JPS63214381A - Ultrasonic vibrator and drive control method thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an ultrasonic vibrator that generates complex vibrations in arbitrary directions, and is particularly suitable for use in ultrasonic motors, ultrasonic vibration cutting devices, ultrasonic cutters, etc. The present invention relates to a suitable ultrasonic transducer and its drive control method.

Conventional technology Generally speaking, ultrasonic vibrators include a Langevin type vibrator in which a disk-shaped electrostrictive element is sandwiched between two metal bodies and resonate as one, and a π-type vibrator in which a ferrite magnetostrictive material is molded into a cylindrical or π-shape. Vibrators are often used.

In terms of vibration directions, there are vertical vibrators that vibrate in the axial direction and torsional vibrators that torsionally vibrate symmetrically in the axial direction. These vibrators are unidirectional vibrators that generate vibrations in a single direction, that is, only in the axial direction or only in the torsional direction.

As an example of an ultrasonic motor configured with such a unidirectional vibrator, there is a vibrating piece type vibrator described in Japanese Patent Application Laid-Open No. 55-125052. That is, a vibrating piece is provided at the output end of an axial vibrator, and the vibrating piece is pressed against the rotor with the normal line of the joint surface of a movable member such as a rotor being slightly inclined with respect to the axial direction of the vibrator. As a result, the tip of the vibrating piece vibrates elliptically, causing the rotor to undergo frictional vibration. Such a vibrating piece type has the disadvantage that the contact portion between the vibrating piece and the rotor is subject to significant wear and also generates a large amount of noise.

As a method different from the unidirectional oscillator like 2,
There is a vibrator as shown in FIG. That is, the vertical vibrator 1 and the torsion converter 2 are integrally fastened together to form the vibrator 3.
is formed. A wide groove 4 is formed on one surface of the torsion converting body 2, and a beam-shaped protrusion 5 formed at a certain angle with the groove 4 is formed on the other surface.

A rotor 8 is attached to the torsion converter 2 in a pressed state via a bolt 6, a coil spring 7, and a thrust bearing 9.

Therefore, when the longitudinal vibration generated by the vertical vibrator 1 is applied to the torsional transducer 2, an elliptical vibration is generated at the tip of the beam-like protrusion 5 of the torsional transducer 2 in the direction of the arrow, and the rotor 8 in contact with it is moved in the direction of the arrow. It rotates counterclockwise. Therefore, an efficient ultrasonic motor can be constructed.

Problems to be Solved by the Invention In contrast to the vibrating piece type using a unidirectional vibrator, the vertical torsion conversion type shown in FIG. 8 is expected to solve the drawbacks of the vibrating piece type. The ellipticity of the elliptic vibration, which is the vibration state of the output end, is uniformly determined by the shape of the torsion converter 2, and it is difficult to control the ellipticity to the optimum ellipticity for driving and the direction of rotation. It's impossible. That is, in both cases, the rotor is driven only in a single direction, and furthermore, it is not possible to control the rotor to obtain the elliptical shape necessary to efficiently drive the rotor at maximum torque with little wear on the contact surface.

Means for Solving the Problems An electrostrictive element is provided in which an electrode is divided into two parts with a dividing part as a border, one side is formed, a common electrode is formed on the other side, and the polarization direction is reversed for each electrode. A metal material is integrally fastened to both sides of the electrostrictive element or plurality of electrostrictive elements using a fastener.

Action By applying an AC voltage, an AC voltage with different phases to each other, an AC voltage with different amplitudes to each other, or a combination of these voltages to each electrode 4, a surface perpendicular to the direction in which the electrodes are divided is applied to the output end. It generates complex movements such as linear vibration, circular vibration, and elliptical vibration in any direction.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4. First, the electrode 11 is divided into two parts with the dividing part 1o as a border.
．． A Marugame strain element 14 is provided, in which a common electrode 13 is formed on one surface and a common electrode 13 is formed on the other surface, and the polarization direction is reversed for each of the electrodes 11 and 12.

Two such electrostrictive elements 14 are prepared, and the electrode 1 is placed between two U-shaped electrode plates 15 and 16 with their divided portions 10 aligned and the directions of residual polarization facing each other.
1. 12 are stacked one on top of the other, and the insulating tube 17 is inserted through the center. A metal material 19 having a thin output end 18 and an exponential step is bonded to the surface of the common electrode 13 of one electrostrictive element 14 , and the common electrode 13 of the other electrostrictive element 14 is A common electrode plate 20 is bonded to the surface, a metal material 21 is bonded to the common electrode plate 20, and these are integrally fixed by bolts 22 as fasteners.

That is, the metal material 21 is formed with a hole 23 through which the bolt 22 is inserted, and the metal material 19 is formed with a threaded portion 24 into which the bolt 22 is screwed. In this way, the composite vibrator 25 is configured.

Next, a drive control circuit (not shown) is connected to the electrodes 11.12 and the common electrode 13 via electrode plates 15.16 and a common electrode plate 20.

In such a configuration, a drive power source whose phase can be controlled is connected to the electrode plates 15 and 16 of the common electrode plate 2o, and the drive frequency thereof is adjusted to the deflection resonance frequency. When driving with the phase difference set to zero, the same excitation voltage is applied to both types of strain elements 14a and 14b, so when one of them is extended, the other is contracted and flexurally vibrates, causing the output end 18 of the As shown in Figure 1(d), a linear motion is performed in a direction perpendicular to the axis. Therefore, if the phase of the driving voltage applied to one electrode plate 15 is advanced relative to the other electrode plate 16, a long counterclockwise elliptical vibration is performed in the deflection direction as shown in FIG. 1(C). When the degree of phase advance is further increased, the shape changes to an elliptical shape that is shorter in the deflection direction and longer in the axial direction, as shown in (b) and (a). Similarly, when the phase is delayed, the direction of elliptical vibration is reversed clockwise, and as the phase difference increases, the vibration mode changes as shown in FIGS. 1(e), (f), and (g).

Furthermore, when the relative phase of each excitation voltage applied to the electrode plates 15 and 16 is set to zero and the relative amplitude thereof is changed, the vibration state of the output end 18 changes as shown in FIGS. 1(h), (i), and (k).
It vibrates in a straight line inclined to the direction of deflection (Ω). That is, when the applied voltages have the same amplitude, resonance vibration occurs in the direction perpendicular to the axis as shown in FIG. If the vibration direction is tilted as shown in FIG. 1(i) and the difference is further increased, the vibration direction becomes even more tilted as shown in FIG. 1(h). Moreover, if the difference is reversed, it is similarly shown in Figure 1 (k
) Tilt in the opposite direction as shown in (1). These angles of inclination can be freely controlled by the relative amplitudes of the drive voltages.

Next, the drive frequency is set to the axial resonance frequency, and 1
Drive voltages with a phase difference of 80 degrees are applied to each electrode plate 15.
16, the electrostrictive element 14a.

14b expands and contracts at the same time to perform resonant vibration in the axial direction as shown in FIG. If the phase difference is advanced or delayed with respect to 180 degrees, then Figure 1 (m) to (
o), (q) to (s), the rotational direction and ellipticity are changed to perform elliptic vibration. Furthermore, when the phase difference is set to 180 degrees and the relative amplitude is changed, linear vibration occurs with the slope changing as shown in Figure 1 (t), (u), (w), and (x) depending on the magnitude and polarity. .

Furthermore, if we change the relative phase and relative amplitude simultaneously,
The vibration state is a tilted elliptical vibration in which the elliptical vibration is tilted, and the ellipticity, inclination angle, rotation direction, and magnitude can be freely controlled by the relative phase and amplitude of each drive voltage.

When such a vibrator is operated only by vibration in the axial direction or in the flexural direction, its resonance frequency may be used. When used as a compound vibration, it is most preferable that the axial resonance frequency and the flexural resonance frequency match under the load conditions used, but it is structurally difficult to make them completely match, and furthermore, within a certain range. For example, 1 to 2
A difference of % does not pose a practical problem. therefore,
The axial or flexural resonant frequencies in the foregoing description are preferred frequencies and are shown for ease of understanding and are not limited thereto.
It is equally applicable to any resonance frequency.

In addition, in cases where vibrations in the direction perpendicular to the axis (flexural vibrations) are required, such as ultrasonic cutters and ultrasonic vibration cutting devices, which will be described later, the drive circuit can be simplified because the drive circuit can be driven with the same excitation voltage. be done.

Next, what is shown in FIG. 4 is a modified example of the electrostrictive element 14 in this embodiment. and an electrode 28 and a common electrode 29 are formed on the other side. Then, the two are assembled with a certain interval between them, with the gap between them serving as a dividing part.

Therefore, what is shown in FIGS. 5 to 7 is an application example of the ultrasonic transducer explained in the above embodiment, and the same parts as those explained in FIGS. 1 to 4 are denoted by the same reference numerals. , the explanation is also omitted.

First, the one shown in FIG. 5 is used as an ultrasonic motor. That is, the output end 18 of the composite vibrator 25 is pressed against the surface 32 of a disk-shaped rotor 31 with the support shaft 30 provided in the center. Therefore, for example, if the vibration of the output end 18 is set to the state (S) in FIG.
The rotor 31 rotates in the direction of the arrow. Then, if the relative phase is controlled to take the position shown in FIG. 1(g), the rotor 3
The rotational speed of the rotor 31 becomes slower, and if it is an axial vibration as shown in Fig. 1(p), it becomes stationary, and if the phase difference of the drive voltage is increased in the opposite direction, the rotor 31 increases its speed in the opposite direction. Let me go. In this manner, the rotor 31 is driven with its rotation speed and rotation direction controlled.

In addition to the type of ultrasonic motor that performs rotational motion as described above, if a linear movable body is used in place of the rotor 31, the linear movable body can be relatively linearly driven. That is, if the transducer side is fixed, the linear movable body moves linearly, and if the linear movable body is fixed, the transducer side moves linearly. In addition, since it is possible to drive in both forward and reverse directions with the - number of composite vibrators 25 and to control the ellipticity, it is possible to drive in the best contact condition with less wear on the contact surface, and to improve its efficiency. Reliability is enhanced.

Next, what is shown in FIG. 6 is an example of use as a cutter. That is, the metal material 33 is provided with a knife-shaped cutting edge 34 at its tip, and the electrode plates 15 and 16 are provided with a common electrode plate 2.
By applying the same driving voltage to 0, the vibrator 25 bends and vibrates, and the tip of the cutting blade 34 vibrates linearly in a direction perpendicular to the axis as shown by an arrow 35. While ordinary ultrasonic cutters have the effect of improving sharpness through axial vibration,
Since this cutter vibrates in a direction perpendicular to the axis, the blade vibrates in the cutting direction relative to the object to be cut, which further improves the effect of ultrasonic vibration.

Next, the example shown in No. 7 @ is an example of use in a lathe that performs ultrasonic vibration cutting. That is, the composite vibrator 25 has one wavelength in its axial direction, and a cutting tool 36 is fixed to the output end. Since the compound vibrator 25 has a small diameter from the tip to the first node, the deflection vibration displacement is expanded, and the cutting tool 36 performs a large resonant vibration in the vertical direction in FIG. 7, and moves in the direction of the arrow. Vibration cutting is performed by pressing the vibration against the rotating workpiece 37.

Since the cutting tool 36 is provided at one end of the compound vibrator 25 in this way, not only does the vertical vibrator in the conventional vibration cutting device become unnecessary, but the overall length is short and a large amplitude expansion ratio can be achieved. is made more compact, and if the nodes of flexural vibration are held at points, the vibrating body can be fixed and replaced easily and reliably, and highly effective driving can be performed without vibration loss.

Effects of the Invention The present invention provides an electrostrictive element in which, as described above, an electrode is divided into two parts with one dividing part as a boundary, an electrode is formed on one surface, a common electrode is formed on the other surface, and the polarization direction is reversed for each of the electrodes. Since the metal material is integrally fastened to both sides of one or more of the electrostrictive elements using fasteners, each electrode can receive the same AC voltage, AC voltages with different phases, and amplitudes of each other. By applying different AC voltages or a combination of these AC voltages, complex motions such as linear vibration, circular vibration, and elliptical vibration can be generated in any direction at the output end on a plane perpendicular to the direction in which the electrodes are divided. Furthermore, the direction of rotation, ellipticity, angle of inclination, etc. can be freely controlled.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal side view showing an embodiment of the present invention, Fig. 2 is a perspective view of an electrostrictive element, Fig. 3 is a perspective view of an electrode, and Fig. 4 is a perspective view showing a modification of the electrostrictive element. , FIG. 5 is a perspective view showing a state in which the ultrasonic motor is used. Fig. 6 is a perspective view showing how it is used in an ultrasonic cutter, Fig. 7 is a side view showing how it is used in an ultrasonic cutting device, and Fig. 8 is an exploded perspective view showing an example of a conventional ultrasonic motor. be. 10... Division part, 11.12... Electrode, 13...
Common electrode, 14...Electrostrictive element, 19.21...Metal Murayama Nobuhito Taga Electric Co., Ltd. Figure 37'' 5 countries Figure 36

Claims (1)

[Scope of Claims] 1. An electrostrictive element is provided in which an electrode is divided into two parts with a dividing part as a border, and a common electrode is formed on one surface, and the polarization direction is reversed for each of the electrodes. An ultrasonic transducer characterized in that a metal material is integrally fastened to the screen of one or more of the electrostrictive elements using a fastener. 2. An electrostrictive element is provided in which an electrode is divided into two parts with the dividing part as a border, and a common electrode is formed on the other surface, and the polarization direction is reversed for each electrode, and one or more of the above-mentioned Ultrasonic waves characterized in that a metal material is integrally fastened on both sides of an electrostrictive element using fasteners, and a driving voltage of the same amplitude in the same phase or in opposite phase is applied to the electrodes of the electrostrictive element. Vibrator drive control method. 3. An electrostrictive element is provided in which an electrode is divided into two parts with the dividing part as a border, and a common electrode is formed on the other surface, and the polarization direction is reversed for each of the electrodes, and one or more of the above-mentioned Ultrasonic waves characterized in that metal materials are integrally fastened on both sides of an electrostrictive element using fasteners, and the electrostrictive element is driven by applying a driving voltage with a controlled relative phase to the electrodes of the electrostrictive element. Vibrator drive control method. 4. An electrostrictive element is provided in which an electrode is divided into two parts with the dividing part as a boundary, and a common electrode is formed on the other surface, and the polarization direction is reversed for each of the electrodes, and one or more of the above-mentioned Ultrasonic waves characterized in that metal materials are integrally fastened to both sides of an electrostrictive element using fasteners, and the electrostrictive element is driven by applying a driving voltage with a controlled relative amplitude to the electrodes of the electrostrictive element. Vibrator drive control method. 5. An electrostrictive element is provided, in which an electrode is divided into two parts with the dividing part as a border, and a common electrode is formed on one side, and the polarization direction is reversed for each electrode, and one or more of the above-mentioned electrodes are provided. Metal materials are integrally fastened to both sides of the electrostrictive element using fasteners, and the electrostrictive element is driven by applying a driving voltage with controlled relative phase and relative amplitude to the electrodes of the electrostrictive element. A method for controlling the drive of an ultrasonic transducer.