JPS6135176A - Piezoelectric motor - Google Patents

Abstract

PURPOSE:To obtain a piezoelectric motor which rotates at a high speed efficiently for obtaining a drive force by vibrating a piezoelectric unit by increasing the vibrating displacement generated to the unit specific times of the drive surface roughness. CONSTITUTION:A piezoelectric motor in which a vibration generated at a piezoelectric unit is transmitted to a stator (drive unit) to generate a drive force at a slider contacted with the stator, the vibration displacement generated at the unit is increased by 1.5 times or more of the surface roughness of the stator. Thus, since the magnitude of the amplitude increases larger than the surface roughness of the dynamic surface state time of the stator and the slider, they are contacted only near the crests of the amplitude to readly produce a peak speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a motor that generates driving force using a piezoelectric material.

(Conventional structure and its problems) In recent years, piezoelectric motors that obtain rotational or running motion by exciting various ultrasonic vibrations using electromechanical transducers such as piezoelectric ceramics have a high energy density. It is attracting attention because of this.

A conventional piezoelectric motor using these ultrasonic vibrations will be described below with reference to the drawings.

Figure 1 shows an example of a conventional piezoelectric motor published in Nikkei Mechanical (57, 2, 28).
A piezoelectric element ring 2 is bonded and integrated on the 0 surface, and this is used as a stator. The piezoelectric element ring 2 has a center angle of 22.5° in the circumferential direction, for example, as shown in FIG.
Or 11. , and is divided into 17 regions with a division ratio of 25°, and electrodes are attached and polarized. The direction of polarization is opposite in adjacent regions. Thereafter, the surface of the piezoelectric element is covered with conductive paint and the electrodes are combined into two parts as shown by diagonal lines. E
is the ground terminal. A moving body 4 to which a slider 3 is fixed is located above the elastic ring 1. The conventional piezoelectric motor having the above configuration utilizes Rayleigh waves, which are also called surface acoustic waves. This wave is a wave that propagates near the surface of a material, and the wave has both longitudinal and transverse wave components.

In addition to the conventional piezoelectric motor configured as described above, two-phase and three-phase
Using the same principle as a phase motor, when an AC signal with a shifted phase is applied, the piezoelectric body expands and contracts in the circumferential direction, and a surface wave is generated in the stator. Figure 3 is an enlarged depiction of the contact situation between the stator of a conventional piezoelectric motor and a moving object that comes into contact with its surface.
For example, see Nobuo Mikoshiba's "Sonic Physics", published by Sanseidosha in 1972), if we focus on one point A on the surface of an elastic body, point A traces a locus on an ellipse with a major axis of 2 W % and a minor axis of 2 uO. There is. At the vertex where the elastic body makes contact with the moving body, point A is
It has a velocity of v-2πfu in the negative direction of the axis.

As a result, the moving body is driven by the frictional force with the elastic body in the direction opposite to the direction of wave propagation at a speed of ■. By drawing an elliptical locus as a thrust on the surface of the elastic body in this way, the conventional piezoelectric motor guides the rotation of the moving body (rotor) in contact with the piezoelectric motor.

The amplitude of this elliptical trajectory in the long axis W direction is at most 0.5 μm
The amplitude in the minor axis +1 direction is at most 0.25
It is on the order of μm. In addition, this piezoelectric motor using surface waves uses the same principle as a two-phase or three-phase motor, and the direction of rotation can be easily switched using a phase-shifted power supply.

However, the above configuration has the following problems.

(1) The stress required to obtain the vibration mode that is the driving principle is:
The maximum value is shown on the stator surface. In a stator with a thickness of 3Wn, the normal stress is about 2000 kg/m2, and the electric power required to resist this is about 100 to 1000 degrees, which is the normal theoretical value of Guimorph.

(2) Since the neutral surface of vibration is still inside the elastic body such as the metal that constitutes the stator, the piezoelectric material used as an electro-mechanical transducer does not provide efficient nodal drive, Drive and force9. Even if it is limited to the piezoelectric material that is the drive source,
In this driving principle, more than 5/8 of the total energy is reactive energy.

(3) In addition, in order to extract thrust from a minute amplitude of approximately 0.25 μm or less, the moving object uniformly contacts the peaks and troughs of the stator, which have different amplitudes at different speeds and directions. The speed is lower than the integral value.

Therefore, in order to obtain practical rotation speed and torque,
It requires about 10 to 100 times more power than conventional motors.

(4) In addition, in conventional piezoelectric motors with surface waveforms, the drive electrodes are separated into two sets), so either the wave excited by the A electrode is propagated to the B electrode side, or conversely, the wave excited by the B electrode is propagated to the A electrode side. It is propagated as a wave with a longitudinal wave component and a transverse wave component on the electrode side,
Generates an elliptical trajectory on the surface of an elastic body. Due to this driving principle, the stator has to have an endless configuration, which is a configuration that uses the second-order effect after exciting the -order amplitude and has an extremely narrow range of application. There is. That is, it has many of the problems mentioned above, such as the impossibility of using the direct and powerful thrust of a disk or rectangular plate due to space waves or bulk waves.

(Objective of the Invention) The object of the present invention is to solve the above-mentioned various drawbacks: 1.
Focusing on the highly efficient space waves or bulk waves excited by piezoelectric ceramic vibrators, we have achieved extremely efficient practical use by using these as direct driving force and by increasing the vibration displacement using vibration transmission members, etc. The purpose of this invention is to provide a piezoelectric motor with a unique design.

(Structure of the Invention) A piezoelectric motor according to the present invention includes a stator in which two piezoelectric vibrators and an acoustic material are stacked in the thickness direction;
The slider is provided with a slider that is overlapped with the stator in the thickness direction and makes surface contact with the stator, and has a vibration transmission member on the surface of the stator. Both piezoelectric vibrators have thickness direction polarization consisting of one or more pairs of divided regions divided in the slider movement direction, and the directions of these polarizations are opposite to each other in adjacent regions. Both piezoelectric vibrators are arranged so that the boundary of each polarized region on one side is located near the center of each polarized region on the other side. When the piezoelectric vibrators configured as described above are driven with voltages of predetermined forced excitation frequencies that are out of phase with each other, the combined vibration of the stator caused by both piezoelectric vibrators is expanded in the vibration transmission member. In addition, the maximum amplitude position moves in a certain direction over time, and the slider in contact with the apex receives a driving force in that direction.

(Explanation of Examples) Details of embodiments of the present invention will be described with reference to the drawings.

The stator has a structure as shown in FIG. 4, for example. For example, the surface of the disk-shaped first piezoelectric vibrator 5 has a central angle of 45°.
Eight electrodes 5a are provided divided into different regions. This electrode 5a is made of silver.

It is formed on the surface of the first piezoelectric vibrator 5 by a method such as printing, vapor deposition, or plating using a conductive material such as silver palladium, rhodium, or nickel. The electrode (not shown) provided on the back surface may or may not be divided like the front electrode. Polarization is performed so that the polarization directions of adjacent electrodes of the first piezoelectric vibrator 5 configured as described above are different from each other in the thickness direction. As a result, as shown in FIG. 4, four sets of forced excitation vibrators with eight poles each consisting of regions having alternately positive or negative polarities are constructed. After polarization, the electrodes 5a do not need to be divided and are connected so that a voltage can be applied all at once. The disk-shaped second piezoelectric vibrator 6 also
It has the same structure as the piezoelectric vibrator 5, and includes four sets of forced excitation vibrators with eight poles having alternating glass polarity or negative polarity.

The minimum amplitude position of the first piezoelectric vibrator 5 or the second piezoelectric vibrator 6 is near the boundary between adjacent electrodes, and the maximum amplitude position is near the center of each electrode. Both piezoelectric vibrators 5°6 have a second piezoelectric vibrator 6 located near the center of the electrode, which is the maximum amplitude position of the first piezoelectric vibrator 5.
The electrodes are superimposed so that the boundary between adjacent electrodes is located at the minimum amplitude position.

The first piezoelectric vibrator 5 and the second piezoelectric vibrator 6 configured as described above are mounted on a stator base 7 having a thickness equal to or about ten times as thick as the piezoelectric vibrator. The stator base 7 is made of an acoustic material or a friction material made of aluminum, brass, iron, stainless steel, hardened steel, synthetic resin material such as nylon, ceramic material, glass material, or a composite material made of these materials. It is formed using Still on the surface of the stator base 7,
For example, a protrusion 8, which is a vibration transmitting member, is formed near a position that is approximately the same as the diameter, and a shaft 9 is formed at the center.

The structure constructed as described above is used as the stator 10 shown in FIG. As shown in FIG. 5, the output signal oscillated by the oscillator 11 at the forced excitation drive frequency determined by the stator 10 is branched, and one side is directly sent to the amplifier 12.
The other signal is input to the amplifier 14 via the phase shifter 13. The phase shifter 13 shapes a signal whose phase is shifted within a range of ±10' to ±170°, which is used for forward rotation or reverse rotation as will be described later. The output signal of the oscillator 11 is directly input to the amplifier 12 and the amplified signal is applied to the first piezoelectric vibrator 5 through lead wires 15 and 16. Therefore, the solid electron 10 has 8 poles, each having 4 wavelengths corresponding to 4 sets of forced excitation oscillators, with each wavelength being a pair of regions in which the polarization directions of the first piezoelectric oscillator 50 have mutually different positive polarity or negative polarity. A forced excitation wave is generated. The second piezoelectric vibrator 6 is similarly driven by applying the output of the amplifier 14 via the lead wires 16 and 17.

FIG. 6 shows the change in longitudinal strain with respect to the circumferential position at a position of approximately 70% of the maximum diameter when an electric signal is applied to the first piezoelectric vibrator 5 and the second piezoelectric vibrator 6. The results are shown below. The measurement was performed by irradiating the measurement location with a He-Ne gas laser beam and using an interference method between incident light and reflected light. FIG. 6(,) shows the measurement results when the first piezoelectric vibrator 5 was driven by applying signals to the lead wires 15 and 16. When 50V was applied, the amplitude was approximately ±0.8 μm. The minimum amplitude position is near the boundary between adjacent electrodes, and the maximum amplitude position is near the center of each electrode. FIG. 6(b) shows the results of longitudinal strain measured when the second piezoelectric vibrator 6 was driven in the same manner. When 50V was applied, the amplitude was about ±0.8 μm. The minimum amplitude position is near the boundary between adjacent electrodes, and the maximum amplitude position is near the center of each electrode.

Next, FIG. 6(c) shows the measurement results when the first piezoelectric vibrator 5 and the second piezoelectric vibrator 6 were simultaneously driven in the configuration shown in FIGS. 4 and 5. In the distribution of strain in the vertical direction, the position where the amplitude is maximum has moved to an intermediate position between FIGS. 6(a) and 6(b). Furthermore, the maximum amplitude of the vertical type is approximately 1.3 times larger. Here, as described above, the second piezoelectric vibrator 6 is +1 with respect to the first piezoelectric vibrator.
Since it is driven with a phase shift of 0° to ±170°,
The maximum amplitude position of the composite wave in FIG. 6(C) moves in a constant direction with time.

A slider 18 is in contact with the top of the stator 10. The slider 18 is composed of an acoustic material 20 coupled to the left side of an elastic body 19 made of a friction material, an elastic material, or the like.

When the stator 10 is driven as described above, the apex of the vibration on the side of the stator 10 facing the slider 18 comes into contact with the slider 18, and the apex moves with time.
A force having a lateral component is applied to the slider 18. In this way, the slider 18 repeatedly moves in position due to the lateral component according to the drive frequency determined by the stator 10, and as a result, the slider 18 obtains rotational motion in the range of approximately several to several thousand revolutions per minute. I can do it. The generated torque varies depending on the acoustic materials that make up the stator, the friction coefficient and contact area of the slider that makes surface contact with the stator, the magnitude of the load, etc., but it ranges from several tens of gf-m to several thousand gf-m. gi
It was possible to obtain torque in the cn range. Also, regarding the direction of rotation, +10° to +17° relative to the reference signal.
If the rotation obtained when driving the second piezoelectric vibrator by applying a signal with a phase shift in the range of 0° is, for example, positive rotation, then the phase shift will be in the range of 110° to 1170° with respect to the reference signal. The direction of rotation obtained when driving by simultaneously applying these signals is rotation in the opposite direction. Further, the rotation speed can be arbitrarily selected by selecting the magnitude or phase of the applied signal, or the magnitude of the load received by the contact portion.

Furthermore, according to the configuration shown in FIGS. 4 and 5, the heavy load of distorting metal with a large Young's modulus in the conventional system is eliminated. In the conventional method, it is considered possible to increase the short axis 2u of the elliptical locus by further increasing the thickness of the gold to be bonded. The size of the dynamic range of the resonance characteristics indicates the level of strong excitation, and for each increase in the metal thickness by 1μ, the resonance characteristics increase by 15
Since the attenuation is about dB, driving with large electric power is required to actually increase the short axis 2u which becomes the thrust. In this case, since the structure has extremely poor linearity, a high amount of heat is generated, but the increase in thrust is extremely small.

FIG. 79 shows the distortion in the vertical direction of the stator 10 according to the present invention when an electric signal is applied to the stator 10, and the distortion in the vertical direction is shown by a virtual line.
The results are shown as the change in the cross-sectional direction of .

The measurement was carried out using the interferometry method using laser light, similar to the measurement in the circumferential direction. When 5'OV was applied, a maximum amplitude of about 1.8 μm was exhibited near the protrusion 8, which is the vibration transmission member shown in FIG. The phase shift turning point of the amplitude, the so-called vibration node, changes almost linearly from 80 to 85 inches, assuming the diameter is 100%, and the end is 2.5 μm.
The amplitude was about the same level. Furthermore, when the lead wires 15, 16, and 17 for applying electrical signals were taken out near the vibration nodes, there was no disconnection due to vibration fatigue. In addition, as shown in FIG. 13 described later, as a practical structure, the stator 1
A buffer body 35 is provided at the bottom of o. In that case, the stator 1o is curved as shown in FIG. 7 using the buffer body 35 as a base, so that the apparent root width is expanded.

Furthermore, if the support position is located near the vibration node, a drive with less loss can be realized. As a result, the lateral component that becomes the thrust of the slider 18 increases in the protrusion 8, and the slider 1
8 moves in a certain direction extremely efficiently.

FIG. 8 shows the relationship between the driving voltage and the rotation speed of the piezoelectric motor according to the present invention. For comparison, characteristics of a conventional surface waveform piezoelectric motor are shown in a. b is the characteristic of the piezoelectric motor according to the present invention without the protrusions, C is the characteristic when the vertical length of the protrusion of the piezoelectric motor according to the present invention is 4 sieves, and d is the protrusion of the piezoelectric motor according to the present invention. The characteristics are shown when the length in the downward direction is 8 times. By changing the vertical length of the protrusion 8 of the stator in this manner, the desired running speed could be obtained. From these facts, it can be seen that the piezoelectric motor according to the present invention is extremely efficient. In FIG. 8, the maximum speed is 36 rpm, but in a prototype machine with a larger diameter or a model with a smaller diameter of the protrusion 8, a speed of about 11,000 rpm could be measured.

Moreover, the power consumption at this time was about 1/10 to 1/100 of that of a conventional piezoelectric motor. Furthermore, the power efficiency and DC micro motors have relatively good values.On the other hand, the rotation speed of conventional piezoelectric motors ranges from a few revolutions to 30 r.
It is limited to about pm. This is based on the drive principle of a surface waveform using a minute amplitude of submicron. Conventional piezoelectric motors are characterized by low speed and are intended for driving camera lenses and the like.

In the piezoelectric motor according to the present invention, which directly uses spatial waves or bulk waves that produce strong vibrations, when the protrusion 8 is at a height of, for example, 8 brightness, as shown in FIG. 4, the apparent amplitude is The stator and slider come into contact only at the peak of the vibration amplitude, which is about 4 μm, so at a driving voltage of 50 V, the speed is 220 rpm.
It is getting a certain number of rotations. FIG. 9 shows the relationship between the diameter and the number of rotations when the diameter of the protrusion 8 is changed. As is clear from FIG. 9, the piezoelectric motor according to the present invention has 1
The desired rotation speed can be obtained by selecting the diameter or height of the protrusion 8, ranging from several rotations per minute to about 1,000 rotations per minute. Furthermore, since the characteristics are linear up to a drive voltage of about 200V, the number of rotations can be increased by increasing the voltage. In addition, since the construction principle or component parts do not have any magnetic means such as magnets or coils, for example, 400 rpm or 700 rpm.
A piezoelectric motor of about 100 m in diameter can be ideally used as a motor for magnetic recording/reproducing equipment such as floppy disks or video Teso recorders, as it has no magnetic influence.

FIG. 10 shows a stator with another configuration.

In this configuration, the basic configuration is that a stator base 23 having a thickness equal to or about 10 times that of the piezoelectric vibrators is mounted between the first piezoelectric vibrators 21 and 21' and the second piezoelectric vibrator 22. There is.

Further, on the surface of the stator base body 23, a protrusion 24 is formed near a position where the diameter is approximately A consistency, and a shaft 25 is formed at the center. The materials and structures of each member are the same as those in the embodiment shown in FIG. The relative polarization arrangement of the first piezoelectric vibrator 21° 21' and the second piezoelectric vibrator 22 is exactly the same as that of the stator 1o having the structure shown in FIGS. 4 and 5. First piezoelectric vibrator 2'l
, 21' is divided into two pieces and has a small hole in order to allow the protrusion 24 and shaft 25 to pass through. Further, as the drive circuit for this stator, the same structure as the circuit shown in FIG. 5 can be used, so a detailed explanation will be omitted.

FIG. 11 shows a stator in yet another embodiment. In this embodiment, the first piezoelectric vibrator electrode 26 and the second
The basic configuration includes a piezoelectric vibrator 28 having a piezoelectric vibrator electrode 27 and a stator base body 29 having a thickness equal to or about 10 times that of the piezoelectric vibrator. Furthermore, a ring-shaped projection (not shown) and a shaft 30 are formed on the surface of the stator base body 29 in the vicinity of a position that is about the same diameter. The materials and structures of each member are the same as those in the embodiment shown in FIG. The relative polarization arrangement of the first piezoelectric vibrator electrode 26, the second piezoelectric vibrator electrode 27, etc. is exactly the same as that of the stator 10 having the configuration shown in FIGS. 4 and 5. Further, as the drive circuit for this stator, the same structure as the circuit shown in FIG. 5 can be used, so a detailed explanation will be omitted.

FIG. 12 shows a stator in yet another embodiment. In this embodiment, an annular stator base 33 having a thickness equal to or about 10 times that of the piezoelectric vibrator is provided on top of a first annular piezoelectric vibrator 31 and a second annular piezoelectric vibrator 32. The basic configuration is that it is installed. Further, a protrusion 34 is formed near the maximum vertical amplitude on the surface of the stator base 33.
is formed. The materials and structures of each member are the same as those in the embodiment shown in FIG. The relative arrangement of the polarizations of the first piezoelectric vibrator 31 and the second piezoelectric vibrator 320 is exactly the same as that of the stator 10 having the configuration shown in FIGS. 4 and 5. As the drive circuit for this stator, the same structure as the circuit shown in FIG. 5 can be used, so a detailed explanation will be omitted.

Using the drive circuit shown in Fig. 5, the stators shown in Figs.
When the strain in the vertical direction was measured when V was applied, the results obtained were exactly the same as those shown in FIGS. 6 and 7. When these stators were installed and driven in a structure similar to that of the piezoelectric motor according to the present invention shown in FIG. We were able to obtain rotational motion. The generated torque varies depending on the acoustic material forming the stator, the friction coefficient and contact area of the slider etc. that makes surface contact with the stator, etc., or the magnitude of the load received.
It is possible to obtain torque ranging from several tens of gf-α to several thousand gf-α.

FIG. 13 shows a more specific structure of a piezoelectric motor in an embodiment of the present invention. The same parts as in FIG. 5 are given the same numbers. The stator 10 provided with lead wires 15, 16, and 17 is attached to a frame (not shown) via a buffer 35 so as to be able to vibrate freely. A slider 18 is in contact with the top of the stator 10 via a bearing 36 inserted into the shaft 9. The pressing force adjustment screw 37 is attached to the upper end of the shaft 9, and when it is tightened, the picture leaf spring 38 is bent, and the stator 10 and the slider 18 can be brought into contact with each other with an arbitrary pressing force. . As a result, tens of gf-α to several thousand gi
It is possible to obtain torque in the range of z. Also, slider 18
A fixing ring 39 is fixed on top of the rotating body, and rotation is transmitted to the rotating body by sandwiching the rotating body between the fixing ring 39 and a guide ring 40 shown in phantom lines.

FIG. 14 shows an enlarged view of the state of contact between the stator and the slider (rotor) of the piezoelectric motor of the present invention constructed as described above and the conventional piezoelectric motor during actual driving. 1st
FIG. 4(a) shows the contact situation of a conventional piezoelectric motor for one wavelength in the circumferential direction.

With a minute amplitude of about 0.5 μm, even during actual driving, the peaks and valleys of the amplitude are a dynamic surface condition that appears during rotation or running, and the roughness of the stator surface is approximately 1 μm.
Alternatively, the roughness of the slider contacting surface is small, such as about 10 μm, so that thrust cannot be effectively applied to the slider. FIG. 14(b) shows the state of contact between the stator and the slider (rotor) in one wavelength in the circumferential direction of the piezoelectric motor according to the present invention. When the amplitude becomes about 2 μm, the magnitude of the amplitude becomes larger than the above value when the stator/slider (rotor) is in a dynamic surface state, so the amplitude of the stator (stake) becomes larger. The slider (rotor) comes into contact near the peak of
There are no contact points near the amplitude valley where the force acting on the slider (rotor) is in the opposite direction. Furthermore, in the radial distribution of the stator, in the conventional method, the stator and slider (rotor) remain in uniform contact even during actual driving, but the piezoelectric motor according to the present invention The stator and slider (rotor) contact each other only in the vicinity of the peak of the amplitude during actual driving even in the longitudinal direction, and the generated speed differs in the width direction of the stator (stator). The peak speed on the child (stator) can be easily output. Due to this, for a constant input,
Compared to conventional piezoelectric motors, we were able to achieve speeds several dozen times higher.

FIG. 15 shows surface roughness, stator displacement, and running speed characteristics. In a piezoelectric motor, the space between the stator and slider (rotor) rotates and wears out.
The surface roughness of the contact surface is approximately 1 on the stator side.
On the slider (rotor) side, which uses a material with a large coefficient of friction (μm), the friction coefficient is approximately 10 p, m, and the vibration transmission member 8 described in Figs. value is kept.

The magnitude of the stator displacement at this time is within 1.5 to 2.5 times the surface roughness (for example, about 1 μm) (
If the amplitude value is within about 0.75 to 1.25 μm), the slider (
The rotor) uniformly contacts the peaks and troughs of different amplitudes in the speed and direction of the generated speed in the stator (stator), and the speed of the slider (rotor) in contact is the integral value. The difference is that the speed is lower. If the displacement of the stator is about 1.5 to 2.5 times or more than the surface roughness (for example, about 1 μm), the stator
Since the magnitude of the amplitude is larger than the above value in the dynamic surface condition of the slider (rotor), etc., the two contact each other only near the peak of the amplitude, and the peak speed can be easily output. It is something.

The piezoelectric motor with the above configuration has a small apparent storage area, and can be driven in forward or reverse directions at will by simply changing the phase of the drive signal.
Thousands of gf-ffl at low and medium speeds within rpm
Torque within a certain range can be generated. However, the rotation speed can be arbitrarily selected up to about several thousand rotations by selecting the magnitude or phase of the applied signal, the magnitude of the load received by the contact portion, the length and diameter of the protrusion, etc. Therefore, there is no need for a speed reducer or the like. Moreover, since it always forms a contact friction pair, there is no moment of inertia, and it is rich in minute pulse operation and has excellent contact properties. Furthermore, since the structure is extremely simple, the price is low.

(Effects of the Invention) As described above, the piezoelectric motor according to the present invention includes two piezoelectric vibrators in the stator, and both piezoelectric vibrators have at least polarization directions reversed alternately in the slider movement direction. The piezoelectric vibrator is divided into a pair of regions, which are arranged approximately half a region apart from each other, and a slider is brought into contact with the stator via a vibration transmission member. By applying a voltage with a predetermined frequency that is shifted from the above, a vibration wave moving in a fixed direction is generated in the stator, and the effect of expanding the displacement in the vibration transmission member increases the efficiency of the slider. It is well driven. Therefore, the motor can be configured with an extremely simple structure, and a small and responsive motor can be realized. Moreover,
1 in a structure in which a disk-shaped bulk wave is directly excited by the left means.
The structure is such that the lateral component that becomes the thrust is obtained, so the mechanical displacement is several times greater at a constant voltage, and the entire deflection in the cross-sectional direction is output, so the speed is averaged. It is possible to achieve peak speed without

[Brief explanation of the drawing]

1 and 2 are a sectional view and a plan view showing the configuration of a conventional piezoelectric motor, respectively, FIG. 3 is a perspective view showing its operation, and FIG. 4 is a piezoelectric motor according to an embodiment of the present invention. FIG. 5 is an exploded perspective view of the stator. FIG. 5 is a diagram showing a cross section of a piezoelectric motor using the same stator and its drive circuit. FIGS. 6 and 7 are diagrams showing the piezoelectric motor stator shown in FIG. FIG. 8 is a graph showing the characteristics of the rotation speed versus drive voltage of the piezoelectric motor according to the present invention, and FIG. 9 is a graph showing the rotation speed versus the diameter of the main part of the stator of the piezoelectric motor according to the present invention. 10, 11, and 12 are exploded perspective views of a stator of a piezoelectric motor according to another embodiment of the present invention, and FIG. 13 is a diagram showing characteristics of a piezoelectric motor according to an embodiment of the present invention. FIG. 14 is a cross-sectional view showing the specific structure of the motor, FIG. 14 is a diagram showing the contact states of a conventional piezoelectric motor and a piezoelectric motor according to the present invention, and FIG. 15 is a diagram showing surface roughness and stator displacement of the piezoelectric motor. FIG. 3 is a diagram showing the traveling speed characteristics. 5.6, 21.21', 22.28, 31, 32...
Piezoelectric vibrator, 51L r 26 + 27... electrode,
10... Stator, 18... Slider, 11... Oscillator, 12° 14... Amplifier, 13... Phase shifter. B Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13

Claims (1)

[Claims] A piezoelectric motor that generates driving force using a piezoelectric material or the like, characterized in that the vibrational displacement generated by the piezoelectric material or the like is about 1.5 times or more the surface roughness of the drive body made of the piezoelectric material or the like. piezoelectric motor.