JP5776269B2 - Piezoelectric actuator, robot and robot hand - Google Patents

Description

  The present invention relates to a piezoelectric actuator, a robot, and a robot hand.

  The piezoelectric actuator is a driving device having at least a piezoelectric element that converts a driving voltage such as a high-frequency AC voltage into mechanical vibration and a driven portion that is driven by the piezoelectric element. A piezoelectric motor is a type of piezoelectric actuator. The piezoelectric motor is a driving device that uses a rotor as the above-mentioned driven portion, and is a driving device that can use the vibration of the piezoelectric element as a rotational force. Generally, a piezoelectric element is used by being laminated with a diaphragm that reinforces the piezoelectric element and vibrates together with the piezoelectric element. In general, the piezoelectric element is held or fixed so as to be vibrated by another member. For example, Patent Document 1 proposes a method of fixing a piezoelectric element to a support base by a support portion added to the piezoelectric element.

JP 2008-122381 A

  However, the above-described piezoelectric actuator has a problem that the support portion may hinder the operation of the piezoelectric element and the diaphragm, that is, vibration. The support portion is a member that fixes the vibration plate and also vibrates with the vibration plate. Therefore, depending on the shape or material, there is a problem that the vibration of the diaphragm is hindered and the performance of the piezoelectric actuator is reduced.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] A piezoelectric actuator of this application example includes a laminated body in which rectangular diaphragms are stacked in a plan view having a piezoelectric element and short sides and long sides, and a long side from the long side of the diaphragm to the long side. A piezoelectric actuator including a support portion extending in a direction orthogonal to each other, wherein the support portion has a width in a direction along the long side and a size in a direction protruding from the long side of the support portion. The ratio with a certain length is in the range of about 1: 1 to about 1: 4.

  With such a configuration, the vibration of the piezoelectric element can be efficiently converted into a driving force. Therefore, it is possible to obtain a piezoelectric actuator that is reduced in size and weight and has reduced power consumption.

  Application Example 2 A piezoelectric actuator according to the above-described piezoelectric actuator, wherein the ratio is approximately 1: 1.

  With such a configuration, the vibration of the piezoelectric element can be converted into driving force more efficiently. Therefore, it is possible to obtain a piezoelectric actuator that is further reduced in size and weight and further reduced in power consumption.

  Application Example 3 The piezoelectric actuator described above, wherein the ratio is in a range of about 1: 3 to about 1: 4.

  With such a configuration, the vibration of the piezoelectric element can be converted into driving force more efficiently. Therefore, it is possible to obtain a piezoelectric actuator that is further reduced in size and weight and further reduced in power consumption.

  Application Example 4 In the piezoelectric actuator described above, the diaphragm has a long side dimension of approximately 7.0 mm and a short side dimension of approximately 2.0 mm.

  A piezoelectric actuator provided with a diaphragm having such dimensions can convert the vibration of the piezoelectric element into driving force more efficiently. Therefore, it is possible to obtain a piezoelectric actuator that is further reduced in size and weight and further reduced in power consumption.

  Application Example 5 In the piezoelectric actuator described above, the diaphragm has a long side dimension of approximately 21.0 mm and a short side dimension of approximately 5.6 mm.

  A piezoelectric actuator provided with a diaphragm having such dimensions can convert the vibration of the piezoelectric element into driving force more efficiently. Therefore, it is possible to obtain a piezoelectric actuator that is further reduced in size and weight and further reduced in power consumption.

  Application Example 6 In the piezoelectric actuator described above, the diaphragm and the support portion are made of SUS301 or Fe-42Ni alloy.

  A piezoelectric actuator including a diaphragm formed of such a material can convert the vibration of the piezoelectric element into a driving force more efficiently. Therefore, it is possible to obtain a piezoelectric actuator that is further reduced in size and weight and further reduced in power consumption.

  Application Example 7 A robot hand including the piezoelectric actuator described above.

  With such a configuration, the robot hand can be made smaller and lighter than other robot hands that use the same work.

  Application Example 8 A robot including the above-described robot hand.

  With such a configuration, the robot can be reduced in size and weight as compared with other robots that use the same work. And if it is a robot of such a structure, the same operation | work can be implemented with low power consumption compared with another robot.

1 is an exploded perspective view of a piezoelectric motor according to a first embodiment. The top view which shows the division of the 2nd electrode of a piezoelectric element with a protrusion part. The top view which shows the vibrating body with which the piezoelectric motor of 1st Embodiment is provided. The figure which shows the result of having calculated | required the relationship between a longitudinal resonance frequency and a support part length in both the time of fixation and non-fixation. The figure which shows the result of having calculated | required the relationship between a bending resonant frequency and support part length in both the time of fixation and non-fixation. The figure which shows the result of having calculated | required the difference of the longitudinal resonance frequency at the time of fixation, and the longitudinal resonance frequency at the time of non-fixation. The figure which shows the result of having calculated | required the difference of the bending resonance frequency at the time of fixation, and the bending resonance frequency at the time of non-fixing. The figure which shows the result of having calculated | required the vibration at the time of applying the drive voltage of a bending resonance frequency to the vibrating body of 1st Embodiment. The figure which shows the result of having calculated | required the vibration at the time of applying the drive voltage of a bending resonance frequency to the vibrating body concerning 2nd Embodiment. FIG. 3 is a diagram illustrating a vibrating body according to the first embodiment. The figure which shows the longitudinal resonance frequency in case the thickness of the diaphragm of Example 1 is about 0.5 mm about both the time of fixation and non-fixation. The figure which shows the longitudinal resonance frequency in case the thickness of the diaphragm of Example 1 is about 1.0 mm about both the time of fixation and non-fixation. The figure which shows the bending resonance frequency in case the thickness of the diaphragm of Example 1 is about 0.5 mm about both the time of fixation and non-fixation. The figure which shows the bending resonance frequency in case the thickness of the diaphragm of Example 1 is about 1.0 mm about both the time of fixation and non-fixation. The figure which shows the difference of the resonance frequency at the time of fixation and the resonance frequency at the time of non-fixation in the case where the thickness of the diaphragm of Example 1 is about 0.5 mm about both a longitudinal resonance frequency and a bending resonance frequency. The figure which shows the difference of the resonance frequency at the time of fixation and the resonance frequency at the time of non-fixation in the case where the thickness of the diaphragm of Example 1 is about 1.0 mm about both a longitudinal resonance frequency and a bending resonance frequency. The figure which shows the result of having calculated | required the longitudinal resonant frequency and bending | flexion resonant frequency at the time of fixing this vibrating body in the multiple types of vibrating body from which material differs. The figure which shows the result of having calculated | required the longitudinal resonant frequency and bending | flexion resonant frequency when not fixing this vibrating body in the multiple types of vibrating body from which material differs. For multiple types of vibrators with different materials, the difference between the longitudinal resonant frequency when fixed and the longitudinal resonant frequency when not fixed, and the difference between the flexural resonant frequency when fixed and the flexural resonant frequency when not fixed were determined. The figure which shows a result. The figure which shows the outline of the robot concerning 3rd Embodiment. The figure which shows the outline of the robot hand concerning 3rd Embodiment. The figure which shows the outline of the 1st finger | toe with which a robot hand is provided. The top view which shows the vibrating body concerning 2nd Embodiment.

  Hereinafter, a piezoelectric actuator according to an embodiment of the present invention will be described with reference to the drawings. The embodiment of the present invention is not limited to the structure and shape shown in the following drawings. In each of the following drawings, the scale of each component is different from the actual scale so that each component can be recognized in the drawing.

(First embodiment)
The piezoelectric motor as a piezoelectric actuator of this embodiment and each embodiment described later is characterized by the shape of the support portion 31 that is a part of the vibrating body 11. Therefore, first, the outline of the piezoelectric motor 1 will be described, and then the support portion 31 will be described.

<Piezoelectric motor>
FIG. 1 is an exploded perspective view of the piezoelectric motor 1 according to the first embodiment of the present invention. As shown in the figure, a piezoelectric motor 1 includes a base 2, a rotor (rotating body) 3 as a driven part, a vibrating body 11 including a laminate of a piezoelectric element 30 and a diaphragm 21, and an urging force for fixing the vibrating body 11. Means 80 and the like. The rotor 3 has a rotation axis r substantially perpendicular to the one surface of the base 2.

  As shown in the figure, the vibrating body 11 includes a vibration plate 21 and piezoelectric elements 30 disposed on both surfaces of the vibration plate. As will be described later, the piezoelectric element 30 is a member including a piezoelectric layer 40 that vibrates by application of an alternating voltage as a driving voltage, and is rectangular in plan view. The diaphragm 21 is a plate-like member made of SUS301 having a thickness of about 0.5 mm, and has the same planar shape as the piezoelectric element 30. The diaphragm 21 also functions to reinforce the piezoelectric element 30. Although the vibration plate 21 itself does not vibrate, since it is laminated with the piezoelectric element 30, the vibration plate 21 vibrates substantially equally when the piezoelectric element 30 vibrates.

  The vibrating body 11 further includes a support portion 31 and a protruding portion (sliding portion) 25. The support portion 31 is a member protruding from both long sides of the diaphragm 21. The support portion 31 has an arm-shaped portion extending in a direction substantially orthogonal to the long side and a portion that extends in a substantially circular shape located at the tip of the arm-shaped portion. And the through-hole 27 is formed in the above-mentioned substantially circular part. The diaphragm 21 and the support part 31 are integrally molded from the above-described SUS301 plate material. On the other hand, the protruding portion 25 is made of alumina, and is bonded to one end portion in the long side direction of the diaphragm 21 so as to protrude from the end portion. Note that the protruding portion 25 can be formed integrally with the diaphragm in the same manner as the support portion 31.

  The vibrating body 11 is fixed to a biasing means 80 (described later) via the support portion 31 (more precisely, the through hole 27) so that the protruding portion 25 contacts the rotor 3 with a predetermined pressure. When the piezoelectric element 30 vibrates due to the application of the drive voltage, the diaphragm 21 that is a member laminated on the piezoelectric element 30 and the entire vibrator 11 including the diaphragm vibrate. As will be described later, the protruding portion 25 protruding from the end of the diaphragm 21 vibrates so as to draw an elliptical orbit. The rotor 3 fulfills the function as the piezoelectric motor 1 by being transmitted at a predetermined speed by the vibration drawing the elliptical orbit.

  Here, the piezoelectric element 30 will be described. As shown in the figure, the piezoelectric element 30 is provided on the opposite side of the piezoelectric layer 40, the first electrode 50 provided on the diaphragm 21 side of the piezoelectric layer 40, and the first electrode 50 of the piezoelectric layer 40. Second electrode 60 formed. The first electrode 50 is formed over substantially the entire surface of the piezoelectric layer 40 on the vibration plate 21 side. On the other hand, the second electrode 60 is divided into five electrodes (second electrodes 60 a to 60 e) that are electrically isolated from each other by the first groove portion 71 and the second groove portion 72. The first electrode 50 functions as a common electrode for the plurality of divided second electrodes 60 (60a to 60e). The second electrode 60 (60a to 60e) and the groove portions (71, 72) will be described later.

The piezoelectric layer 40 is made of a piezoelectric material having an electromechanical conversion action, particularly a metal oxide having a perovskite structure represented by the general formula ABO ₃ among piezoelectric materials. As the piezoelectric layer 40, for example, a ferroelectric material such as lead zirconate titanate (PZT) or a material obtained by adding a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide to the ferroelectric material is suitable. Specifically, lead titanate (PbTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La), TiO ₃ ) ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ) or lead magnesium titanate zirconate titanate (Pb (Zr, Ti) (Mg, Nb) O ₃ ), etc. Can do.

  FIG. 2 is a plan view showing a section of the second electrode 60 of the piezoelectric element 30 together with the protruding portion 25. The second electrode 60 is divided into approximately third grades in the short side direction by the first groove 71. Then, the two electrodes on both sides in the short side direction are further divided into approximately two equal parts in the long side direction by the second groove portion 72. Therefore, the second electrode 60 is divided into a total of five electrodes, the second electrodes 60a to 60e.

  When a drive voltage is selectively applied only to the second electrode 60a, the second electrode 60e, and the second electrode 60c, the piezoelectric element 30 is mainly centered in the long side direction of the piezoelectric element 30 by the second electrode 60c. A longitudinal primary vibration that expands and contracts in the center is excited. In addition, the second electrode 60a and the second electrode 60e mainly excite a bending secondary vibration that bends in the direction orthogonal to the longitudinal primary vibration in the plane of the piezoelectric element 30, that is, along the minor axis direction of the piezoelectric element 30. The

The degree of both vibrations, that is, the amplitude of the piezoelectric element 30 varies depending on the frequency of the drive voltage. When the reciprocal of the amplitude is the impedance of the vibrating body 11, the frequency at which the impedance is minimum with respect to the driving frequency, that is, the frequency at which the amplitude reaches a peak appears for each of both vibrations. Such a frequency is a resonance frequency (resonance point). The frequency at which the longitudinal primary vibration peaks is the longitudinal resonance frequency (fr1), and the frequency at which the bending secondary vibration peaks is the bending resonance frequency (fr2). The longitudinal resonance frequency is a lower value (frequency) than the bending resonance frequency. By driving the piezoelectric actuator at a frequency approximately in the middle between both resonance frequencies, the piezoelectric element 30 can be excited with both longitudinal primary vibration and bending secondary vibration.
Then, by combining the longitudinal primary vibration and the bending secondary vibration, the piezoelectric element 30 can be excited to bend and vibrate while expanding and contracting as indicated by a two-dot chain line in FIG. As a result, the projecting portion 25 vibrates while drawing an elliptical orbit R combining the two vibrations.

  When the protrusion 25 is rotated in the opposite direction, the second electrode 60 to which the drive voltage is applied in the piezoelectric element 30 may be switched symmetrically about the center line along the long side direction of the vibrator 11. That is, a longitudinal primary vibration obtained by selectively applying a driving voltage only to the second electrode 60b, the second electrode 60d, and the second electrode 60c among the plurality of divided second electrodes 60, and the second electrode By combining the bending secondary vibration obtained by 60b and the second electrode 60d, it is possible to obtain an elliptical vibration that rotates in a direction opposite to the illustrated rotation (vibration) direction (clockwise direction).

  Here, returning to FIG. 1, the biasing means 80 will be described. The biasing means 80 is in contact with the holding member 81 that holds the vibrating body 11, a spring member 82 such as a coil spring having one end fixed to the holding member 81, and the other end of the spring member 82 and is fixed to the base 2. And at least a support pin 83.

  The holding member 81 includes a pair of fixed portions 84 to which the support portion 31 of the vibrating body 11 is fixed, and a slide portion that is integrally provided between the fixed portions 84 and is slidably supported with respect to the base 2. 85. In the fixing portion 84, a female screw portion 87 to which the screw member 86 is screwed is formed corresponding to the through hole 27 of the support portion 31. The vibrating body 11 is fixed to the holding member 81 by screwing a screw member 86 inserted through a through hole 27 described later of the support portion 31 into the female screw portion 87.

  The slide portion 85 is provided with two slide holes 88 that are long holes penetrating in the thickness direction and extending in the slide direction. The slide portion 85 is supported so as to be slidable with respect to the base 2 by slide pins 89 inserted into the slide holes 88 and fixed to the base 2.

  The spring member 82 is a coil spring disposed along the slide direction of the slide portion 85. The spring member 82 is arranged such that one end is fixed to the fixing portion 84 and the other end is in contact with the side surface of the support pin 83 fixed to the base 2. The spring member 82 urges, that is, presses, the protrusion 25 included in the vibrating body 11 toward the rotor 3. In this state, the rotor 3 can be rotationally driven by generating a vibration that draws an elliptical orbit in the piezoelectric element 30. As described above, the piezoelectric element 30 can generate elliptical vibrations in an arbitrary direction. Therefore, the piezoelectric motor 1 of the present embodiment can rotate in either the clockwise direction (forward rotation) or the counterclockwise direction (reverse rotation).

  As described above, the piezoelectric element 30 vibrates when a driving voltage is applied. The vibrating plate 21 laminated with the piezoelectric element 30 and the vibrating body 11 including the laminated body of the piezoelectric element 30 and the vibrating plate 21 vibrate in the same manner. That is, the piezoelectric element 30 and the piezoelectric motor 1 having the piezoelectric element as a constituent element convert electric energy into kinetic energy.

The vibrating body 11 is fixed to the fixing portion 84 of the holding member 81 via the support portion 31. The laminated body of the piezoelectric element 30 and the diaphragm 21 vibrates while being fixed to the holding member 81 by the support portion 31. The support portion 31 has a function of preventing the above-described vibration as much as possible and fixing the vibrating body 11 to the holding member 81 (the fixing portion 84 thereof). Therefore, the aspect of the support portion 31 greatly affects the energy conversion efficiency, which is the efficiency of converting electrical energy into kinetic energy.
The piezoelectric motor 1 of the present embodiment improves the above-described energy conversion efficiency by devising the shape (planar shape) of the support portion 31. Hereinafter, the support part 31 with which the piezoelectric motor 1 of this embodiment is provided is demonstrated.

<Supporting part>
FIG. 3 is a plan view showing the vibrating body 11 provided in the piezoelectric motor 1 of the present embodiment. In addition, illustration of the piezoelectric element 30 is abbreviate | omitted in this figure. The diaphragm 21 and the support portion 31 are integrally formed by molding SUS301 having a thickness of about 0.5 mm as a preferred example. The diaphragm 21 has a long side a of about 7.0 mm and a short side b of about 2.0 mm.

The support portion 31 is formed so as to protrude from the approximate center in the long side direction of the diaphragm 21. And the support part 31 has an arm-shaped part and the circular part of the edge part as mentioned above. A through hole 27 is formed in the circular portion.
Here, the width that is the dimension in the direction along the long side of the diaphragm 21 in the arm-shaped portion of the support portion 31 is defined as the support portion width B. The length of the arm-shaped portion of the support portion 31 that is a dimension in a direction protruding from the long side of the diaphragm 21, that is, the dimension in the direction in which the support portion 31 extends is defined as a support portion length L.

  The support part 31 of this embodiment in a preferred example has a support part width B of approximately 0.6 mm and a support part length L of approximately 2.0 mm. Therefore, the ratio of the support part width B to the support part length L is approximately 1: 3.3. The support part 31 of this embodiment sets the ratio of the support part width B and the support part length L to such a value, so that the vibrating body 11 can be applied to the biasing means 80 without greatly disturbing the vibration of the vibrating body. It is possible to fix. That is, the piezoelectric motor 1 of the present embodiment obtains high energy conversion efficiency by making the support portion 31 have the shape described above. In the following description, the influence of the ratio of the support portion width B and the support portion length L on the vibration of the vibrating body 11 will be described.

4 to 7 are forms similar to the vibrating body 11 and the vibrating body 11 of the present embodiment, in which the support part width B is 0.6 mm, and only a plurality of support part length L dimensions are changed. It is a figure which shows the result of having simulated the resonant frequency etc. of the vibrating body into the case where this vibrating body is fixed, and the case where it is not fixed.
In order to vibrate the vibrating body 11, it is necessary to fix the vibrating body 11 via the support portion 31. However, in order to make the shape of the support portion 31 suitable, it is necessary to confirm the influence of the shape of the support portion 31 on the vibration. Therefore, in FIGS. 4 to 7, when the vibrating body 11 is fixed and when the vibrating body 11 is not fixed, in other words, when the vibrating body 11 is fixed and vibrated via the ideal support portion 31 that does not affect the vibration. Both are sought by simulation.

  4 shows the relationship between the longitudinal resonance frequency fr1 and the support portion length L when the support portion 31 of the vibrating body 11 is fixed to the fixing portion 84, that is, when the vibrating body 11 is fixed and when the vibrating body 11 is not fixed. That is, it is a figure which shows the result calculated | required in both the state which floated in the air, ie, the vibrating body 11 is not fixed. As shown in the figure, the support portion length L is in the range of 0.4 mm to 2.4 mm, that is, the ratio of the support portion width B to the support portion length L is approximately 1: 0.66 to approximately 1: 4.0. The longitudinal resonance frequency fr1 when fixed and the longitudinal resonance frequency fr1 when not fixed are not significantly different from each other. That is, when the support portion 31 in such a range is used, it is estimated that even when the vibrating body 11 is fixed to the fixing portion 84, longitudinal primary vibration substantially equivalent to that when not fixed is obtained.

  FIG. 5 is a diagram illustrating a result of obtaining the relationship between the bending resonance frequency fr2 and the support portion length L in both the fixed state and the non-fixed state. As shown in the figure, the support portion length L is in the range of 1.5 mm to 3.0 mm, that is, the ratio of the support portion width B to the support portion length L is in the range of approximately 1: 2.5 to approximately 1: 5.0. The flexural resonance frequency fr2 when fixed and the flexural resonance frequency fr2 when not fixed are not significantly different.

  However, in the vicinity of the support portion length L of approximately 1.1 mm, that is, in the vicinity of the above-described ratio of B to L of approximately 1: 1.8, both the bending resonance frequencies fr2 are extremely different. Further, even when the support portion length L is in the range of 0.1 mm to 0.6 mm, that is, the ratio of B to L is approximately 1: 0.17 to approximately 1: 1.7, both the bending resonance frequencies fr2 are satisfied. Is approximately 13 kHz, that is, approximately 4.5% apart.

FIG. 6 is a diagram illustrating a result of obtaining a difference between the longitudinal resonance frequency fr1 when fixed and the longitudinal resonance frequency fr1 when not fixed. As shown in the figure, when the support portion length L is in the range of 0.4 mm to 2.4 mm, that is, the ratio of B and L is in the range of about 1: 0.66 to about 1: 4, the difference between the two longitudinal resonance frequencies fr1. Is within about 1 kHz.
FIG. 7 is a diagram illustrating a result of obtaining a difference between the flexural resonance frequency fr2 when fixed and the flexural resonance frequency fr2 when not fixed. In the range where the support portion length L is 1.8 mm to 3.0 mm, that is, the ratio of B to L is approximately 1: 3 to approximately 1: 5, the above-described difference is within approximately 2 kHz.

As described above, with respect to the vibrating body 11 including the support portion 31 having the support portion width B of approximately 0.6 mm, the longitudinal resonance frequency fr1 in both the fixed state and the non-fixed state is obtained by simulation. In the range of 0.4 mm to 2.4 mm, it can be seen that there is little difference between the longitudinal resonance frequencies fr1.
Similarly, as a result of obtaining the bending resonance frequency fr2 in both the fixed state and the non-fixed state for the above-mentioned vibrating body 11 by simulation, both bending resonances were obtained when the support portion length L was in the range of 1.8 mm to 3.0 mm. It can be seen that the difference in the frequency fr2 is small.
Therefore, when the support portion length L is 1.8 mm to 2.4 mm, that is, when the ratio of B and L is in the range of about 1: 3.3 to about 1: 4, the vibrating body 11 is fixed and unfixed. It turns out that the difference between the resonance frequencies is small in both the longitudinal resonance frequency fr1 and the bending resonance frequency fr2.

  The fact that the difference between the resonance frequency at the time of fixation and the resonance frequency at the time of non-fixation is small means that the influence of fixing the vibration body 11 on the vibration of the vibration body 11 is small. That is, when the vibrating body 11 is fixed to the holding member 81 (the fixing portion 84 thereof) with the support portion 31 having the support portion length L in the above range, it is estimated that the energy conversion efficiency is less decreased.

  As described above, the above-described ratio in the support portion 31 included in the vibrating body 11 of the present embodiment is approximately 1: 3.3, which is within the above-described range of approximately 1: 3 to approximately 1: 4. Therefore, in the piezoelectric motor 1 of the present embodiment, the electric energy applied to the piezoelectric element 30 is converted to the rotor 3 with high conversion efficiency even though the vibrating body 11 is fixed to the holding member 81 via the support portion 31. Can be converted into a rotational motion.

  FIG. 8 is a diagram illustrating a result of obtaining vibration (deformation) by simulation when the driving voltage having the bending resonance frequency fr2 is applied to the vibrating body 11 in the piezoelectric motor 1 of the present embodiment. FIG. 8A is a diagram illustrating vibration when the vibrating body 11 is fixed, and FIG. 8B is a diagram illustrating vibration when the vibrating body 11 is not fixed. The vibration body 11 being fixed means that the support portion 31 of the vibration body 11 is fixed to the holding member 81 by the screw member 86 as described above. That is, that the vibrating body 11 is fixed means that the support portion 31 is fixed.

  As shown in FIG. 8, the vibrating body 11 included in the piezoelectric motor 1 of the present embodiment, that is, the vibrating body including the support portion 31 in which the ratio of the support portion width B to the support portion length L is approximately 1: 3.3 is as follows. The difference between the vibration when fixed and the vibration when not fixed is very small. This is considered to be because when the ratio of B to L of the support portion 31 is approximately 1: 3.3, the support portion 31 and the portion of the diaphragm 21 that are connected to the support portion serve as vibration nodes.

  When a long member bends and vibrates, generally, “belly” and “node” appear. The “antinode” is a portion where the amplitude is maximum, and the “node” is a portion where the amplitude located between the antinode and the antinode is minimum. The knot portion does not vibrate even when not fixed. Therefore, when the portion connected to the support portion 31 of the diaphragm 21 becomes a vibration node, there is little difference between the vibration at the time of fixation and the vibration at the time of non-fixation. The fact that the difference between the vibration at the time of fixation and the vibration at the time of non-fixation is small means that even when the vibrating body 11 is fixed, a similar vibration at the time of non-fixation, that is, a substantially ideal vibration is obtained. It is that.

<Effect of this embodiment>
As described above, the piezoelectric motor 1 according to the present embodiment, that is, the piezoelectric motor 1 including the support portion 31 described above, can obtain substantially ideal vibration even though the vibrating body 11 is fixed. Yes. Therefore, the electric energy applied to the piezoelectric element 30 can be efficiently converted into the rotation of the rotor 3. That is, it has high energy conversion efficiency, and energy saving can be realized.

(Second Embodiment)
Next, a piezoelectric motor according to a second embodiment will be described. The piezoelectric motor of this embodiment has substantially the same configuration as the piezoelectric motor 1 of the first embodiment, and only the ratio of the support portion width B and the support portion length L of the support portion 31 is different. Therefore, in the present embodiment, illustration and description of the piezoelectric motor are omitted, and only the vibrating body and the like will be described. In the following description, “the vibrating body 12 included in the piezoelectric motor of the present (second) embodiment” is referred to as “the vibrating body 12 of the present (second) embodiment”. The same applies to other components.

  FIG. 23 is a diagram illustrating the vibrating body 12 according to the present embodiment. The vibrating body 12 includes a diaphragm 22, a support portion 32, a protruding portion 25, and a through hole 27. Note that illustration of the piezoelectric element 30 is omitted as in FIG. The diaphragm 22 of this embodiment is substantially the same as the diaphragm 21 of the first embodiment described above. That is, it is formed of a SUS301 material having a thickness of approximately 0.5 mm, and is a rectangle having a long side a of approximately 7.0 mm and a short side b of approximately 2.0 mm. And the support part 32 of this embodiment differs only in the support part 31 and the support part length L of 1st Embodiment. That is, the support part 32 of this embodiment has a support part width B of approximately 0.6 mm and a support part length L of approximately 0.6 mm. Therefore, the ratio of the support part width B to the support part length L is approximately 1: 1.

As described above and as shown in FIGS. 4 and 6, the longitudinal resonance frequency fr1 at the time of fixation and the longitudinal resonance frequency fr1 at the time of non-fixation have a ratio of the support portion width B to the support portion length L of about 1: 0. In the range of .66 to approximately 1: 4.0, there is no significant deviation. That is, even when the ratio is approximately 1: 1, the longitudinal resonance frequency fr1 has a small difference between when it is fixed and when it is not fixed.
5 and 7, when the support portion length L is approximately 0.6 mm, the difference between the flexural resonance frequency fr2 when fixed and the flexural resonance frequency fr2 when not fixed is approximately 13 kHz, and the ratio is approximately 4 .5%, which is not significantly different. And the sudden change (bending resonance frequency) like the case where the support part length L is 1.1 mm vicinity is not seen.

  As described above, when the support portion 32 of the present embodiment is used, both the longitudinal resonance frequency fr1 and the bending resonance frequency fr2 are the same as in the case of using the support portion 31 of the first embodiment. It does not fluctuate so much between when fixed and when not fixed. Therefore, even if the vibrating body 12 of the present embodiment is fixed to the fixing portion 84 (see FIG. 1) of the holding member 81 by the support portion 32, it is estimated that the decrease in energy conversion efficiency is small.

  FIG. 9 is a diagram corresponding to FIG. 8 in the first embodiment. That is, FIG. 9 is a diagram illustrating a result of a vibration obtained by applying a drive voltage having a bending resonance frequency fr2 to the vibrating body 12 by simulation. FIG. 9A is a diagram illustrating vibration when the vibrating body 12 is fixed. FIG. 9B is a diagram illustrating vibration when the vibrating body 12 is not fixed.

  As shown in the figure, the vibrating body 12 according to the present embodiment, that is, the vibrating body 12 including the support portion 32 having a ratio of the support portion width B to the support portion length L of approximately 1: 1, is fixed and vibrated. There is little difference with vibration when not done. This is considered to be because the portion of the support portion 32 and the diaphragm 22 connected to the support portion becomes a vibration node, similarly to the vibrating body 11 of the first embodiment. Therefore, even if the vibrating body 12 including the support portion 32 of the present embodiment is fixed, it can obtain vibration similar to the vibration at the time of non-fixing, that is, substantially ideal vibration.

<Effect of this embodiment>
As described above, the piezoelectric motor including the support portion 32 according to the present embodiment can obtain substantially ideal vibration even though the vibrating body 12 is fixed. Therefore, the electric energy applied to the piezoelectric element 30 can be efficiently converted into the rotation of the rotor 3, and energy saving can be realized.

  Further, the vibrating body 12 of the present embodiment has a shorter support portion length L than the vibrating body 11 of the first embodiment. Therefore, when the vibrating body 12 of the present embodiment is used, there is an advantage that the piezoelectric motor can be reduced in size. The diaphragm 22 of the present embodiment is the same size as the diaphragm 21 of the first embodiment. Therefore, the size of the piezoelectric element 30 laminated on the diaphragm is not changed. Therefore, the driving force exhibited by the vibrating body 12 of the present embodiment is almost the same as the driving force exhibited by the vibrating body 11 of the first embodiment. In other words, the piezoelectric motor including the vibrating body 12 according to the embodiment can relatively reduce the outer dimension with respect to the driving force. Therefore, by using the vibrating body 12 of the present embodiment, a piezoelectric motor that is energy-saving and miniaturized can be realized.

  Next, a case where the dimensions of the vibrating body and the thickness of the diaphragm included in the vibrating body vary will be described as an example.

Example 1
First, as Example 1, the resonance frequency and the like in the case where the dimensions of the vibrating body and each element constituting the vibrating body are enlarged as compared with the dimensions in each of the above embodiments are shown. FIG. 10 is a diagram illustrating the vibrating body 13 according to the first embodiment. The vibrating body 13 includes a diaphragm 23, support portions 33 (33 a and 33 b), and a protruding portion 25. Note that illustration of the piezoelectric element 30 is omitted as in FIGS. 3 and 23 described above.

FIG. 10A is a diagram illustrating the vibrating body 13 including the diaphragm 23 and a support portion 33a formed integrally with the diaphragm. FIG. 10B is a diagram illustrating the vibrating body 13 including the diaphragm 23 and a support portion 33b formed integrally with the diaphragm. The diaphragm 23 is a rectangular plate-like member having a long side a having a dimension of approximately 21 mm and a short side b having a dimension of approximately 5.6 mm in plan view. Therefore, the ratio of the long side a and the short side b (size) is similar to the ratio in the diaphragms (21, 22) of the first and second embodiments described above.
The material of the diaphragm 23 is SUS301, and the thickness is approximately 0.5 mm or approximately 1.0 mm. Accordingly, there are two types of thicknesses of the support portion 33 (a, b) formed integrally with the vibration plate 23, approximately 0.5 mm or approximately 1.0 mm.

  The support portion 33a and the support portion 33b are different in the ratio of the support portion width B and the support portion length L. The support part 33a has a support part width B of approximately 2.0 mm and a support part length L of approximately 2.0 mm. Therefore, the ratio of the support part width B to the support part length L is approximately 1: 1. The support part 33b has a support part width B of approximately 2.0 mm and a support part length L of approximately 7.0 mm. Therefore, the ratio of the support portion width B to the support portion length L is approximately 1: 3.5, and is included in the range of approximately 1: 3 to approximately 1: 4.

  11 to 16, various types of support portions having a support portion width B of approximately 2.0 mm and a support portion length L of approximately 0.4 to approximately 8.0 mm are combined with the diaphragm 23 of the first embodiment. It is a figure which shows the resonant frequency etc. in the case about both the time of fixation of the vibrating body 13, and the time of non-fixation. That is, it is a diagram showing the resonance frequency and the like when various support parts including the support part 33 (a, b) of the present embodiment are combined with the diaphragm 23.

  FIG. 11 is a diagram illustrating the longitudinal resonance frequency in the case where the thickness of the diaphragm 23 is approximately 0.5 mm, both when fixed and when not fixed. FIG. 12 is a diagram illustrating the longitudinal resonance frequency in the case where the thickness of the diaphragm 23 is approximately 1.0 mm, both when fixed and when not fixed. FIG. 13 is a diagram illustrating the bending resonance frequency when the thickness of the diaphragm 23 is approximately 0.5 mm, both when the diaphragm 23 is fixed and when it is not fixed. FIG. 14 is a diagram illustrating the flexural resonance frequency when the thickness of the diaphragm 23 is approximately 1.0 mm, both when fixed and when not fixed. FIG. 15 is a diagram illustrating the difference between the resonance frequency when the diaphragm 23 is fixed and the resonance frequency when the diaphragm 23 is not fixed, for both the longitudinal resonance frequency and the bending resonance frequency. FIG. 16 is a diagram illustrating the difference between the resonance frequency when the diaphragm 23 is fixed and the resonance frequency when the diaphragm 23 is not fixed, for both the longitudinal resonance frequency and the bending resonance frequency.

  As described above, the diaphragm 23 and the support portion 33 (a, b) of Example 1 have dimensions approximately three times that of the diaphragm 21 and the support portion 31 of the first embodiment in plan view. . In such a case, as shown in FIGS. 11 to 16, the resonance frequency and the like tend to be similar to the resonance frequency and the like in the first embodiment. In particular, the bending resonance frequency is remarkably similar. That is, when the ratio of the support part width B to the support part length L is approximately 1: 1, or when the ratio is within the range of approximately 1: 3 to approximately 1: 4, the resonance frequency of the fixed state and the non-fixed state The difference is declining. Therefore, as long as the ratio of the support part width B to the support part length L is the above-described value (or range), even if the dimensions (sizes) of the diaphragm and the support body fluctuate, the drive voltage is set to the rotor 3. It is possible to improve the conversion efficiency for converting to the rotation of.

  11, 13, and 15, and FIGS. 12, 14, and 16, the thicknesses of the diaphragm 23 and the support portions (33 a and 33 b) are as follows. The difference between the resonance frequency when fixed and the resonance frequency when not fixed is not so much affected. That is, when the ratio of the support portion width B to the support portion length L is approximately 1: 1, or when the ratio is within a range of approximately 1: 3 to approximately 1: 4, regardless of the thickness of the diaphragm 23 and the like. The effect of improving the energy conversion efficiency described above can be obtained. Accordingly, it is easy to increase the thickness of the diaphragm and the like in accordance with the increase in required driving force.

  As described above, by using the result of Example 1 shown in FIG. 6 and the results of the first and second embodiments, it becomes easy to set the shape and the like of the support portion, and support the piezoelectric motor. The manufacturing conditions of the part can be simplified. That is, it becomes possible to realize a piezoelectric motor with high energy conversion efficiency, that is, an energy-saving piezoelectric motor, regardless of the required driving force or the like.

(Example 2)
Next, as Example 2, a case where the materials of the diaphragm and the support portion are changed will be described. The diaphragm and the support part of the second embodiment are similar to the diaphragm 23 and the support part 33 of the first embodiment. That is, the long side a is about 21 mm, the short side b is about 5.6 mm, and the support width B is about 2.0 mm. The thickness of the diaphragm and the support part is one kind of about 0.5 mm. The difference from the first embodiment is the material for forming the diaphragm and the support portion. The diaphragm and the support part of Example 2 are made of three kinds of materials: anisotropic SUS301, anisotropic 42Ni (alloy of approximately 42% nickel and approximately 56% iron), and isotropic 42Ni. It has been. Therefore, illustrations of the shapes of the diaphragm 23 and the support portion 33 are omitted, and description will be made using only diagrams showing the resonance frequency and the like. Also, the provision of symbols is omitted.

  FIG. 17 to FIG. 19 are diagrams showing results obtained by simulation of the resonance frequency and the like in the case of using the diaphragm and the support portion formed using the above-described materials.

  17 (a) to 17 (c) show the longitudinal resonance frequency and the bending resonance frequency when fixed, that is, when the vibrating body is fixed, and the support portion length L is changed between about 0.4 mm and about 8.0 mm. It is a figure which shows the result calculated | required. FIG. 17A is a diagram illustrating a result when anisotropic SUS301 is used as the material of the diaphragm. FIG. 17B is a diagram showing the results when anisotropic 42Ni is used as the material of the diaphragm. FIG. 17C is a diagram showing a result when isotropic 42Ni is used as the material of the diaphragm.

  The support portion length L when the longitudinal resonance frequency and the bending resonance frequency are reversed is approximately 4.5 mm for anisotropic materials (anisotropic SUS301 and anisotropic 42Ni), and isotropic materials (isotropic). 42Ni) is approximately 5.5 mm. That is, although there is a slight difference depending on the material, the whole tends to be substantially similar. The difference between the anisotropic material and the isotropic material, and the difference between SUS301 and 42Ni are the same as the support width B and the support. It can be said that the resonance frequency is not greatly affected as compared with the ratio of the part length L.

  18 (a) to 18 (c) show the longitudinal resonance frequency and the bending resonance frequency when not fixed, that is, when the vibrating body is not fixed, and when the support portion length L is between approximately 0.4 mm and approximately 8.0 mm. It is a figure which shows the result calculated | required by changing. FIG. 18A is a diagram illustrating a result when anisotropic SUS301 is used as the material of the diaphragm. FIG. 18B is a diagram showing a result when anisotropic 42Ni is used as the material of the diaphragm. FIG. 18C is a diagram showing the results when isotropic 42Ni is used as the material of the diaphragm.

  The support portion length L when the longitudinal resonance frequency and the bending resonance frequency are reversed is approximately 5.7 mm for anisotropic materials (anisotropic SUS301 and anisotropic 42Ni), and isotropic materials (isotropic). 42Ni) is approximately 6.5 mm. Although there is a slight difference depending on the material, the whole tends to be similar. Therefore, as in the case of fixing, the difference between the anisotropic material and the isotropic material, and the difference between SUS301 and 42Ni do not greatly affect the resonance frequency compared to the ratio of the support width B and the support length L. It can be said.

  19 (a) to 19 (c) show the difference between the longitudinal resonance frequency when the (vibrating body) is fixed and the longitudinal resonance frequency when not fixed, and the bending resonance frequency when fixed and the bending resonance when not fixed. It is a figure which shows the result of having calculated | required the difference with a frequency by fluctuating support part length L between about 0.4 mm-about 8.0 mm. FIG. 19A is a diagram showing a result when anisotropic SUS301 is used as the material of the diaphragm. FIG. 19B is a diagram showing the results when anisotropic 42Ni is used as the material of the diaphragm. FIG. 19C is a diagram showing a result when isotropic 42Ni is used as the material of the diaphragm.

  As shown in the figure, the influence of fluctuations in the support portion length L is greatly different between the longitudinal resonance frequency and the bending resonance frequency. The difference between when the longitudinal resonance frequency is fixed and when the three types of materials are not fixed is within approximately 2 kHz while the support portion length L varies from approximately 0.4 mm to approximately 8.0 mm. On the other hand, the difference between when the bending resonance frequency is fixed and when the bending resonance frequency is not fixed in the above three types of materials is within about 2 kHz if the support portion length L is in the range of 4.0 mm or more, but 2.0 mm to In the range of 4.0 mm, it fluctuates greatly. Even within the range of 0.4 mm to 2.0 mm, the maximum fluctuates nearly 10 kHz.

  However, the material difference is small for both the longitudinal resonance frequency and the bending resonance frequency. Similar results are shown for the above three materials. Therefore, from the viewpoint of the resonance frequency at the time of fixation and the resonance frequency at the time of non-fixation, the difference between the anisotropic material and the isotropic material and the difference between SUS301 and 42Ni are It can be said that the resonance frequency is not greatly affected compared to the ratio.

  As described above with reference to FIGS. 17 to 19, the difference in material has less influence on the resonance frequency of the vibrating body than the ratio of the support width (B) and the support length (L). Therefore, as long as the above-described ratio (approximately 1: 3 to approximately 1: 4) in the vibrating body 11 of the first embodiment or the above-described ratio (1: 1) in the vibrating body 12 of the second embodiment is maintained. The material for forming the diaphragm and the support portion formed integrally with the diaphragm can be selected from a wide range according to the usage conditions of the piezoelectric motor. Therefore, it is possible to realize a piezoelectric motor with high energy conversion efficiency, that is, a piezoelectric motor with reduced energy consumption, in a piezoelectric motor used under a wide range of conditions including the usage environment.

(Third embodiment)
Next, as a third embodiment, the piezoelectric motor 1 according to the first embodiment or the piezoelectric motor including the vibrating body, the diaphragm, and the support described in the second embodiment is configured. A robot hand including a piezoelectric motor and a robot including the robot hand will be described with reference to FIGS.

  FIG. 20 is a diagram showing an outline of a robot 200 according to the third embodiment of the present invention provided with robot hands (201, 202). The robot 200 includes a first arm 240 and a second arm 250, and a first robot hand 201 and a second robot hand 202 are disposed at the tips of the respective arms (240, 250). . The first robot hand 201 and the second robot hand 202 have substantially the same configuration. Therefore, only the first robot hand 201 (hereinafter simply referred to as “robot hand 201”) will be described below.

  FIG. 21 is a diagram showing an outline of a robot hand 201 according to the third embodiment of the present invention. As shown in FIGS. 21A and 21B, the robot hand 201 includes a palm 225, a first finger 210, and a second finger 220. The first finger 210 is composed of a first link 211 and a second link 212, and the second finger 220 is composed of a first link 221 and a second link 222. The robot hand 201 can change the link used depending on the size of the workpiece to be gripped.

  FIG. 21A shows a state where the robot hand 201 is holding a large workpiece 233. The large workpiece 233 is held by the first link 211 of the first finger 210 and the first link 221 of the second finger 220. The second link 212 of the first finger 210 is stored in the first link 211, and the second link 222 of the second finger 220 is stored in the first link 221.

FIG. 21B shows a state where the robot hand 201 is holding the small work 234. The small work 234 is held by the second link 212 of the first finger 210 and the second link 222 of the second finger 220.
As described above, the robot hand 201 can preferably grip each work (233, 234) by changing the link to be used depending on the work to be gripped. The robot hand 201 includes a plurality of piezoelectric motors as drive mechanisms for gripping the workpiece and storing the second links (212, 222).

  22A to 22D are diagrams showing an outline of the first finger 210 provided in the robot hand 201. FIG. The second finger 220 has the same configuration. FIG. 22A shows a state in which the second link 212 is stored in the groove 226 formed in the first link 211 (see FIG. 22D). FIG. 22B shows a state where the second link 212 is being taken out from the first link 211. FIG. 22C shows a state where the second link 212 is taken out from the first link 211.

Such an operation is performed around the second joint (rotating shaft) 215. The opening / closing operation of the first link 211 is performed around the first joint (rotating shaft) 213. In each joint (213, 215), a second piezoelectric motor 214 and a third piezoelectric motor 216 having the same configuration as the piezoelectric motor 1 according to the first embodiment described above are disposed as driving actuators. Has been.
As described above, the second link 212 is a link that grips the small work 234. Therefore, the third piezoelectric motor 216 can be a piezoelectric motor that is smaller and has a lower driving force than the second piezoelectric motor 214.

  As described above, the robot hand 201 uses the piezoelectric motors (214, 216) having a configuration similar to the piezoelectric motor 1 of the first embodiment as an actuator for performing a gripping operation. As described above, since the energy conversion efficiency of the piezoelectric motor 1 according to the first embodiment is improved, it is possible to reduce the electric power required for performing the same work. Further, high energy conversion efficiency means that a piezoelectric motor that exhibits the same torque or the like can be miniaturized. Therefore, the robot hand 201 of this embodiment and the robot 200 including the robot hand are reduced in size, weight, and cost. The robot 200 can perform the same work with lower power, that is, at lower cost than other robots.

Note that not only the robot hand (201, 202) but also an actuator for driving the first arm 240 and the second arm 250 is a piezoelectric having the same configuration as the piezoelectric motor 1 according to the first embodiment. A motor can be used.
Further, when the piezoelectric motor is used as an actuator for performing the gripping operation of the robot hand as described above, it is preferable to use it through an acceleration / deceleration means such as a gear. In general, since the rotation speed of the piezoelectric motor is quite fast, it may be necessary to reduce the rotation speed in accordance with the movement of the link (the first link 211 or the like). On the other hand, it may be necessary to increase the rotational speed. In such a case, the piezoelectric motor can be suitably used as an actuator of a robot hand that performs various operations by using the piezoelectric motor via speed increasing / decreasing means such as a gear.

  Various modifications of the embodiment of the present invention are possible in addition to the above-described embodiments. Hereinafter, a modification will be described.

(Modification)
In the third embodiment described above, the robot hand 201 and the robot 200 using the robot hand have been described as devices using the piezoelectric motor (1 etc.) according to the first embodiment described above. However, a device using the above-described piezoelectric motor (1 or the like) is not limited to the robot 200. It can be used as an actuator in various devices such as a clock feeding device for a clock, an IC handler, a printing device, and a medication pump.

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric motor as a piezoelectric actuator, 2 ... Base, 3 ... Rotor as driven part, 11 ... Vibrating body of 1st Embodiment, 12 ... Vibrating body of 2nd Embodiment, 13 ... Example 1 21 ... the diaphragm of the first embodiment, 22 ... the diaphragm of the second embodiment, 23 ... the diaphragm of Example 1, 25 ... the protrusion, 27 ... the through hole, 30 ... the piezoelectric element, DESCRIPTION OF SYMBOLS 31 ... Support part of 1st Embodiment, 32 ... Support part of 2nd Embodiment, 33 ... Support part of Example 1, 40 ... Piezoelectric layer, 50 ... 1st electrode, 60 ... 2nd electrode, 71 ... 1st groove part, 72 ... 2nd groove part, 80 ... Energizing means, 81 ... Holding member, 82 ... Spring member, 83 ... Supporting pin, 84 ... Fixing part, 85 ... Slide part, 86 ... Screw member, 87 ... Female thread part, 88 ... Slide hole, 89 ... Slide pin, 200 ... Robot, 201 ... First b 202 ... second robot hand 210 ... first finger 211 ... first link 212 ... second link 213 ... first joint 214 ... second piezoelectric motor 215 ... second 216 ... third piezoelectric motor, 220 ... second finger, 221 ... first link, 222 ... second link, 225 ... palm, 226 ... groove, 233 ... large work, 234 ... small work, 240 ... 1st arm, 250 ... 2nd arm.

Claims (13)

The base,
A diaphragm having a first side, a second side, a third side and a fourth side connecting between the first side and the second side;
A first support portion fixed to the base and provided in a direction substantially perpendicular to the first side from the first side;
A second support portion fixed to the base and provided in a direction substantially perpendicular to the third side from the third side;
A contact portion capable of contacting the driven portion ,
Wherein a first length of the first support portion in a direction along the first side, the ratio of the second length of the first support portion in a direction protruding from the first side is substantially 1: 0 .66 - approximately 1: are four der,
The length of the second support portion in the direction along the third side is substantially equal to the first length,
The piezoelectric actuator according to claim 1, wherein a length of the second support portion in a direction protruding from the third side is substantially equal to the second length . The piezoelectric actuator according to claim 1,
  The ratio between the first length and the second length is approximately 1: 1 to approximately 1: 4. The piezoelectric actuator according to claim 1 or 2 ,
The piezoelectric actuator according to claim 1, wherein the first side and the second side are longer than the third side and the fourth side. The piezoelectric actuator according to any one of claims 1 to 3 ,
The length of the first side and the length of the second side are substantially equal,
The piezoelectric actuator characterized in that the length of the third side and the length of the fourth side are substantially equal. The piezoelectric actuator according to any one of claims 1 to 4 , wherein the ratio is approximately 1: 1.   5. The piezoelectric actuator according to claim 1, wherein the ratio is in a range of approximately 1: 3 to approximately 1: 4. 6. The piezoelectric actuator according to any one of claims 1 to 6 , wherein
The piezoelectric actuator is characterized in that the first side has a length of about 7.0 mm and the third side has a length of about 2.0 mm. The piezoelectric actuator according to any one of claims 1 to 7 ,
The piezoelectric actuator is characterized in that the first side has a length of about 21.0 mm and the third side has a length of about 5.6 mm. The piezoelectric actuator according to any one of claims 1 to 8 ,
The piezoelectric actuator , wherein the diaphragm , the first support portion, and the second support portion are integrally formed. The piezoelectric actuator according to claim 9 , wherein
The piezoelectric actuator , wherein the diaphragm , the first support portion, and the second support portion include SUS301 or an Fe-42Ni alloy.   The piezoelectric actuator according to any one of claims 1 to 10,
  The piezoelectric actuator, wherein the diaphragm includes an anisotropic material. A robot hand comprising the piezoelectric actuator according to any one of claims 1 to 11 . A robot comprising the piezoelectric actuator according to any one of claims 1 to 12 .

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