JP2008131681A - Moving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric vibrator capable of moving an object to be moved without deteriorating a driving force of a part contacting the object to be moved. <P>SOLUTION: The piezoelectric resonator is provided with a piezoelectric element. The piezoelectric resonator has an external wall, an upper surface portion where the piezoelectric element is attached, and a sim formed by rolling. The sim has an angle of 45 degrees between the direction of rolling and a first direction of moving the object to be driven, and the object to be driven forces the external wall portion in a second direction perpendicular to the first direction. In the piezoelectric vibrator, a resonant frequency of expansion/shrinkage mode vibration of the piezoelectric vibrator is set at a value approximate to an intermediate value between first and second driving frequencies at which the amplitude of the first direction is the maximum at a point for forcing the external wall portion by the object to be driven and when a voltage is applied to the piezoelectric element while changing a driving frequency so that a bent mode vibration can be excited in a state of not exciting the expansion/shrinkage vibration. In moving the object to be driven in the first direction, AC voltage is applied using either the first or second frequency as a driving frequency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a moving device, and more particularly to a moving device that moves a driven body in an arbitrary one-dimensional direction.

There has been proposed a moving device that moves a driven body in an arbitrary one-dimensional direction using a piezoelectric vibrator. Patent Document 1 discloses a moving device that contacts a driven body at two protrusions (contact points) and switches a one-dimensional moving direction according to a frequency change.
JP 2005-261080 A

  However, in the device of Patent Document 1, one of the two protrusions does not contribute to driving, and friction hinders driving.

  Accordingly, an object of the present invention is to provide a piezoelectric vibrator that can be driven without reducing a driving force at a portion in contact with a driven body.

  A piezoelectric vibrator according to the present invention includes a piezoelectric element, an outer wall portion, and a shim made of a metal elastic plate formed by rolling and having an upper surface portion to which the piezoelectric element is attached. The shim has a first angle formed between the direction of rolling and one or the other of the first directions in which the driven body is moved, and the driven body is in a second direction perpendicular to the first direction. Then, the outer wall is urged. A driving frequency is applied to the piezoelectric element so as to excite the bending mode vibration that bends and vibrates in the first direction without exciting the stretching mode vibration that expands and contracts in the radial direction from the center of the upper surface portion to the outer wall portion. Than the first drive frequency and the first drive frequency when the voltage is applied while changing the angle, and the first peak at which the amplitude in the first direction becomes maximum at the point where the driven body urges the outer wall portion. The resonance frequency of the expansion / contraction mode vibration of the piezoelectric vibrator is set in the vicinity of an intermediate value with respect to the second drive frequency when the second peak has a high frequency and a maximum amplitude. When the driven body is moved in one direction in the first direction, an alternating voltage is applied to the piezoelectric element with a value near the first driving frequency as the driving frequency, and the bending mode vibration and expansion / contraction are applied to the piezoelectric element. When the mode vibration is excited and the driven body is moved in the other direction in the first direction, the piezoelectric element is applied with an alternating voltage having a value near the second driving frequency as a driving frequency, and is biased. The bending mode vibration and the stretching mode vibration are excited, and the first angle is a value larger than 0 degree and smaller than 90 degrees.

  Preferably, the first driving frequency is a resonance frequency of the bending mode vibration of the piezoelectric vibrator.

  Preferably, the first angle is 45 degrees.

  Also preferably, the shim is made of stainless steel.

  Preferably, the piezoelectric element is attached with first to third electrodes arranged side by side in the first direction, and at least one of the first and third electrodes applies an AC voltage for exciting bending mode vibration. The second electrode is used for applying an alternating voltage for exciting the expansion and contraction mode vibration, and is arranged at the central portion.

  Preferably, the piezoelectric element is attached with first to third electrodes arranged side by side in the first direction, and at least one of the first and third electrodes applies an AC voltage for exciting bending mode vibration. The second electrode is used for applying an alternating voltage to excite the stretching mode vibration, and is disposed on the outer peripheral portion including both end portions in the first direction.

  Preferably, the piezoelectric element is provided with first and second electrodes arranged side by side in the first direction, and at least one of the first and second electrodes excites bending mode vibration and expansion mode vibration. Used for AC voltage application.

  As described above, according to the present invention, it is possible to provide a piezoelectric vibrator that can be driven without reducing the driving force of the portion in contact with the driven body.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the first embodiment will be described. The moving device includes a movable unit having the horizontal moving unit 10 and a fixed unit having the piezoelectric vibrator 30, the fixed base 50, and the circuit unit 70 (see FIGS. 1 to 3). In order to describe the direction, in the moving device, the moving direction of the horizontal moving unit 10 is the first direction x, the urging direction of the piezoelectric vibrator 30 orthogonal to the first direction x is the second direction y, and the first A direction orthogonal to the direction x and the second direction y will be described as a third direction z.

  The horizontal movement unit (driven body) 10 includes first and second friction members 11 and 12 and a horizontal movement frame 19. The horizontal movement unit 10 is movable in the first direction x. Therefore, by fixing a member to be moved to the horizontal movement unit 10, the member can be moved in the first direction x.

  The first and second friction members 11 and 12 have a rectangular parallelepiped shape, and one of the planes perpendicular to the second direction y is in contact with the piezoelectric vibrator 30, and the horizontal moving frame 19 is caused by the vibration of the piezoelectric vibrator 30. At the same time, it is movable in the first direction x, and the other is attached inside the horizontal movement frame 19.

  The horizontal movement frame 19 is a flat frame having a rectangular hole on the inner side and perpendicular to the third direction z, and the first and second friction members 11 and 12 are attached to the inner rectangular hole, and a piezoelectric body. A vibrator 30 is arranged.

  The piezoelectric vibrator 30 includes first and second piezoelectric elements (piezoelectric ceramic rings) 31 and 32 having a hollow cylindrical shape, and a shim 34 formed of a thin metal elastic plate. The first and second piezoelectric elements 31 and 32 are fixed to the outer wall portion and the upper and lower surfaces perpendicular to the third direction z (see FIG. 2).

  Electrodes are provided on the surfaces of the first and second piezoelectric elements 31 and 32 viewed from the third direction z. The electrodes are divided into three when viewed from the third direction z, and the first, second, and third electrodes 31a, 31b, and 31c of the first piezoelectric element 31 and the fourth, fifth, and sixth electrodes of the second piezoelectric element 32 are divided. 32a, 32b, and 32c are attached. The electrode and the piezoelectric element may be attached to only one of the upper surface and the lower surface of the shim 34, but the form attached to both surfaces as in the first embodiment is more preferable. A strong driving force can be obtained.

  The first to third electrodes 31a to 31c are arranged side by side in the first direction x. The first and third electrodes 31a and 31c used for applying an alternating voltage for exciting the bending mode vibration are outer peripheral portions including an end portion in the first direction x on the shim body portion 34a (first piezoelectric element 31). The second electrode 31b used for applying an alternating voltage for exciting the expansion / contraction mode vibration is disposed at the central portion on the shim body 34a (first piezoelectric element 31). The first and third electrodes 31 a and 31 c are arranged in a positional relationship facing the center on the xy plane of the piezoelectric vibrator 30 on the xy plane.

The first electrode 31 a and the fourth electrode 32 a are arranged to face each other in the third direction z, and the first AC voltage VE ₁ having the same waveform is applied from the circuit unit 70. The second electrode 31b and the fifth electrode 32b, is disposed so as to face in a third direction z, the second AC voltage VE ₂ of the same waveform is applied from the circuit unit 70. The third electrode 31c and the sixth electrode 32c, is disposed so as to face in a third direction z, the second AC voltage VE ₂ of the same waveform is applied from the circuit unit 70.

First AC voltage VE ₁ and the second AC voltage VE ₂ are in a relationship of opposite phases. By applying the _first and second AC voltages VE ₁ and VE _{2 to} the first, third, fourth, and sixth electrodes 31a, 31c, 32a, and 32c, the piezoelectric vibrator 30 bends and vibrates in the first direction x. The bending mode vibration is excited. Second, telescopic fifth electrode 31b, the second application of the AC voltage VE ₂ to 32b, the piezoelectric vibrator 30 in the radial direction (radial direction from the upper and lower surfaces of the center of the shim body portion 34a to the outer wall portion) The stretching mode vibration is excited. The drive frequencies of the first and second AC voltages VE ₁ and VE ₂ are set to the same first drive frequency f1 or second drive frequency f2.

  The amount of movement of the horizontal movement unit 10 in the first direction x is adjusted by changing the amplification factor in the first amplifier 73a and the like and the application time to each voltage.

  The shim 34 includes a hollow cylindrical shim main body 34a in which the first and second piezoelectric elements 31 and 32 are fixed to both surfaces, and first, second, third, and fourth support portions 35a supported by the fixing base 50. 35b, 35c, and 35d (see FIGS. 2 and 3). The shim body 34 a is a cylindrical outer wall and is urged in the second direction y by the urging force of the first friction member 11 and the reaction force of the second friction member 12 against the urging force of the first friction member 11. . The first, second, third, and fourth support portions 35a, 35b, 35c, and 35d are portions protruding from the shim main body portion 34a, and the fixing member 53 is inserted into the holes of the first support portion 35a, 35b, 35c, and 35d. It is attached. Accordingly, the piezoelectric vibrator 30 including the shim 34 is fixed to the fixed base 50 and does not move. On the other hand, the horizontal movement unit 10 can move in the first direction x by the vibration of the piezoelectric vibrator 30.

  The shim 34 is made of stainless steel (stainless steel containing 18% Cr and 8% Ni: SUS304). The shim main body 34a of the shim 34 is attached in a state where the rolling direction has one angle (positive direction) or the other (negative direction) of the first direction x having the first angle θ1. The first angle θ1 is preferably 45 degrees (that is, the angle formed with the first direction x is 45 degrees or 135 degrees) (see FIG. 4).

In a state where no voltage is applied to each electrode, the first and second piezoelectric elements 31 and 32 are stationary without causing deformation. First, fourth electrode 31a, the first AC voltage VE ₁ is applied in 32a, third, sixth electrode 31c, the second AC voltage VE ₂ is applied to 32c, the piezoelectric vibrator 30, the A bending mode vibration (bending vibration in the driving direction in which the center hole of the shim 34 reciprocates in the first direction x) that excites in one direction x is excited. When the second, fifth electrode 31b, a second AC voltage VE ₂ to 32b is applied, the piezoelectric vibrator 30, the radial (radial direction from the upper and lower surfaces of the center of the shim body portion 34a to the outer wall portion) Stretching mode vibration (longitudinal vibration in which the central hole of the shim 34 repeats expansion and contraction) is excited. The portions of the outer wall of the shim body 34a that are in contact with the first and second friction members 11 and 12 due to the bending mode vibration and the expansion and contraction mode vibration (the shim body 34a of the first and second friction members 11 and 12 are The portion that urges the outer wall portion in the second direction y) performs an elliptical motion.

  Due to this elliptical motion, the first and second friction members 11 and 12 that contact the outer wall portion of the shim body 34 a in a state in which the outer wall portion is biased in the second direction y are The horizontal movement unit 10 is moved in the first direction x along with the movement in the first direction x.

By adjusting the dimensional ratio between the inner diameter and the outer diameter of the piezoelectric vibrator 30, the resonance frequency f _R of the vibration in the radial direction (longitudinal vibration) and the vibration frequency (the transverse vibration) resonance frequency f _{X in the} driving direction are determined. . In the first embodiment, the resonance frequency f _R of the vibration in the radial direction, first, the size ratio is set to be an intermediate value of the second driving frequency f1, f2.

While changing the driving frequency, only the first and second AC voltages VE ₁ and VE ₂ are applied to the first, third, fourth, and sixth electrodes 31a, 31c, 32a, and 32c. electrode 31b, in a state of not performing a second voltage application of the AC voltage VE ₂ to 32 b (the bending mode vibration in the first direction to excite, when no exciting stretching mode vibration in the radial direction), the outer wall of the shim body portion 34a Drive the _first and second AC voltages VE ₁ and VE ₂ when the amplitude of the portion in contact with the first and second friction members 11 and 12 shows two peaks (maximum points) in the first direction x The frequency to be set is set to the first and second drive frequencies f1 and f2. FIG. 5 shows the relationship between the amplitude of the portion of the outer wall portion of the shim body portion 34a that contacts the first friction member 11 and the driving frequency. In the first embodiment, the frequency when the amplitude of the higher peak (first peak) is shown is the first frequency f1 (= resonance frequency f _{X of} transverse vibration), and the amplitude of the lower peak (second peak) is shown. The frequency when shown is set as the second frequency f2 (> first frequency f1).

When the first and second AC voltages VE ₁ and VE ₂ are applied at the first drive frequency f1, the phase of the expansion / contraction mode vibration is about 90 degrees ahead of the phase of the bending mode vibration, When voltage application of the first and second AC voltages VE ₁ and VE ₂ is performed at the two drive frequencies f2, the phase of the bending mode vibration advances about 90 degrees compared to the phase of the expansion / contraction mode vibration. For this reason, the elliptical orbit at the point of contact with the first and second friction members 11 and 12 on the outer wall portion of the shim body 34a has the first drive frequency f1 and the first and second AC voltages VE ₁ , When the voltage of VE ₂ is applied and when the voltages of the first and second AC voltages VE ₁ and VE ₂ are applied at the second drive frequency f2, the rotation is in the opposite direction.

Therefore, by switching the driving frequency of the first and second AC voltages VE ₁ and VE ₂ between the first driving frequency f1 and the second driving frequency f2, the horizontal direction moving unit 10 is moved in the first direction x and to each other. It becomes possible to move in the reverse direction. This eliminates the need to switch the drive electrode or phase in order to reverse the drive direction, thus simplifying the circuit configuration.

  In the first embodiment, the point of contact (biasing) with the outer wall portion of the shim body 34a of the first and second friction members 11 and 12 is elliptically excited by bending vibration and stretching vibration. Contribute to driving. Therefore, when driving, the contacting portion does not hinder the driving force, and the movement control can be performed efficiently.

  The fixed base 50 includes a fixed base main body 50 a, an engagement member (not shown) that supports the horizontal movement unit 10 slidably in the first direction x, and a fixing member 53 that fixes the piezoelectric vibrator 30. .

  The circuit unit 70 includes a drive signal generation unit 71, a phase inverter 72, and first and second amplifiers 73a and 73b (see FIG. 6).

  The drive signal generator 71 outputs a sine wave having the first drive frequency f1 or the second drive frequency f2 in a state where the output time (application time of AC voltage) is adjusted. The drive frequency of the sine wave output from the drive signal generator 71 is the first drive frequency f1 or the second drive frequency f2 depending on the direction in which the horizontal direction moving unit 10 is moved (any direction of the first direction x). Can be switched to. The drive signal generator 71 is connected to the second amplifier 73b and the phase inverter 72. The phase inverter 72 inverts the phase of the drive signal output from the drive signal generator 71. The phase inverter 72 is connected to the first amplifier 73a.

The first amplifier 73a, the first for exciting a bending mode vibration, the fourth electrode 31a, is connected to 32a, to adjust the amplitude of the AC voltage applied as the first AC voltage VE _1. The second amplifier 73b, the second to excite the stretching mode vibration, the fifth electrode 31b, is connected to the 32b, adjusts the amplitude of the AC voltage applied as the second AC voltage VE _2. The second amplifier 73b, the third for exciting a bending mode vibration, the sixth electrode 31c, connected to the 32c, to adjust the amplitude of the AC voltage applied as the second AC voltage VE _2.

  However, the phase inverter 72 and the first amplifier 73a may not be provided, and an AC voltage may not be applied to the first and fourth electrodes 31a and 32a (see FIG. 9).

  Next, a second embodiment will be described (see FIG. 7). The second embodiment is different from the first embodiment in the arrangement of the first to third electrodes 31a to 31c and the fourth to sixth electrodes 32a to 32c.

  First and third electrodes 31a and 31c for exciting the bending mode vibration are arranged in the first direction x, and a second for exciting the expansion and contraction mode vibration on the outer periphery of the first and third electrodes 31a and 31c. An electrode 31b is disposed. The second electrode 31b is disposed on the outer periphery including the end portion in the first direction x on the shim main body 34a (first piezoelectric element 31), and the first and third electrodes 31a and 31c are connected to the shim main body 34a ( The first piezoelectric element 31) is disposed in the center portion. The first and third electrodes 31 a and 31 c are arranged in a positional relationship facing the center on the xy plane of the piezoelectric vibrator 30 on the xy plane.

  Other forms such as the positional relationship between the first to third electrodes 31a to 31c and the fourth to sixth electrodes 32a to 32c are the same as those of the first embodiment, and the phase inverter 72 and the first amplifier 73a are provided. There may be a form in which an AC voltage is not applied to the first and fourth electrodes 31a and 32a without being provided (see FIG. 10).

  Next, a third embodiment will be described (see FIG. 8). The third embodiment is different from the first embodiment in the electrode arrangement and the configuration of the circuit unit 70.

  Electrodes are provided on the surfaces of the first and second piezoelectric elements 31 and 32 viewed from the third direction z. The electrodes are divided into two when viewed from the third direction z, and the first and second electrodes 310a and 310b of the first piezoelectric element 31 and the third and fourth electrodes 320a and 320b of the second piezoelectric element 32 are attached.

  The first and second electrodes 310a and 310b are arranged side by side in the first direction x. The first and second electrodes 310a and 310c are arranged from the outer peripheral portion including the end portion in the first direction x on the shim main body portion 34a (first piezoelectric element 31) to the center portion. The first and second electrodes 310a and 310b are arranged in a positional relationship facing the center on the xy plane of the piezoelectric vibrator 30 on the xy plane.

  The first electrode 310a and the third electrode 320a are arranged to face each other in the third direction z, and no AC voltage is applied. The second electrode 310b and the fourth electrode 320b are arranged to face each other in the third direction z, and an AC voltage VE having the same waveform is applied from the circuit unit 70 to excite bending mode vibration and expansion / contraction mode vibration. .

  The circuit unit 70 includes a drive signal generation unit 71 and an amplifier 73.

  The drive signal generator 71 outputs a sine wave having the first drive frequency f1 or the second drive frequency f2 in a state where the output time (application time of AC voltage) is adjusted. The drive frequency of the sine wave output from the drive signal generator 71 is the first drive frequency f1 or the second drive frequency f2 depending on the direction in which the horizontal direction moving unit 10 is moved (any direction of the first direction x). Can be switched to. The drive signal generator 71 is connected to the amplifier 73.

  The amplifier 73 adjusts the amplitude of the AC voltage VE. The AC voltage VE output from the amplifier 73 is applied to the first, second, and fourth electrodes 310b and 320b.

  Other configurations are the same as those of the first embodiment.

  In the first to third embodiments, the first and second piezoelectric elements 31, 32 and the shim main body 34a are preferentially considered in consideration of downsizing of the apparatus and improvement of driving efficiency of the piezoelectric vibrator. However, it is possible to move in a one-dimensional manner even if the shape is a multiple of 4 and other shapes such as a regular m square or a cylindrical shape are used. In addition, even if the drive signals are provided in two systems (the number of input signals is 2, see FIGS. 6 and 7), one system (the number of input signals is 1, FIG. To 10) may be provided.

  Further, the first angle θ1 indicating the angle between the rolling direction of the shim 34 and one or the other of the first direction x is preferably 45 degrees, but other angles (90 degrees larger than 0 degrees and 90 degrees). Smaller angle). However, as the distance from 45 degrees increases, the amplitude of the second peak decreases, the driving force at the second driving frequency f2 decreases, and the difference from the driving force at the first driving frequency f1 also increases.

  In addition, the frequency of the sine wave from the drive signal generator 71 (AC voltage drive frequency) has been described as being set to one of the first and second drive frequencies f1 and f2, but in order to adjust the movement amount, A value different from the first and second drive frequencies f1 and f2 (a value in the vicinity of the first and second drive frequencies f1 and f2, and a phase difference between the excited stretching mode vibration and the bending mode vibration is not zero). A frequency may be used. In this case, the closer the frequency is to the first and second drive frequencies f1 and f2, the greater the driving force is obtained, and a larger amount of movement is obtained. The farther away the frequency is, the smaller the driving force is, and the smaller the amount of movement is.

It is a perspective view which shows the structure of the horizontal direction movement part in 1st-3rd embodiment, and a piezoelectric material vibrator. 1 is a configuration diagram of a piezoelectric vibrator in a first embodiment. FIG. It is a block diagram of the cross section in the AA line of FIG. It is a figure which shows the rolling direction of a shim. Only the drive frequency and the first and second AC voltages are applied to the first, third, fourth, and sixth electrodes, and the second AC voltage is not applied to the second and fifth electrodes. It is a graph which shows the relationship with the amplitude of the 1st direction of the part which contacts a 1st, 2nd friction member in the outer wall part of a shim main-body part in a state. It is a block diagram of the circuit part and electrode in 1st Embodiment. It is a block diagram of the circuit part and electrode in 2nd Embodiment. It is a block diagram of the circuit part and electrode in 3rd Embodiment. FIG. 3 is a configuration diagram of a circuit unit and electrodes in the first embodiment, and is a diagram in which an AC voltage is not applied to the first and fourth electrodes. It is a block diagram of the circuit part and electrode in 2nd Embodiment, and is a figure of the form which does not perform alternating voltage application to the 1st, 4th electrode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Horizontal direction moving part 11, 12 1st, 2nd friction member 19 Horizontal direction moving frame 30 Piezoelectric vibrator | oscillator 31, 32 1st, 2nd piezoelectric element 31a, 31b, 31c 1st, 2nd, 3rd electrode ( First and second embodiments)
32a, 32b, 32c Fourth, fifth and sixth electrodes (first and second embodiments)
310a, 310b First and second electrodes (third embodiment)
320a, 320b Third and fourth electrodes (third embodiment)
34 shim 34a shim main body 35a, 35b, 35c, 35d first, second, third, fourth support 50 fixed base 50a fixed base main body 53 fixing member 70 circuit part 71 drive signal generating part 72 phase inverter 73 Amplifiers 73a and 73b First and second amplifiers VE ₁ and VE ₂ First and second AC voltages θ1 First angle

Claims (7)

A piezoelectric element;
A piezoelectric vibrator having an outer wall portion and an upper surface portion to which the piezoelectric element is attached, and a shim composed of a rolled metal elastic plate,
The shim has a first angle formed between the direction in which the rolling is formed and one or the other of the first direction in which the driven body is moved,
The driven body urges the outer wall portion in a second direction perpendicular to the first direction,
The piezoelectric vibrator is excited so as to excite bending mode vibration that bends and vibrates in the first direction without exciting expansion and contraction mode vibration that expands and contracts in the radial direction from the center of the upper surface portion to the outer wall portion. The first driving when a voltage is applied to the piezoelectric element while changing the driving frequency, and when the driven body shows a first peak at which the amplitude in the first direction becomes maximum at a point where the driven body urges the outer wall portion. Resonance of the stretching mode vibration of the piezoelectric vibrator is in the vicinity of an intermediate value between a frequency and a second driving frequency that is higher than the first driving frequency and has a second peak at which the amplitude is maximum. Frequency is set,
When the driven body is moved in one of the first directions, an AC voltage is applied to the piezoelectric element with a value near the first driving frequency as a driving frequency, and the biasing is performed. The bending mode vibration and the stretching mode vibration are excited,
When the driven body is moved in the other direction of the first direction, an AC voltage is applied to the piezoelectric element with a value near the second driving frequency as a driving frequency. The bending mode vibration and the stretching mode vibration are excited,
The piezoelectric vibrator according to claim 1, wherein the first angle is greater than 0 degrees and smaller than 90 degrees.   2. The piezoelectric vibrator according to claim 1, wherein the first drive frequency is a resonance frequency of the bending mode vibration of the piezoelectric vibrator.   The piezoelectric vibrator according to claim 1, wherein the first angle is 45 degrees.   The piezoelectric vibrator according to claim 1, wherein the shim is made of stainless steel. The piezoelectric element is attached with first to third electrodes arranged side by side in the first direction,
At least one of the first and third electrodes is used for applying an alternating voltage for exciting the bending mode vibration, and is disposed on an outer peripheral portion including both end portions in the first direction x.
2. The piezoelectric vibrator according to claim 1, wherein the second electrode is used for applying an alternating voltage to excite the expansion / contraction mode vibration, and is disposed in a central portion. The piezoelectric element is attached with first to third electrodes arranged side by side in the first direction,
At least one of the first and third electrodes is used for applying an alternating voltage to excite the bending mode vibration, and is disposed in a central portion.
2. The piezoelectric vibration according to claim 1, wherein the second electrode is used for applying an alternating voltage to excite the stretching mode vibration, and is disposed on an outer peripheral portion including both end portions in the first direction. Child. First and second electrodes arranged side by side in the first direction are attached to the piezoelectric element,
2. The piezoelectric vibrator according to claim 1, wherein at least one of the first and second electrodes is used for applying an alternating voltage for exciting the bending mode vibration and the expansion / contraction mode vibration.

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