WO2012165189A1

WO2012165189A1 - Piezoelectric motor and piezoelectric motor device

Info

Publication number: WO2012165189A1
Application number: PCT/JP2012/062905
Authority: WO
Inventors: 浅野宏志
Original assignee: 株式会社村田製作所
Priority date: 2011-05-27
Filing date: 2012-05-21
Publication date: 2012-12-06

Abstract

To provide a piezoelectric motor and a piezoelectric motor device having a simple configuration with high power transmission efficiency and less occurrence of kinetic friction. A piezoelectric motor device (1) comprises a piezoelectric plate (2), a protrusion part (2A), and a drive part. The piezoelectric plate (2) has a first surface that includes a first area and a second area adjacent to each other. The protrusion part (2A) is provided on a boundary line between the first area and the second area, displaces in the Y axial direction along the boundary line, and displaces in the X axial direction perpendicular to the Y axial direction and the normal direction of the first surface of the piezoelectric plate (2). The drive part includes an individual electrode (3A) provided in the first area, an individual electrode (3B) provided in the second area, and a common electrode (4) provided on a second surface facing the first surface of the piezoelectric plate (2), and an AC voltage is applied between the individual electrode (3A) and the common electrode (4) so that the individual electrode (3B) does not become a floating electrode.

Description

Piezoelectric motor and piezoelectric motor device

The present invention relates to a piezoelectric motor that displaces a power transmission unit by utilizing deformation of a piezoelectric plate, and a piezoelectric motor device that converts the displacement of the power transmission unit into power of rotational motion or linear motion.

Piezoelectric motors are motors powered by the displacement of the power transmission section accompanying the deformation of the piezoelectric plate. In addition, the piezoelectric motor device converts the power of the piezoelectric motor into rotational motion or linear motion and uses it as power.

FIG. 1 is a diagram illustrating a basic configuration of a piezoelectric motor device 101 with reference to Patent Document 1. FIG. 1A is a perspective view of the piezoelectric motor device 101. FIG. 1B is a circuit diagram of the piezoelectric motor device 101. FIG. 1C is a partially enlarged plan view of the piezoelectric motor device 101. In the figure, the orthogonal direction with the normal direction of the main surface of the piezoelectric plate 102 included in the piezoelectric motor device 101 as the Z-axis direction, the longitudinal direction of the main surface as the X-axis direction, and the short direction of the main surface as the Y-axis direction. A coordinate system is added.

The piezoelectric motor device 101 includes a piezoelectric plate 102,

individual electrodes

103A and 103B, a common electrode 104, an AC source 105A, a switch 105B, a pressing spring 106, a frame 107, a bearing 108, and a linear slider 109. The piezoelectric plate 102, the

individual electrodes

103A and 103B, the common electrode 104, the AC source 105A, and the switch 105B constitute a piezoelectric motor.

The piezoelectric plate 102 is a flat plate having a rectangular main surface facing the Z-axis, and a protrusion 102A is provided on the side surface in the positive Y-axis direction. The

individual electrodes

103A and 103B are provided on the front main surface of the piezoelectric plate 102 in line symmetry with respect to a straight line along the Y-axis direction passing through the position where the protrusion 102A is provided. The common electrode 104 is provided on substantially the entire back main surface of the piezoelectric plate 102. The AC source 105A is connected between the common electrode 104 and the switch 105B, and the

individual electrodes

103A and 103B are selectively connected to the AC source 105A by the switch 105B.

A linear slider 109 is disposed in the Y axis positive direction of the piezoelectric plate 102, and a bearing 108 is disposed in the Y axis positive direction of the linear slider 109. A pressing spring 106 is disposed in the negative Y-axis direction of the piezoelectric plate 102. The pressing spring 106 is supported by the frame 107 and presses the piezoelectric plate 102 toward the linear slider 109.

When the individual electrode 103A is connected to the AC source 105A by the switch 105B and an AC voltage is applied between the individual electrode 103A and the common electrode 104 by the AC source 105A, the piezoelectric plate 102 is deformed in the XY plane, and the protrusion The part 102A is displaced by a linear reciprocating orbit having a predetermined inclination with respect to the X axis and the Y axis.

The projecting portion 102A displaced as described above collides with the side surface of the linear slider 109 in the negative Y-axis direction, whereby the power in the negative X-axis direction is transmitted from the projecting portion 102A to the linear slider 109, and the linear slider 109 is transmitted to the X-axis. It can be moved in the negative direction. By switching the switch 105B and connecting the individual electrode 103B to the AC source 105A, the moving direction of the linear slider 109 can be switched to the reverse direction.

Special table 2007-538484

In the above configuration, dynamic friction occurs and energy loss occurs when the contact pressure between the protrusion 102A and the linear slider 109 is small. Therefore, the power in the X-axis direction transmitted from the protrusion 102A to the linear slider 109 is reduced, and the power is not efficiently transmitted.

Therefore, an object of the present invention is to provide a piezoelectric motor and a piezoelectric motor device having a simple configuration in which dynamic friction hardly occurs and power transmission efficiency is high.

The piezoelectric motor according to the present invention includes a piezoelectric plate, a power transmission unit, and a drive unit. The piezoelectric plate has a first surface including a first region and a second region adjacent to each other. The power transmission unit is provided on a boundary line between the first region and the second region, and is displaced in a first direction along the boundary line, and is also in a direction normal to the first surface of the piezoelectric plate and the first direction. It is displaced in a second direction perpendicular to the direction of. The drive unit is provided on the first individual electrode provided in the first region, the second individual electrode provided in the second region, and the second surface facing the first surface of the piezoelectric plate. An AC voltage is applied between the first individual electrode and the common electrode, and the second individual electrode is prevented from becoming a floating electrode.

In this configuration, the power transmission unit provided on the boundary line between the first region and the second region is displaced by a circular or elliptical orbit, not a linear reciprocating orbit.

In the piezoelectric motor according to the present invention, the drive unit has one side connected to the first individual electrode, the other side connected to the second individual electrode and the common electrode, and the first individual electrode and the common electrode. The second individual electrode, the common electrode, and the other side of the AC source are preferably connected to the ground. In particular, it is preferable that the drive unit applies an AC voltage corresponding to a resonance frequency whose vibration mode is the E (3,1) mode between the first individual electrode and the common electrode. Further, the drive unit simultaneously excites the symmetric mode vibration of the E (3,1) mode and the vibration of the asymmetric mode on the entire piezoelectric plate, and the phase difference between the symmetric mode of the E (3,1) mode and the asymmetric mode. It is preferable to apply an AC voltage between the first individual electrode and the common electrode so that is 90 °.

In the piezoelectric motor according to the present invention, the driving unit includes an AC source that applies an AC voltage between the first individual electrode or the second individual electrode and the common electrode, and one side of the AC source is the first source. Connected to the individual electrode, the other side is connected to the second individual electrode and the common electrode, and the second individual electrode, the common electrode and the other side of the AC source are connected to the ground; One side of the AC source is connected to the second individual electrode, the other side is connected to the first individual electrode and the common electrode, and the first individual electrode, the common electrode, and the other side of the AC source are grounded. It is preferable to provide a switch for switching between the state connected to the. In particular, it is preferable that the drive unit applies an AC voltage corresponding to a resonance frequency whose vibration mode is the E (3,1) mode between the first individual electrode or the second individual electrode and the common electrode. . Further, the drive unit simultaneously excites the symmetric mode vibration of the E (3,1) mode and the vibration of the asymmetric mode on the entire piezoelectric plate, and the phase difference between the symmetric mode of the E (3,1) mode and the asymmetric mode. It is preferable to apply an AC voltage between the first individual electrode or the second individual electrode and the common electrode so that the angle is about 90 °.

In the piezoelectric motor according to the present invention, the drive unit has one side connected to the first individual electrode, the other side connected to the common electrode, and an alternating current between the first individual electrode and the common electrode. A first AC source for applying a voltage, one side is connected to a second individual electrode, the other side is connected to a common electrode, and an AC voltage is applied between the second individual electrode and the common electrode It is preferable that the other side of the first AC source and the other side of the second AC source are connected to the ground. In particular, the drive unit corresponds to a resonance frequency in which the vibration mode is the E (3,1) mode between the first individual electrode and the common electrode and between the second individual electrode and the common electrode. It is preferable to apply an alternating voltage. Further, the drive unit simultaneously excites the symmetric mode vibration of the E (3,1) mode and the vibration of the asymmetric mode on the entire piezoelectric plate, and the phase difference between the symmetric mode of the E (3,1) mode and the asymmetric mode. It is preferable to apply an AC voltage between the first individual electrode and the common electrode and between the second individual electrode and the common electrode so that the angle is about 90 °.

The piezoelectric motor device according to the present invention preferably includes any one of the above-described piezoelectric motors and a power conversion unit disposed on the first direction side of the piezoelectric plate. The power conversion unit may be a linear slider that is movable with the second direction as the movement direction.

In these configurations, a power conversion unit such as a linear slider can be driven by a piezoelectric motor, and the feed motion of the piezoelectric motor can be converted into a linear motion or the like to be used as power.

According to the present invention, since the power transmission unit is displaced so as to draw a circular or elliptical orbit instead of a linear reciprocating orbit, when the power transmission unit is largely displaced in the first direction (Y axis), the second The displacement in the direction (X axis) is small, and after the displacement in the first direction (Y axis) is small, the displacement in the second direction (X axis) is large. Therefore, when this power transmission part collides with the power conversion part which opposes a 2nd direction (Y-axis), it becomes difficult to produce dynamic friction, and wear and energy loss with a power transmission part and a power conversion part can be suppressed.

It is a figure explaining the basic composition of a piezoelectric motor device. It is a figure explaining the structure of the piezoelectric motor apparatus which concerns on the 1st Embodiment of this invention. It is a figure explaining the displacement vector of the piezoelectric plate of the piezoelectric motor apparatus which concerns on the 1st Embodiment of this invention. It is a figure explaining the displacement vector of the piezoelectric plate of the comparative example which concerns on a conventional structure. It is a circuit diagram of the piezoelectric motor device concerning a 2nd embodiment of the present invention. FIG. 6 is a circuit diagram of a piezoelectric motor device according to a third embodiment of the present invention.

FIG. 2 is a diagram illustrating the configuration of the piezoelectric motor device 1 according to the first embodiment of the present invention. FIG. 2A is a perspective view of the piezoelectric motor device 1. FIG. 2B is a circuit diagram of the piezoelectric motor device 1. FIG. 2C is a partially enlarged plan view of the piezoelectric motor device 1. In the figure, the orthogonal direction with the normal direction of the main surface of the piezoelectric plate 2 included in the piezoelectric motor device 1 as the Z-axis direction, the longitudinal direction of the main surface as the X-axis direction, and the short direction of the main surface as the Y-axis direction A coordinate system is added.

The piezoelectric motor device 1 includes a piezoelectric plate 2,

individual electrodes

3A and 3B, a common electrode 4, an AC source 5, a pressing spring 6, a frame 7, a bearing 8, and a linear slider 9.

The piezoelectric plate 2, the

individual electrodes

3A and 3B, the common electrode 4, and the AC source 5 constitute the piezoelectric motor in this embodiment, and the

individual electrodes

3A and 3B, the common electrode 4, and the AC source 5 are driving units in this embodiment. Configure. The linear slider 9 is a power conversion unit in the present embodiment.

Piezoelectric plate 2 is a flat plate having a main surface facing the Z-axis having a rectangular shape, and the main surface facing the Z-axis includes a first region and a second region adjacent to each other. A protrusion 2A is provided on the side surface in the positive direction of the Y axis on the boundary line between the first region and the second region of the piezoelectric plate 2. The protrusion 2A is a power transmission unit in the present embodiment.

The

individual electrodes

3A and 3B are provided on the main surface of the piezoelectric plate 2 facing the Z axis. The

individual electrodes

3A and 3B are provided symmetrically with respect to a straight line along the Y-axis direction that passes through the position where the protrusion 2A is provided. Specifically, the individual electrode 3A is provided in the first region, and the individual electrode 3B is provided in the second region. The common electrode 4 is provided on substantially the entire main surface facing the main surface facing the Z axis of the piezoelectric plate 2. The AC source 5 has one side connected to the individual electrode 3 </ b> A and the other side connected to the individual electrode 3 </ b> B and the common electrode 4. A connection point of the AC source 5, the individual electrode 3B, and the common electrode 4 is connected to the ground. That is, the individual electrode 3B, the common electrode 4, and the other side of the AC source 5 are connected to the ground.

The frame 7 has ribs that rise in the positive direction of the Z-axis from the XY plane at both ends of the Y-axis.

A linear slider 9 is disposed in the positive direction of the Y axis of the piezoelectric plate 2. The linear slider 9 has a rectangular bar-like configuration with the X-axis direction as the longitudinal direction. A bearing 8 is disposed in the positive direction of the Y-axis of the linear slider 9. The bearing 8 is in rolling contact with a linear slider 9 that moves in the X-axis direction. A pressing spring 6 is disposed in the negative Y-axis direction of the piezoelectric plate 2. The pressing spring 6 is supported by the rib of the frame 7 and presses the piezoelectric plate 2 toward the linear slider 9.

In this configuration, an AC voltage corresponding to a resonance frequency whose vibration mode is the E (3, 1) mode is applied between the individual electrode 3A and the common electrode 4, so that E (3 1) The vibration of the asymmetric mode of the mode is excited. At this time, since the individual electrode 3B is connected to the ground and does not become a floating electrode, an inflow of electric charge from the ground to the individual electrode 3B or an outflow of electric charge from the individual electrode 3B to the ground occurs. E (3, 1) mode symmetric mode vibrations are excited. The symmetric mode of the E (3,1) mode has substantially the same resonance frequency as the asymmetric mode of the E (3,1) mode. That is, an AC voltage corresponding to a resonance frequency whose vibration mode is the E (3,1) mode is applied between the individual electrode 3A and the common electrode 4, so that E (3,1) is applied to the entire piezoelectric plate 2. ) The symmetric mode vibration and the asymmetric mode vibration are excited simultaneously. A phase difference between the symmetric mode of the E (3,1) mode and the asymmetric mode results in a phase difference between the symmetric mode and the asymmetric mode of the E (3,1) mode. By applying an AC voltage between the individual electrode 3A and the common electrode 4 so that the angle is about 90 °, the E (3, 1) mode symmetric mode vibration and the asymmetric mode vibration are synthesized. The vibration of the elliptical motion is excited.

FIG. 3 is a diagram for explaining the displacement vector of the piezoelectric plate 2 of the piezoelectric motor device 1 according to this embodiment. Here, a sine wave signal is applied to the individual electrode 3A in the right hand region of the piezoelectric plate 2 on the right side in the drawing, and the individual electrode 3B in the left hand region of the piezoelectric plate 2 on the left side in the drawing is connected to the ground together with the common electrode 4. The example which analyzed the displacement vector by the finite element method about the structure which has been shown is shown.

When the phase of the sine wave signal is 0 °, a displacement vector in the contraction direction is generated in the right hand region of the piezoelectric plate 2, and a displacement vector in the expansion direction is generated in the left hand region. Then, in the vicinity of the protrusion 2A provided at the boundary between the right hand region and the left hand region, a displacement vector of about 45 ° is generated counterclockwise with respect to the positive direction of the X axis.

When the phase of the sine wave signal is 45 °, a displacement vector having a larger contraction direction is generated in the right-hand region of the piezoelectric plate 2 than in the case where the phase is 0 °, and the expansion direction is smaller in the left-hand region than when the phase is 0 °. The displacement vector is generated. In the vicinity of the protrusion 2A, a displacement vector in the direction of about 0 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 90 °, the displacement vector in the maximum contraction direction is generated in the right-hand region of the piezoelectric plate 2 than in the case of 45 °, and in the left-hand region, the phase is 45 °. A small expansion direction displacement vector is generated. In the vicinity of the protrusion 2A, a displacement vector in the direction of about 315 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 135 °, a displacement vector in the contraction direction is smaller in the right hand region of the piezoelectric plate 2 than in the case where the phase is 90 °, and a displacement vector in the contraction direction is generated in the left hand region. In the vicinity of the protrusion 2A, a displacement vector in a direction of about 270 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 180 °, a displacement vector in the expansion direction is generated in the right-hand region of the piezoelectric plate 2, and a displacement vector in the contraction direction is generated in the left-hand region, compared to when the phase is 135 °. In the vicinity of the protrusion 2A, a displacement vector in the direction of about 225 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 225 °, a displacement vector in the expansion direction that is larger in the right-hand region of the piezoelectric plate 2 than in the case of 180 ° is generated, and in the left-hand region, the phase is larger than that in the case of 180 °. The displacement vector in the contraction direction of In the vicinity of the protrusion 2A, a displacement vector in the direction of about 180 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 270 °, the displacement vector in the maximum extension direction is generated in the right-hand region of the piezoelectric plate 2 than in the case of 225 °, and the displacement vector in the maximum expansion direction is generated, and in the left-hand region, the phase is 225 °. A small contraction direction displacement vector is generated. In the vicinity of the protrusion 2A, a displacement vector in the direction of about 135 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 315 °, a displacement vector in the expansion direction smaller than that in the right-hand region of the piezoelectric plate 2 than in the case of 270 ° is generated, and a displacement vector in the expansion direction is generated in the left-hand region. In the vicinity of the protrusion 2A, a displacement vector of about 90 ° is generated counterclockwise with respect to the positive X-axis direction.

Although the piezoelectric plate 2 is deformed as described above, an AC voltage is applied between the individual electrode 3A and the common electrode 4 so that the phase difference between the symmetric mode and the asymmetric mode of the E (3,1) mode is about 90 °. Is applied, vibration of an elliptical motion in which a symmetric mode and an asymmetric mode of the E (3,1) mode are combined is generated, and a protrusion provided at the boundary between the left hand region and the right hand region of the piezoelectric plate 2 The displacement vector of the part 2A rotates clockwise. For this reason, the projection 2A is displaced so as to draw a clockwise circular or elliptical orbit. In other words, the protrusion 2A is displaced in the Y-axis direction and is displaced in the X-axis direction. As a result, in the piezoelectric motor device 1 described above, the projection 2A collides with the side surface of the linear slider 9 in the Y-axis negative direction, so that power in the X-axis positive direction is transmitted from the projection 2A to the linear slider 9. The slider 9 moves in the positive direction of the X axis.

Since the protrusion 2A is displaced in a circular or elliptical orbit as described above, when the protrusion 2A is largely displaced along the Y axis, the displacement along the X axis is small and the protrusion 2A is large along the Y axis. After the displacement, the displacement greatly occurs along the X axis. Therefore, in the configuration of the present embodiment, the dynamic friction between the protrusion 2A and the linear slider 9 hardly occurs, wear and energy loss of both can be suppressed, and the power transmission efficiency from the protrusion 2A to the linear slider 9 can be enhanced.

In the following, the piezoelectric motor device 101 according to the conventional configuration shown in FIG. 1 is prepared as a comparative example, and the deformation of the piezoelectric plate 102 of the piezoelectric motor device 101 according to the conventional configuration will be described. FIG. 4 is a diagram for explaining a displacement vector of the piezoelectric plate 102 of the piezoelectric motor device 101 according to the conventional configuration. Here, a finite element is applied to a configuration in which a sine wave signal is applied to the individual electrode 103A in the right hand region of the piezoelectric plate 102 on the right side in the drawing and the individual electrode 103B in the left hand region of the piezoelectric plate 102 on the left side in the drawing is in an open state. The example which analyzed the displacement vector by the method is shown.

When the phase of the sine wave signal is 0 °, a displacement vector in the expansion direction is generated in the right-hand region of the piezoelectric plate 102, but almost no displacement vector is generated in the left-hand region. Then, in the vicinity of the protrusion 102A provided at the boundary between the right hand region and the left hand region, a displacement vector in a direction of about 135 ° is generated counterclockwise with respect to the positive direction of the X axis.

When the phase of the sine wave signal is 45 °, a displacement vector in the contraction direction is generated in the right hand region of the piezoelectric plate 102, but almost no displacement vector is generated in the left hand region. In the vicinity of the protrusion 102A, a displacement vector in the direction of about 315 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 90 °, a displacement vector having a larger contraction direction is generated in the right-hand region of the piezoelectric plate 102 than in the case where the phase is 45 °, but almost no displacement vector is generated in the left-hand region. Then, in the vicinity of the protrusion 102A, a displacement vector having a direction of about 315 ° larger than the case where the phase is 45 ° is generated counterclockwise with respect to the positive direction of the X axis.

When the phase of the sine wave signal is 135 °, the phase in the right hand region of the piezoelectric plate 102 is larger than that in the case of 90 °, and a displacement vector in the maximum contraction direction is generated, but almost no displacement vector is generated in the left hand region. In the vicinity of the protrusion 102A, a displacement vector having a maximum direction of about 315 ° is generated counterclockwise with respect to the positive direction of the X axis as compared with the case where the phase is 90 °.

When the phase of the sine wave signal is 180 °, a displacement vector having a smaller contraction direction is generated in the right-hand region of the piezoelectric plate 102 than in the case where the phase is 135 °, but almost no displacement vector is generated in the left-hand region. Then, in the vicinity of the protrusion 102A, a displacement vector having a direction of about 315 ° smaller than that in the case where the phase is 135 ° is generated counterclockwise with respect to the positive direction of the X axis.

When the phase of the sine wave signal is 225 °, a displacement vector in the expansion direction is generated in the right-hand region of the piezoelectric plate 102, but almost no displacement vector is generated in the left-hand region. In the vicinity of the protrusion 102A, a displacement vector in the direction of about 135 ° is generated counterclockwise with respect to the positive X-axis direction.

When the phase of the sine wave signal is 270 °, a displacement vector in a larger expansion direction is generated in the right-hand region of the piezoelectric plate 102 than in the case where the phase is 225 °, but almost no displacement vector is generated in the left-hand region. In the vicinity of the protrusion 102A, a displacement vector in a direction of about 135 ° is generated counterclockwise with respect to the positive X-axis direction as compared with a phase of 225 °.

When the phase of the sine wave signal is 315 °, the phase vector is larger in the right hand region of the piezoelectric plate 102 than in the case of 270 ° and the maximum displacement vector in the expansion direction is generated, but almost no displacement vector is generated in the left hand region. In the vicinity of the protrusion 102A, a displacement vector having a maximum direction of about 135 ° is generated counterclockwise with respect to the positive X-axis direction as compared with the case where the phase is 225 °.

As described above, the piezoelectric plate 102 of the comparative example is deformed, but in the comparative example, a sine wave signal is applied to the individual electrode 103A in the right hand region of the piezoelectric plate 102, and the individual electrode 103B in the left hand region is in an open state. An AC voltage corresponding to a resonance frequency whose vibration mode is the E (3, 1) mode is applied between the individual electrode 103A and the common electrode 104 in the right hand region, so that E (3, 3 1) Asymmetric mode vibration is excited. At this time, since the individual electrode 103B in the left-hand region is in an open state, no inflow of charge from the ground to the individual electrode 103B in the left-hand region or no outflow of charge from the individual electrode 103B in the left-hand region to the ground occurs. 3,1) Mode symmetric mode vibrations are not excited. Therefore, the displacement vector of the protrusion 102A provided at the boundary between the left hand region and the right hand region maintains an inclination of 135 ° or 315 ° counterclockwise with respect to the positive direction of the X axis on the XY plane, The protrusion 102A is displaced so as to draw a linear reciprocating orbit. Therefore, in the comparative example, power is transmitted from the protrusion 102A to the linear slider 109 in the X-axis negative direction, and the linear slider 109 moves in the X-axis negative direction.

Next, a piezoelectric motor device 11 according to a second embodiment of the present invention will be described.

FIG. 5 is a circuit diagram of the piezoelectric motor device 11 according to the present embodiment.

In addition to the circuit configuration of the piezoelectric motor device 1 described above, the piezoelectric motor device 11 includes a switch 15A for switching an individual electrode connected to one side of the AC source 5 and an individual electrode connected to the other side of the AC source 5. A switch 15B for switching.

In this configuration, one side of the AC source 5 is connected to the individual electrode 3A, the other side is connected to the individual electrode 3B and the common electrode 4, and a connection point between the AC source 5, the individual electrode 3B, and the common electrode 4 Is connected to the ground, and one side of the AC source 5 is connected to the individual electrode 3B, the other side is connected to the individual electrode 3A and the common electrode 4, and is common to the AC source 5 and the individual electrode 3A. The switches 15A and 15B are controlled so as to switch between the state in which the connection point with the electrode 4 is connected to the ground.

One side of the AC source 5 is connected to the individual electrode 3A, the other side is connected to the individual electrode 3B and the common electrode 4, and the connection point of the AC source 5, the individual electrode 3B and the common electrode 4 is connected to the ground. In this state, the piezoelectric motor device 11 performs the same operation as the piezoelectric motor device 1 of the first embodiment.

On the other hand, one side of the AC source 5 is connected to the individual electrode 3B, the other side is connected to the individual electrode 3A and the common electrode 4, and the connection point of the AC source 5, the individual electrode 3A and the common electrode 4 is the ground. When the piezoelectric motor device 11 is connected to the piezoelectric motor device 11, the piezoelectric motor device 11 performs the reverse operation of the piezoelectric motor device 1 of the first embodiment, and the protrusion (not shown) is displaced in a counterclockwise circular or elliptical orbit. The linear slider (not shown) is moved in the negative direction of the X axis. Therefore, the piezoelectric motor device 11 of the present embodiment can switch the moving direction of the linear slider by the control of the switches 15A and 15B.

Next, a piezoelectric motor device 12 according to a third embodiment of the present invention will be described.

FIG. 6 is a circuit diagram of the piezoelectric motor device 12 according to the present embodiment.

The piezoelectric motor device 12 includes an AC source 5A in addition to the circuit configuration of the piezoelectric motor device 1 described above. That is, the piezoelectric motor device 12 has a two-phase power source. One side of the AC source 5 is connected to the individual electrode 3A, one side of the AC source 5A is connected to the individual electrode 3B, and the other side of the AC source 5 and the AC source 5A is connected to the common electrode 4. A connection point of the source 5, the AC source 5A, and the common electrode 4 is connected to the ground.

In this configuration, a sin (ωt) sine wave signal is applied from the AC source 5 to the individual electrode 3A, and a cos (ωt) sine wave signal is applied from the AC source 5A to the individual electrode 3B. 1) An AC voltage is applied between the

individual electrodes

3A, 3B and the common electrode 4 so that the phase difference between the symmetric mode and the asymmetric mode of the mode is 90 °. Similar to the piezoelectric motor device 1, the vibration of the elliptical motion in which the symmetric mode and the asymmetric mode of the E (3,1) mode are combined is excited. Therefore, the piezoelectric motor device 12 performs the same operation as the piezoelectric motor device 1 of the first embodiment.

In the piezoelectric motor device 1 of the first embodiment, since the individual electrode 3B is connected to the ground, only one AC source is required, but the phase difference between the symmetric mode and the asymmetric mode of the E (3,1) mode. Is about 90 ° only for certain frequencies. On the other hand, the piezoelectric motor device 12 of this embodiment has two AC sources, but the phase difference between the symmetric mode and the asymmetric mode of the E (3,1) mode may be about 90 ° at various frequencies. it can.

In the embodiment described above, an example in which a linear slider that linearly moves as a power transmission target has been shown, but a rotor that rotates in addition to the linear slider may be a power transmission target. In that case, by arranging the circumferential surface of the rotor so as to face the protrusion, the rotor can be rotated by a piezoelectric motor to obtain power of rotational motion.

The present invention is not limited to the description of the embodiment described above, and the scope of the present invention is indicated by the claims. The scope of the present invention includes not only what is indicated by the scope of claims but also all that are modified within the scope equivalent to the scope of claims.

DESCRIPTION OF

SYMBOLS

1, 11, 12 ... Piezoelectric motor apparatus 2 ... Piezoelectric plate 2A ...

Protrusion part

3A, 3B ... Individual electrode 4 ...

Common electrode

5, 5A ... AC source 6 ... Pressing spring 7 ... Frame 8 ... Bearing 9 ... Linear slider 15A, 15B …switch

Claims

A piezoelectric plate having a first surface including a first region and a second region adjacent to each other;
The first region is disposed on a boundary line between the first region and the second region, and is displaced in a first direction along the boundary line. The normal direction of the first surface of the piezoelectric plate and the first direction A power transmission unit that is displaced in a second direction perpendicular to the direction of 1;
Provided on a first individual electrode provided in the first region, a second individual electrode provided in the second region, and a second surface facing the first surface of the piezoelectric plate A drive unit that applies an AC voltage between the first individual electrode and the common electrode, and prevents the second individual electrode from becoming a floating electrode;
A piezoelectric motor comprising:
The drive unit has one side connected to the first individual electrode, the other side connected to the second individual electrode and the common electrode, and the first individual electrode and the common electrode. Including an AC source for applying an AC voltage between them,
2. The piezoelectric motor according to claim 1, wherein the second individual electrode, the common electrode, and the other side of the AC source are connected to a ground.
3. The piezoelectric device according to claim 2, wherein the driving unit applies an AC voltage corresponding to a resonance frequency whose vibration mode is an E (3,1) mode between the first individual electrode and the common electrode. motor.
The drive unit simultaneously excites E (3,1) mode symmetric mode vibration and asymmetric mode vibration over the entire piezoelectric plate, and the phase difference between the E (3,1) mode symmetric mode and the asymmetric mode. 4. The piezoelectric motor according to claim 3, wherein an AC voltage is applied between the first individual electrode and the common electrode so that the angle is about 90 °.
The drive unit includes an AC source that applies an AC voltage between the first individual electrode or the second individual electrode and the common electrode,
One side of the AC source is connected to the first individual electrode, the other side is connected to the second individual electrode and the common electrode, and the second individual electrode, the common electrode, and the AC The other side of the source is connected to ground,
One side of the AC source is connected to the second individual electrode, the other side is connected to the first individual electrode and the common electrode, and the first individual electrode, the common electrode, and the AC The other side of the source is connected to ground,
The piezoelectric motor according to claim 1, further comprising a switch for switching between the two.
The drive unit applies an AC voltage corresponding to a resonance frequency in which a vibration mode is an E (3,1) mode between the first individual electrode or the second individual electrode and the common electrode. The piezoelectric motor according to claim 5.
The drive unit simultaneously excites E (3,1) mode symmetric mode vibration and asymmetric mode vibration over the entire piezoelectric plate, and the phase difference between the E (3,1) mode symmetric mode and the asymmetric mode. The piezoelectric motor according to claim 6, wherein an AC voltage is applied between the first individual electrode or the second individual electrode and the common electrode so that the angle is about 90 °.
The drive unit has one side connected to the first individual electrode and the other side connected to the common electrode, and applies an AC voltage between the first individual electrode and the common electrode. 1 AC source, one side is connected to the second individual electrode, the other side is connected to the common electrode, and an AC voltage is applied between the second individual electrode and the common electrode A second AC source,
The piezoelectric motor according to claim 1, wherein the other side of the first AC source and the other side of the second AC source are connected to a ground.
The drive unit has a resonance frequency in which a vibration mode is an E (3,1) mode between the first individual electrode and the common electrode, and between the second individual electrode and the common electrode. The piezoelectric motor according to claim 8, wherein an AC voltage corresponding to is applied.
The drive unit simultaneously excites E (3,1) mode symmetric mode vibration and asymmetric mode vibration over the entire piezoelectric plate, and the phase difference between the E (3,1) mode symmetric mode and the asymmetric mode. The AC voltage is applied between the first individual electrode and the common electrode, and between the second individual electrode and the common electrode, so that is about 90 °. Piezoelectric motor.
A piezoelectric motor according to any one of claims 1 to 10,
A power converter disposed on the first direction side of the piezoelectric plate;
A piezoelectric motor device comprising:
12. The piezoelectric motor device according to claim 11, wherein the power conversion unit is a linear slider that is movable with the second direction as a moving direction.