric element. In order to approach the impedance of an electrode that short-circuits every other electrode, the driving force in the reverse direction of the ultrasonic motor matches the driving force when driven in the forward direction using the same driving signal.
[0013]
Therefore, an ultrasonic motor capable of obtaining a constant driving force regardless of the driving direction can be produced.
Further, the invention described in claims 3 and 4 is a rectangular parallelepiped piezoelectric element and four divided by dividing one surface of the piezoelectric element into two equal parts in the vertical direction and two in the horizontal direction. Four electrodes provided in each region, an electrode for short-circuiting a pair of diagonal electrodes among the four electrodes at the central portion of the piezoelectric element, and a central portion of the piezoelectric element among the four electrodes An electrode that short-circuits two electrodes that are not short-circuited at the outer peripheral edge of the piezoelectric element, and the width (thickness in claim 4) of the electrode that is short-circuited at the outer peripheral edge of the piezoelectric element is the center of the piezoelectric element It is characterized by being thicker (thick in claim 4) than the width (thick in claim 4) of the electrode that is short-circuited at the portion.
[0014]
According to the third and fourth aspects of the present invention, the impedance of the electrode that short-circuits a pair of electrodes on the diagonal line among the four electrodes at the central portion of the piezoelectric element is determined by the four electrodes. In order to bring the two electrodes that are not short-circuited at the center of the piezoelectric element closer to the impedance of the electrode that is short-circuited at the outer peripheral edge of the piezoelectric element, the driving force in the reverse direction of the ultrasonic motor uses the same drive signal. This corresponds to the driving force when driven in the positive direction.
[0015]
The invention according to claim 5 is an electronic apparatus with an ultrasonic motor having the ultrasonic motor according to any one of claims 1 to 4 .
[0016]
According to the fifth aspect of the present invention, even if the built-in output mechanism is driven in the reverse direction, the output mechanism is driven by the same amount as when it is driven in the forward direction using the same drive signal. To do.
Therefore, since a constant drive amount can be obtained regardless of the drive direction, an electronic apparatus with an ultrasonic motor that can easily control the drive amount can be manufactured.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an ultrasonic motor and an electronic apparatus with an ultrasonic motor to which the present invention is applied will be described in detail with reference to the drawings.
<First embodiment>
First, the ultrasonic motor 1 which is the 1st Example of this invention is demonstrated using FIG.
[0018]
FIG. 1A is a schematic top view illustrating a vibrating body 12 and a protrusion 13 that are components of the ultrasonic motor 1, and FIG. 1B is a piezoelectric element that is a component of the ultrasonic motor 1. 11 is a schematic top view of the piezoelectric element 11, and FIG.
First, the configuration of the ultrasonic motor 1 will be described.
[0019]
The ultrasonic motor 1 includes a disk-shaped piezoelectric element 11, a disk-shaped vibrating body 12 fixed to the upper surface of the piezoelectric element 11, a plurality of protrusions 13 integrally provided on the upper surface of the vibrating body 12, The rotor 104 that rotates in response to vibration transmitted from the protrusion 13, the electrode 15 that floats the potential of the upper surface of the piezoelectric element 11, and the electrode 16 that inputs a drive signal to the lower surface of the piezoelectric element 11 (second) Electrode) and electrode 17 (first electrode). The positional relationship between these components is the same as that of the ultrasonic motor 100 schematically shown in FIG.
[0020]
The piezoelectric element 11 has the same configuration as the piezoelectric element 101, and is formed by forming a well-known piezoelectric body such as barium titanate or lead titanate into a disk shape and providing a hole 11c through which a rotation shaft passes. Dividing into six parts in the circumferential direction, the divided parts are polarized so that the polarization directions are staggered, and each divided part is further divided into two equal parts. Accordingly, a configuration is adopted in which polarization portions 11a (forward polarization portions) and polarization portions 11b (reverse polarization portions) polarized in opposite polarities are alternately arranged every two.
[0021]
The vibrating body 12 has the same configuration as the vibrating body 102 and is formed by molding a rigid body such as a metal into a disk shape, and amplifies the vibration of the piezoelectric element 11.
Further, as shown in FIGS. 1A and 1C, every other protrusion 13 is provided at a location corresponding to the boundary of each polarization portion of the piezoelectric element 11. The height of the protrusion 13 is adjusted so as to contact the rotor 104.
[0022]
The rotor 104 is obtained by processing a rigid body into a disk shape, and rotates according to the operation of the protrusion 13.
The electrode 15 covers almost the entire top surface of the piezoelectric element 11, and its potential is floating.
The electrode 16 is provided on the lower surface of the piezoelectric element 11 and covers every other polarized portion of the piezoelectric element 11 (second polarized portion).
[0023]
Further, a part of the electrode 16 is provided around the entire inner edge of the piezoelectric element 11 to form a connection line 16a, thereby forming one electrode.
The electrodes 17 are provided on the lower surface of the piezoelectric element 11 and cover every other polarization part (first polarization part) of the piezoelectric element 11 so as to be alternated with the electrode 16.
The electrode 17 forms one electrode by providing a portion on the outer edge entire periphery of the piezoelectric element 11 and the connection line 17a.
Here, the connection line 17a is formed thicker than the connection line 16a. The thickness is set so that the impedance of the electrode 16 and the impedance of the electrode 17 are approximately the same.
[0024]
Therefore, although the total length of the connection line 17a is longer than the total length of the connection line 16a, the difference between the impedance of the electrode 16 and the impedance of the electrode 17 is eliminated.
Next, the operation of the ultrasonic motor 1 will be described.
First, when a drive signal is input to the electrode 16, a standing wave is generated in the piezoelectric element 11 with the central portion of each polarization portion covered by the electrode 16 as an antinode. Every other protrusion 13 is located between the antinodes and nodes of this standing wave. Therefore, the heads of all the protrusions 13 swing in one direction. For this reason, the rotor 104 in contact with the protrusion 13 rotates in one direction.
[0025]
When a drive signal is input to the electrode 17, a standing wave is generated in the piezoelectric element 11 with the central portion of each polarization portion covered by the electrode 16 as a node. The part swings in the other direction when a drive signal is input to the electrode 16. Accordingly, in this case, the rotor 104 in contact with the head of the protrusion 13 rotates in the direction opposite to that when the drive signal is input to the electrode 16.
[0026]
Here, as described above, the magnitude of the impedance of the electrode 16 and the magnitude of the impedance of the electrode 17 are the same. Therefore, when the same driving signal is input, the rotational force of the rotor 104, that is, the driving force of the ultrasonic motor 1 is constant regardless of the rotational direction.
As described above, in the ultrasonic motor 1 according to the first embodiment of the present invention, the thickness of the connection line 17a that connects every other electrode of the polarization portion along the outer edge portion to be the electrode 17 is set to the electrode 17. In other words, every other electrode of the polarization part is connected along the inner edge so as to be thinner than the thickness of the connection line 16a used as the electrode 16, so that the connection line 17a is longer than the connection line 16a. Instead, the impedance of the electrode 17 can be matched with the impedance of the electrode 16.
[0027]
Therefore, according to the ultrasonic motor 1, even if a driving signal is input to the electrode 17 and the rotor 104 is rotated in the reverse direction, the rotational force, that is, the driving force of the ultrasonic motor 1 is input to the electrode 16. This is the same as when the rotor 104 is rotated in the forward direction.
<Second embodiment>
Next, the ultrasonic motor 2 which is the 2nd Example of this invention is demonstrated using FIG.
[0028]
2A is a schematic diagram illustrating the configuration of the electrode 16 and the electrode 21 provided on the lower surface of the piezoelectric element 11 in the ultrasonic motor 2, and FIG. 2B is an X-axis of FIG. It is the cross-sectional schematic in X-ray | X_line.
The ultrasonic motor 2 has substantially the same configuration as the ultrasonic motor 1, but uses an electrode 21 (first electrode) instead of the electrode 17.
[0029]
The electrode 21 has substantially the same configuration as the electrode 17, but uses a connection line 21a instead of the connection line 17a.
That is, as shown in FIG. 2B, the connection line 21a has substantially the same thickness as the connection line 16a, but the impedance is made smaller than that of the connection line 16a by making the thickness thicker than the connection line 16a. It becomes composition.
[0030]
Here, the connection line 21a is deposited thicker than the connection line 16a by repeating the same manufacturing process several times, or by extending the deposition time in the case of a thin film deposition method such as a vacuum process.
Therefore, according to this ultrasonic motor 2, by increasing the thickness of the connection line 21 a, the same effect as that of increasing the width of the connection line 17 a in the ultrasonic motor 1 can be obtained. Similar effects can be obtained.
[0031]
<Third embodiment>
Next, an ultrasonic motor 3 according to a third embodiment of the present invention will be described with reference to FIGS. 3, 4, 5, 6 and 7.
FIG. 3 is a schematic perspective view of the ultrasonic motor 3. FIG. 4 is a schematic top view of a piezoelectric body 33 that is a component of the ultrasonic motor 3, and FIG. 5 is a schematic bottom view of the piezoelectric body 33. FIG. 6 is a schematic bottom view of the piezoelectric body 34 that is one component of the ultrasonic motor 3. FIG. 7A is a diagram illustrating a case where the rotor 32 which is one component of the ultrasonic motor 3 rotates in one direction, and FIG. 7B illustrates a case where the rotor 32 rotates in the reverse direction. It is a figure to do.
[0032]
First, the configuration of the ultrasonic motor 3 will be described.
As shown in FIG. 3, the ultrasonic motor 3 includes a piezoelectric element 31 that is a rectangular parallelepiped, a rotor 32 that is in contact with the vicinity of the center of one end surface of the piezoelectric element 31, and an electrode 35 (first electrode). , An electrode 36 (second electrode), an electrode 37, and an electrode 38.
[0033]
As shown in FIG. 3, the piezoelectric element 31 is obtained by integrally laminating a piezoelectric body 33 (first piezoelectric body) on a piezoelectric body 34 (second piezoelectric body).
The piezoelectric body 33 is formed by forming a known piezoelectric body such as barium titanate or lead titanate into a thin rectangular parallelepiped, and as shown in FIG. 4, the laminated surface is divided into two equal parts in the vertical direction and two in the horizontal direction. Four polarization parts 33a (first polarization part), polarization part 33b (second polarization part), polarization part 33c (second polarization part), and polarization part 33d (first polarization part) generated by equal division Part) is polarized in the stacking direction and in the same direction.
[0034]
The piezoelectric body 34 is formed by molding a known piezoelectric body such as barium titanate or lead titanate in the same size as the piezoelectric body 33. As shown in FIGS. 5 and 6, almost the entire surface is a single polarization portion 34a. Is polarized in the stacking direction.
The rotor 32 is a known rotor that converts elliptical vibration generated on the end face of the piezoelectric element 31 into a rotational force and transmits it to the outside.
[0035]
As shown in FIG. 4, the electrode 35 covers the entire upper surface of the polarizing portion 33 a and the polarizing portion 33 d located diagonally to each other, and a connection line 35 a provided along the outer peripheral edge of the upper surface of the piezoelectric body 33. A single electrode is formed by connecting the electrodes on each polarization part.
As shown in FIG. 4, the electrode 36 covers the entire upper surface of the polarization portion 33 b and the polarization portion 33 d that are located diagonally to each other, and each connection line 36 a provided at the center of the upper surface of the piezoelectric body 33 is used. One electrode is formed by connecting the electrodes on the polarization part.
[0036]
Here, the connection line 35a is formed thicker than the connection line 36a. The thickness is set so that the impedance of the electrode 35 and the impedance of the electrode 36 are approximately the same.
Therefore, although the total length of the connection line 35a is longer than the total length of the connection line 36a, the difference between the impedance of the electrode 35 and the impedance of the electrode 36 is eliminated.
[0037]
As shown in FIG. 5, the electrode 37 substantially covers the entire upper surface of the piezoelectric body 34 and is grounded.
Further, as described above, the piezoelectric body 33 is integrally laminated on the piezoelectric body 34. Therefore, the electrode 37 grounds not only the electric potential of the upper surface of the polarization portion 34 a of the piezoelectric body 34 but also the electric potentials of the lower surfaces of the polarization portions 33 a to 33 d of the piezoelectric body 33.
[0038]
As shown in FIG. 6, the electrode 38 substantially covers the entire lower surface of the piezoelectric body 34.
Next, the operation of the ultrasonic motor 3 will be described.
First, the case where the rotor 32 is rotated in one direction will be described.
In this case, the same drive signal is input to the electrode 36 and the electrode 38.
Then, the polarization part 33b, the polarization part 33c, and the piezoelectric body 34 of the piezoelectric body 33 expand and contract at the same period.
[0039]
That is, when the end face of the piezoelectric element 31 is in strong contact with the rotor 32 as the piezoelectric body 34 is extended, the polarization portion 33b and the polarization portion 33c are extended, so that the piezoelectric element 31 is indicated by the thick line in FIG. Bend in one direction as shown. Therefore, at this time, the end face of the piezoelectric element 31 rotates the rotor 32 in one direction.
Even if the polarity of the drive signal voltage is reversed and the bending direction of the piezoelectric element 31 is reversed, the piezoelectric element 31 also contracts as the piezoelectric body 34 contracts, so that the end surface of the piezoelectric element 31 contacts the rotor 32. Do not touch. Accordingly, at this time, the operation of the piezoelectric element 31 does not affect the rotation of the rotor 32.
[0040]
Accordingly, the piezoelectric element 31 rotates the rotor 32 in one direction.
Further, when the rotor 32 is rotated in the reverse direction, the same drive signal is input to the electrode 35 and the electrode 38.
Then, the polarization part 33a, the polarization part 33d, and the piezoelectric body 34 of the piezoelectric body 33 expand and contract at the same period.
[0041]
That is, when the end face of the piezoelectric element 31 is in strong contact with the rotor 32 as the piezoelectric body 34 is extended, the polarization portion 33a and the polarization portion 33d are extended, so that the piezoelectric element 31 is indicated by the bold line in FIG. Bend in the opposite direction as shown. Accordingly, at this time, the end face of the piezoelectric element 31 rotates the rotor 32 in the reverse direction.
Even if the polarity of the drive signal voltage is reversed and the bending direction of the piezoelectric element 31 is further reversed, the piezoelectric element 31 also contracts with the contraction of the piezoelectric body 34. Does not touch. Accordingly, at this time, the operation of the piezoelectric element 31 does not affect the rotation of the rotor 32.
[0042]
Accordingly, the piezoelectric element 31 rotates the rotor 32 in the other direction.
Here, since the magnitude of the impedance of the electrode 35 and the magnitude of the impedance of the electrode 36 are the same as described above, when the same drive signal is input, the rotational force of the rotor 32, that is, the drive force of the ultrasonic motor 3. Is constant regardless of the direction of rotation.
[0043]
As described above, in the ultrasonic motor 3 according to the third embodiment of the present invention, since the connection line 35a is thicker than the connection line 36a, the impedance of the electrode 35 is reduced even though the connection line 35a is longer than the connection line 36a. The impedance of the electrode 36 can be matched.
Therefore, according to the ultrasonic motor 3, even if the drive signal is input to the electrode 36 and the rotor 32 is rotated in the reverse direction, the rotational force, that is, the drive force of the ultrasonic motor 3 is input to the electrode 35. Then, it is the same as when the rotor 32 is rotated in the forward direction.
[0044]
<Fourth embodiment>
FIG. 8 is a block diagram of an electronic apparatus 4 with an ultrasonic motor, which is a fourth embodiment of the present invention and in which the above-described ultrasonic motors 1 to 3 are applied to the electronic apparatus.
The electronic device with an ultrasonic motor 4 includes an ultrasonic motor 5, a transmission mechanism 6 that moves in conjunction with a moving body of the ultrasonic motor 5, and an output mechanism 7 that moves based on the operation of the transmission mechanism 6. To achieve.
[0045]
As the ultrasonic motor 5, for example, any of the ultrasonic motors 1 to 3 described above is used. In this case, the moving body described above is the rotor 104 or the rotor 32.
As the transmission mechanism 6, a transmission wheel such as a gear or a friction wheel is used. As the output mechanism 7, for example, a shutter driving mechanism or a lens driving mechanism in a camera, and a pointer driving mechanism or a calendar driving mechanism in an electronic timepiece are used in a storage device, and information is stored in a storage medium in the storage device. A head drive mechanism for driving a head for reading and writing is used. In a machine tool, a cutting tool feed mechanism, a processing member feed mechanism, or the like is used.
[0046]
That is, examples of the electronic device 4 with an ultrasonic motor include an electronic timepiece, a measuring instrument, a camera, a printer, a printing machine, a machine tool, a robot, a moving device, and a storage device.
According to the ultrasonic motor-equipped electronic device 4, the output mechanism 7 is driven by the same amount as when it is driven in the forward direction by the same drive signal even when driven in the reverse direction. That is, since a constant drive amount can be obtained regardless of the drive direction, the electronic apparatus with an ultrasonic motor that can easily control the drive amount is obtained.
[0047]
The present invention is not limited to the above-described embodiments, and can be arbitrarily modified without departing from the spirit of the present invention.
In particular, the present invention can be generally applied to an ultrasonic motor of a type in which the driving direction is reversed by changing the polarization unit that inputs the driving signal, and the same effect can be obtained.
[0048]
In the above-described embodiments, the impedance of each electrode is adjusted by adjusting the width or thickness of the connection line. Naturally, the impedance of each electrode is adjusted by adjusting the thickness and / or width of the entire electrode. You may adjust.
Further, in the ultrasonic motor 3, the width of the connection line 35a is made larger than the width of the connection line 36a so that the impedances of the electrode 35 and the electrode 36 are matched, but the thickness of the connection line 35a is changed to the thickness of the connection line 36a. By making it thicker, the same effect can be obtained.
[0049]
【The invention's effect】
According to the first to fourth aspects of the present invention, the driving force in the reverse direction of the ultrasonic motor matches the driving force when the ultrasonic motor is driven in the forward direction using the same driving signal. An ultrasonic motor capable of controlling force can be manufactured.
Also, according to the invention described in claim 5, since the obtained drive amount that is constant regardless of the driving direction, can be fabricated easily ultrasonic electronic apparatus equipped with the motor control of the driving amount.
[Brief description of the drawings]
FIG. 1A is a schematic top view illustrating a vibrating body 12 and a protrusion 13 that are components of an ultrasonic motor 1 according to a first embodiment of the present invention. FIG. ) Is a schematic top view of the piezoelectric element 11 that is one component of the ultrasonic motor 1, and FIG. 8C is a schematic bottom view of the piezoelectric element 11.
FIG. 2A is a schematic diagram illustrating the configuration of an electrode 16 and an electrode 21 provided on the lower surface of a piezoelectric element 11 in an ultrasonic motor 2 according to a second embodiment of the present invention. FIG. 2B is a schematic cross-sectional view taken along line XX in FIG.
FIG. 3 is a schematic perspective view of an ultrasonic motor 3 according to a third embodiment of the present invention.
4 is a schematic top view of a piezoelectric body 33 that is a constituent element of the ultrasonic motor 3. FIG.
5 is a schematic bottom view of a piezoelectric body 33. FIG.
6 is a schematic bottom view of a piezoelectric body 34 that is a constituent element of the ultrasonic motor 3. FIG.
7A is a diagram for explaining a case where a rotor 32 which is one component of the ultrasonic motor 3 rotates in one direction, and FIG. 7B is a diagram in which the rotor 32 rotates in the opposite direction. It is a figure explaining the case to do.
FIG. 8 is a block diagram of an electronic apparatus 4 with an ultrasonic motor according to a fourth embodiment of the present invention.
FIG. 9 is a schematic cross-sectional view illustrating a configuration of an ultrasonic motor 100 as a conventional example.
10 is a schematic top view illustrating the configuration of the piezoelectric element 101 and the electrodes 105a and 105b, which are one component of the ultrasonic motor 100. FIG.
FIG. 11A is a diagram illustrating a case where a rotor 104 which is one component of the ultrasonic motor 100 rotates in one direction, and FIG. 11B is a diagram in which the rotor 104 rotates in the reverse direction. It is a figure explaining the case to do.
[Explanation of symbols]
1, 2, 3 Ultrasonic motor 4 Electronic device with ultrasonic motor 5 Ultrasonic motor 6 Transmission mechanism 7 Output mechanism 11 Piezoelectric element 11a Polarization section (positive polarization section)
11b Polarization part (reverse polarization part)
12 Vibrating body 13 Protrusion 15 Electrode 16 Electrode (second electrode)
17 electrode (first electrode)
21 electrode (first electrode)
31 Piezoelectric element 32 Rotor 33 Piezoelectric body (first piezoelectric body)
34 Piezoelectric body (second piezoelectric body)
35 electrode (first electrode)
36 electrode (second electrode)
100 Ultrasonic motor 104 Rotor

Claims (5)

A discoid vibrator,
A plurality of protrusions provided on an upper surface of the vibrating body;
A disk-shaped piezoelectric element fixed to the lower surface of the vibrating body;
A rotor that rotates by vibration of the protrusion;
An ultrasonic motor having
The piezoelectric element has electrodes divided in the circumferential direction,
An electrode for short-circuiting every other divided electrode at the inner edge of the piezoelectric element;
Among the divided electrodes, an electrode that is not short-circuited at the inner edge of the piezoelectric element, every other electrode at the outer edge of the piezoelectric element; and
The width of the electrode that short-circuits every other divided electrode at the outer edge of the piezoelectric element is larger than the width of the electrode that short-circuits every other divided electrode at the inner edge of the piezoelectric element. Ultrasonic motor characterized by being thick . A discoid vibrator,
A plurality of protrusions provided on an upper surface of the vibrating body;
A disk-shaped piezoelectric element fixed to the lower surface of the vibrating body;
A rotor that rotates by vibration of the protrusion;
An ultrasonic motor having
The piezoelectric element has electrodes divided in the circumferential direction,
An electrode for short-circuiting every other divided electrode at the inner edge of the piezoelectric element;
Among the divided electrodes, an electrode that is not short-circuited at the inner edge of the piezoelectric element, every other electrode at the outer edge of the piezoelectric element; and
The thickness of the electrode that short-circuits every other divided electrode at the outer edge of the piezoelectric element is less than the thickness of the electrode that short-circuits every other divided electrode at the inner edge of the piezoelectric element. Ultrasonic motor characterized by being thick . A rectangular parallelepiped piezoelectric element;
Four electrodes provided in each of the four regions divided by dividing one surface of the piezoelectric element into two equal parts in the vertical direction and two in the horizontal direction;
An electrode for short-circuiting a pair of electrodes on the diagonal line of the four electrodes at the center of the piezoelectric element;
Of the four electrodes, an electrode that is short-circuited at the outer peripheral edge of the piezoelectric element, two electrodes that are not short-circuited at the center of the piezoelectric element;
An ultrasonic motor characterized in that a width of an electrode that is short-circuited at an outer peripheral edge portion of the piezoelectric element is larger than a width of an electrode that is short-circuited at a central portion of the piezoelectric element . A rectangular parallelepiped piezoelectric element;
Four electrodes provided in each of the four regions divided by dividing one surface of the piezoelectric element into two equal parts in the vertical direction and two in the horizontal direction;
An electrode for short-circuiting a pair of electrodes on the diagonal line of the four electrodes at the center of the piezoelectric element;
Of the four electrodes, an electrode that is short-circuited at the outer peripheral edge of the piezoelectric element, two electrodes that are not short-circuited at the center of the piezoelectric element;
The ultrasonic motor is characterized in that the thickness of the electrode that is short-circuited at the outer peripheral edge of the piezoelectric element is thicker than the thickness of the electrode that is short-circuited at the center of the piezoelectric element . The ultrasonic motor according to any one of claims 1 to 4 is provided.
An electronic device with an ultrasonic motor.

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