JPS62239875A - Drive control method for ultrasonic vibrator - Google Patents

Abstract

PURPOSE:To increase an efficiency of vibration at the maximum torque by applying a driving power so that an output end face of diaphragm performs a composite vibration synthesized in its axial and flexible directions. CONSTITUTION:Vertically polarized electrostriction element plates 2-3 are made to adhere to both faces of a longitudinally central part of rectangular diaphragm 1 and cable terminals 6-8 are taken out from respective electrodes 4-5 and so on to constitute an ultrasonic vibrator. Also, the diaphragm 1 is formed in the manner of making its longitudinal and flexiblie resonance frequencies correspond with each other. In this vibrator, moreover, the cable terminals 6-7 are connected in parallel so that an AC power is applied between said terminals and the common cable terminal 8 to make the vibrator perform a resonance vibration in axial and flexible directions. In this manner, various composite vibration modes can be created by a rectangular synthesis of sine- wave vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the drive of an ultrasonic vibrator that is useful when applied to an ultrasonic motor.

[Conventional technology]

Conventionally, a vertical vibrator that resonantly vibrates in the axial direction is integrated with a conversion member that converts the axial vibration into the torsional direction, and the resulting elliptical vibration of the output end causes a vibration between the rotor and other rotating bodies or moving bodies. Ultrasonic motors driven by frictional contact are known.

An example of this is a rotary drive device using ultrasonic vibrations, which is described in Japanese Patent Publication No. 59-37672. This rotary drive device has a diaphragm provided on one end surface of one or more ultrasonic transducers and one end surface of a rotating shaft facing each other in a casing main body, and a diaphragm provided on one end surface of one or more ultrasonic transducers and one end surface of a rotating shaft are arranged facing each other, and the diaphragm is disposed between the two in the axial direction of the rotating shaft. The ultrasonic transducer is characterized by converting the reciprocating motion of the ultrasonic transducer into rotational motion of the rotating shaft by integrally forming a vibrating piece having an inclination angle with either the rotating shaft or the diaphragm. When a vibrating piece is installed at the output end of an axial vibrator and pressure is applied with the normal line of the joint surface of a movable member such as a rotor slightly inclined to the axis of the vibrator, the tip of the vibrating piece generates elliptical vibration. The movable members such as the rotor are driven by friction.

There is also an ultrasonic motor as shown in FIG. This ultrasonic motor integrates a vertical vibrator 60 and a torsion transducer 63, which has a wide groove 61 on one surface and a beam-shaped protrusion 62 at a certain angle with the groove 61 on the other surface. The rotor 66 is pressed against the beam-like projection 62 by a bolt 64 that is tightened and screwed into a female thread provided at the center of the beam-like projection 62 and a coil spring 65, and longitudinal vibration is applied to the torsion converter 63. Then, the converter 63 generates bending vibration, and the beam-like protrusion 62 tilts in the opposite direction at both ends according to the bending angle, generating elliptical vibration in the direction of the arrow in the figure. 67, it rotates clockwise.

In contrast to the above-described method in which the vibration direction of a unidirectional vibrator is converted into a complex vibration by a converter, the present applicant proposed a method in which the axial direction and torsional direction vibrations are individually driven to generate a complex vibration. Japanese Unexamined Patent Application Publication No. 1986, filed by
There is a method disclosed in Japanese Patent No.-28482. That is, the present invention provides a system for integrally fastening a radial or longitudinal resonator located at a node portion of a torsional vibrator and having its resonance frequency set to be the same as the torsional resonance frequency at right angles to the axis, and its driving element. In such a vibrator, the state of the composite vibration at the output end is controlled by changing the amplitude or relative phase, or the amplitude and relative phase of each vibrator, and such a vibrator constitutes, for example, an ultrasonic motor. , JP-A-61, which was also filed by the present applicant.
There is one disclosed in Japanese Patent No. -30972.

[Problem that the invention seeks to solve]

However, in the vibrating piece type described above and the vertical torsion conversion type shown in FIG. Therefore, it is impossible to control the ellipticity to the optimum ellipticity for frictional drive or to control the direction of rotation. In other words, both drive the rotor in a single direction,
Furthermore.

It is not possible to control the elliptical shape required to reduce contact surface wear and efficiently drive at maximum torque.

Furthermore, the above-mentioned JP-A-61-28482 and JP-A-6
In the device disclosed in Publication No. 1-30972, since the torsional and axial directions can be driven separately, various complex vibrations can be obtained by controlling the amplitude and relative phase of each. In contrast, the components of the resonator in the radial or longitudinal direction are larger, resulting in a larger vibrator or motor.

[Means for solving problems]

The present invention has been made with the aim of solving the problems of the prior art as described above, and is configured to provide an ultrasonic vibrator in which electrostrictive element plates are attached to both sides of a diaphragm. In order to make the output end face of the diaphragm generate a composite vibration in the axial and flexural directions, a flexural drive power source with a reverse phase is applied to each pair of electrodes, and an axial drive power source is superimposed on each electrode. The main feature is that the amplitude or relative phase of each, or the amplitude and relative phase of each are controlled by the above.

[For production]

By means of the above means, it is possible to generate torsional or perpendicular vibration to the axis, and linear vibration, circular vibration, and elliptical vibration, which are a combination of axial vibration, in any direction on the output end face of the diaphragm.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

What is shown in FIG. 1 is electrostrictive element plates 2 and 3 which are polarized in the thickness direction and provided with electrodes on both sides of the central part in the length direction of a rectangular diaphragm 1 made of an elastic body such as metal. are bonded with conductive adhesive or the like, and the electrostrictive element plate 2
Lead terminals 6 and 7 connected by soldering etc. are pulled out from one electrode 4 of the electrostrictive element plate 3 and one electrode 5 of the electrostrictive element plate 3, and the other electrode of each electrostrictive element plate 2 and 3 is connected to the diaphragm 1. It is electrically connected to and taken out as a common lead terminal 8.

The ultrasonic vibrator configured as described above connects its lead terminals 6 and 7 in parallel, applies an AC voltage between it and the common lead terminal 8, and sets the frequency to resonance in the longitudinal direction of the diaphragm 1. As is well known, when adjusting the frequency,
Both end surfaces 9 and 10 of the diaphragm 1 resonate in the axial direction with maximum displacement as indicated by arrow A.

On the other hand, the AC f! applied to lead terminals 6 and 7! If the phase difference in Note is 180 degrees, that is, the phase is inverted, and the frequency is matched to the flexural resonance frequency, the end faces 9 and 1 of the diaphragm 1
0 vibrates linearly in the direction of deflection, that is, in the direction perpendicular to the axis, as shown by arrow B in FIG.

Here, the diaphragm 1 including the electrostrictive element plates 2 and 3 is formed so that its longitudinal resonant frequency and flexural resonant frequency match.

FIG. 2 shows a wiring diagram when driving the above ultrasonic transducer. The common lead terminal 8 of the vibrator is connected to the ground side end of the drive power source 11 and grounded.

The lead terminals 6 and 7 are connected to both ends 13 and 14 of the secondary coil of the transformer 12, respectively, the center tap 15 is connected to the drive power supply 11, and the secondary coil 16 is connected to the drive power supply 17, and one end is grounded. Ru.

Therefore, when the drive power supplies 11 and 17 are driven in the same phase at a resonant frequency, the vibration at point C of the output end 9 will be such that the axial vibration 20 and the flexural vibration 21 are at right angles to each other, as shown in FIG. Therefore, the resultant vibration becomes a straight line 22, and if the relative phase is reversed and the axial vibration is shown as a dotted line 23, the resultant vibration becomes a dotted line 24, and the vibration direction changes by 90 degrees.

Also, if the relative phase is 90 degrees, the resultant vibration is circular vibration 25
The direction of rotation is reversed depending on whether the phase is advanced or delayed. Furthermore, by changing the relative amplitude, it becomes an elliptical vibration, and by combining the relative amplitude and relative phase, it becomes an inclined ellipse, etc. By orthogonally synthesizing the sinusoidal vibration,
As is well known in the past, various complex vibration states can be created.

Their vibration states are shown in FIGS. 4 to 10. First, when the amplitude of the drive power source 17 is set to O and only the drive power source 11 is driven, the vibration at the point C of the output end 9 vibrates in the axial direction as shown in FIG. 4(d). Therefore, if the relative phase of the drive power source 17 with respect to the drive power source 11 is set to 90 degrees and the amplitude is increased, a horizontally oblong ellipse and a circle are formed as shown in FIG.

Its vibration shape changes to a vertically elongated ellipse. Furthermore, when the relative phase is set to 190 degrees, the rotational direction is reversed and the vibration mode changes as shown in FIGS.

Next, when the amplitude of the drive power source 11 is set to O and only the drive power source 17 is applied, the point C deflects and vibrates in the direction perpendicular to the axis as shown in FIG. 5(d). Therefore, when the amplitude of the drive power source 11 is increased, the amplitude and the relative phase of 90 degrees lead or lag, as shown in Figures (C), (b), (a), or (e).
, (f), and (g), vibration states in which the ellipticity and rotation direction are changed are obtained.

Next, with the amplitude of the drive power source 11 constant, the drive type g17
When the amplitude is increased from 0 while keeping the phase of the vibrations in the same phase, the vibration amplitude increases while changing the inclination angle from the axial direction, as shown in FIGS. 6(a) to (e). Furthermore, when the phase between the open drive power sources is inverted and the amplitude of the drive power source 17 is increased from 0, the inclination angle changes from the axial vibration to the 6th angle as shown in FIGS. 7(,) to (e). The vibration amplitude increases as the vibration is changed in the opposite direction to the diagram.

Next, while keeping the deflection drive signal of the drive power source 17 constant and the phase of the axial drive signal of the drive power source 11 kept in the same phase,
When the amplitude is increased from 0, from Fig. 8(a) to (
As shown in e), the vibration amplitude increases from the vibration in the deflection direction while changing the inclination angle.

Furthermore, when the phase between the open drive power supplies is inverted and the amplitude of the drive power supply 11 is increased from 0, the results shown in FIGS. 9(a) to (e)
As shown in FIG.

Next, if the drive power supplies 11 and 17 are respectively controlled so that the vibration amplitudes in the axial direction and the deflection direction are the same, and the relative phase of the surface drive power supply is set to 0 degrees, as shown in FIG. 10(e),
A linear vibration tilted at 45 degrees with respect to the axis is obtained, but by controlling the relative phase, tilted ellipses, circles, oppositely tilted ellipses, and oppositely tilted straight lines can be created as shown in (d), (c), (b), and (a). is obtained, and if the relative phase is reversed, similarly (f
), vibrations with the rotational direction reversed as shown in (i) are obtained.

In the device shown in FIG. 11, electrodes 34 and 35 and electrodes 36 and 37 are connected to the outer surface electrodes of electrostrictive element plates 32 and 33 provided at the center in the longitudinal direction of a rectangular diaphragm 31 at the center in the axial direction.
The lead terminals 38, 39,
40 and 41 are ultrasonic transducers in which a common lead terminal 42 is further led out from the diaphragm 31, and the lead terminals 39 and 41, and 38 and 40, that is, diagonally located electrodes, are connected in parallel. If the connections are made in the same manner as shown in Figure 2, and the respective drive power supplies 11 and 17 are adjusted to the resonance frequency to set the relative phase to 90 degrees, the vibration mode at the four corners of the diaphragm 31 will be the same at both ends in the width direction as shown by the arrows. This produces elliptical vibration with the direction of rotation reversed.

FIG. 12 is shown to facilitate understanding of the vibration state, in which the maximum displacement state of the diaphragm 31 in the thickness direction is indicated by a chain double-dashed line. In other words, in one half cycle, the right half in the width direction curves upward and the left half curves downward with respect to the central axis, and in the next half cycle, it curves in opposite directions and curves in the axial direction with a phase difference of 90 degrees. is expanding and contracting. However, in order to make the explanation easy to understand, the first-order flexural vibration is exemplified here, but it is determined depending on the configuration of the vibrating body, and higher-order vibrations may be used.

Furthermore, FIG. 13 shows the same configuration as FIG. 11 but with a different combination of lead terminals, with lead terminals 39 and 40.3.
8 and 41 are connected in parallel, and the respective drive power supplies 11 and 17 are adjusted to the resonant frequency to set the relative phase to 90 degrees as shown in Fig. 2. According to the same principle as above, both ends in the width direction are as shown by the arrows. Elliptical vibration is performed uniformly on each surface.

As is clear from the detailed explanation of the principle described above, the vibration state at the axial end face of the diaphragm is such that the combination vibration of the axial direction and the deflection direction, which is a straight line, circle, and ellipse, and their rotational direction are It is possible to freely control the amplitude or relative phase of the deflection direction drive power source whose phase is inverted, and the axial drive power source superimposed thereon, or by the amplitude and relative phase of each of them.

Therefore, the ultrasonic vibrator is configured as described above, and the output end face of the diaphragm is brought into pressure contact with a rotating body such as a rotor or a moving body.
If the vibrator is driven by the above driving method, the rotation direction can be controlled and the optimal driving conditions with the rotating body, i.e., an ellipse that can be driven with the maximum torque with the maximum coefficient of friction and minimum wear, can be achieved. This makes it possible to control the shape of vibration.

An example of constructing a linear motor by using the vibrator shown in FIG. 1 and driving it according to the method of the present invention will be described as follows.

That is, FIG. 14 shows a stepped horn-shaped vibrating body 1 by providing an R step on the output side of the diaphragm in the ultrasonic transducer shown in FIG. When the ultrasonic transducer is controlled in its position as shown by the arrow in the figure and pressed against the surface of the opposing rail R, the ultrasonic transducer moves in the direction of the thick arrow.

In the above embodiment, a vibrator in which the output end is formed into a single shape has been described. A vibrator equipped with an electrostrictive element plate, that is, the patent application No. 60-27164 already filed by the present applicant.
The same applies to all the vibrators described in No. 4 and Japanese Patent Application No. 60-293110.

In the present invention, it goes without saying that the drive power source for controlling each amplitude or relative phase, or each amplitude and relative phase, is the same for both conventionally well-known constant voltage drive and constant current drive. Preferably, the constant voltage drive is applied at a parallel resonant frequency, and the constant current drive is applied at a series resonant frequency. Therefore, the amplitude or relative phase of the drive power source means the amplitude or relative phase of the drive voltage or drive current.

〔Effect of the invention〕

Since the present invention is as described above, it is extremely useful as a drive control method for a vibrator used in an ultrasonic motor.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of an ultrasonic transducer driven and controlled by the method of the present invention, FIG. 2 is a wiring diagram when driving the transducer, and FIG. 3 is for explaining the principle of the method of the present invention. , FIGS. 4 to 10 are diagrams showing the vibration state of the transducer according to the method of the present invention, FIG. 11 is a separate perspective view of the ultrasonic transducer driven and controlled by the method of the present invention, and FIG. FIG. 11 is an explanatory diagram of the vibration state of the vibrator shown in FIG. 11, FIG. 13 is a perspective view of the vibrator shown in FIG. 11 with a different combination of lead terminals, and FIG. Using an ultrasonic transducer,
FIG. 15 is a perspective view of an example of a linear motor driven by the method of the present invention, and FIG. 15 is a perspective view of an example of a conventional ultrasonic motor.

Claims (1)

[Scope of Claims] 1. An ultrasonic vibrator including electrostrictive element plates mounted on both sides of a diaphragm, such that the output end face of the diaphragm generates compound vibration in its axial direction and deflection direction. A method for controlling the drive of an ultrasonic transducer, characterized in that a drive power source having an inverted phase and a superimposed drive power source are applied to each pair of electrodes. 2. A drive control method for an ultrasonic transducer according to claim 1, characterized in that the amplitude or the relative phase, or the amplitude and relative phase of each drive power source is controlled. 3. The ultrasonic transducer drive control method according to claim 1, wherein the relative phase of each drive power source is set to 90 degrees and the amplitude of each is controlled. 4. In an ultrasonic vibrator in which electrostrictive element plates are attached to both sides of a diaphragm, the output end face of the diaphragm is a combination of the axial direction and the deflection direction, and both widthwise ends or axial ends are opposite to each other. A method for controlling the drive of an ultrasonic transducer, characterized in that a drive power source having an inverted phase and a superimposed drive power source are applied to each pair of electrodes so as to form a complex vibration in a direction. 5. The method for controlling the drive of an ultrasonic transducer according to claim 4, characterized in that the amplitude or relative phase of each drive power source, or the amplitude and relative phase of each drive power source is controlled. 6. The ultrasonic transducer drive control method according to item 4, wherein the relative phase of each drive power source is 90 degrees and the amplitude of each is controlled. 7. In an ultrasonic vibrator in which electrostrictive element plates are attached to both sides of a diaphragm, the output end face of the diaphragm is paired such that the output end face of the diaphragm generates a composite vibration in the axial direction and the deflection direction. Both ends of the secondary coil of the transformer are connected to each electrode, and an axial drive power is applied to the midpoint of the transformer's secondary coil, and a flexural drive power is applied to the transformer's primary coil. A method for controlling the drive of a sound wave vibrator. 8. A drive control method for an ultrasonic transducer according to claim 7, characterized in that the amplitude or relative phase of each drive power source, or the amplitude and relative phase of each drive power source is controlled. 9. The ultrasonic transducer drive control method according to claim 7, wherein the relative phase of each drive power source is set to 90 degrees and the amplitude of each is controlled. 10 In an ultrasonic vibrator in which electrostrictive element plates are attached to both sides of a diaphragm, the output end face of the diaphragm is a composite of its axial direction and deflection direction, and both widthwise ends or axially both ends are opposite to each other. Both ends of the secondary coil of the transformer are connected to each pair of electrodes so as to produce compound vibration in the direction, and an axial drive power source is connected to the midpoint of the secondary coil of the transformer.
A method for controlling the drive of an ultrasonic transducer, further comprising applying a deflection direction drive power to the primary coil of the transformer. 11. The ultrasonic transducer drive control method according to claim 10, characterized in that the amplitude or relative phase of each drive power source, or the amplitude and relative phase of each drive power source is controlled. 12. The ultrasonic transducer drive control method according to claim 10, wherein the relative phase of each drive power source is 90 degrees and the amplitude of each is controlled.