JPH0345987B2 - - Google Patents

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 particularly relates to an ultrasonic vibrator suitable for use in ultrasonic motors, etc. .

BACKGROUND TECHNOLOGY In general, ultrasonic vibrators include a Languevent type vibrator in which a disc-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.

An example of an ultrasonic motor configured with such a unidirectional vibrator is disclosed in Japanese Patent Application Laid-open No. 55-125052.
There is something described in the No. 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 different type of unidirectional vibrator, there is a vibrator as shown in FIG. 11.
That is, the vibrator 3 is formed by integrally fastening the vertical vibrator 1 and the torsional converter 2. 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 via a bolt 6 and a coil spring 7 in a pressed state. Therefore, when the longitudinal vibration generated by the vertical vibrator 1 is applied to the torsional transducer 2, an elliptical vibration is generated in the direction of the arrow at the tip of the beam-like protrusion 5 of the torsional transducer 2, and the rotor 8 in contact with it It rotates clockwise as shown by the arrow. 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. 11 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 the ellipticity is controlled to be optimal for driving and the direction of rotation thereof. That is 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 Problem An electrostrictive element is provided in which a bisected electrode is formed on one side of an electrostrictive element body polarized in the thickness direction, and a common electrode is formed on the other side. Metal materials are integrally fastened to both sides of the electrostrictive element using fasteners, and one of the metal materials forms an output end portion in which at least three or more contact legs are formed radially.

Action By applying AC voltages with different phases, AC voltages with different amplitudes, or a combination of these to the electrodes, linear vibration or circular vibration is generated at the output end on a plane perpendicular to the direction in which the electrodes are divided. ,
Elliptical vibration can be generated in any direction, and three or more contact legs are formed radially at the output end of the metal material, so the contact area of the driven object is large and a large drive torque can be obtained. It is something that can be done.

Embodiment A first embodiment of the present invention will be described based on FIGS. 1 to 9. First, four electrostrictive element bodies 9 are provided which are polarized in the thickness direction and combined to form an annular shape.
On one side, electrodes 11 and 12 are formed by dividing into two parts with an insulating part 10 located at the center as the center, and on the other side, a common electrode 13 is formed as a full-surface electrode, thereby forming an electrostrictive element 14.

Two sets of such electrostrictive elements 14 are prepared, and the electrodes 11 and 12 are opposed to each other with an electrode plate 15 in between,
The insulating tube 16 is inserted through the center. The electrode plate 15
has a radial inter-electrode portion 17 divided into eight equal parts, and an electrode 19 having a terminal portion 18 is formed between these inter-electrode portions 17. Four contact legs 20 are provided on the surface of the common electrode 13 of one electrostrictive element 14.
Output end 2 formed radially into a cross shape
1 is joined. A slit 23 is formed in the metal material 22 in a radial direction in a cross shape, leaving the center part of the slit 23.
A leg portion 24 is formed which is located at the center. Further, a common electrode plate 25 is bonded to the surface of the common electrode 13 of the other electrostrictive element 14, a metal material 26 is bonded to this common electrode plate 25, and these are integrally connected by bolts 27 as fasteners. Fixed. That is, the metal material 26 is formed with a hole 28 through which the bolt 27 is inserted, and the metal material 22 has a threaded portion 2 into which the bolt 27 is screwed.
9 is formed. In this way, the composite vibrator 30 is configured.

Then, the electrodes 11 and 12 and the common electrode 1
3, an electrode plate 15 and a common electrode plate 25 are interposed therebetween, and every other one is connected to a drive control circuit (not shown) via lead terminals 31 and 32.

In such a configuration, the lead terminals 31, 3
2 and the common electrode plate 25 are connected to drive power sources whose phases can be controlled mutually, and the drive frequency thereof is adjusted to the axial resonance frequency. When the phase difference is set to zero, in-phase parallel drive occurs, and the output end 21 vibrates in an axial resonant vibration as shown in FIG. 6d in a vibration mode similar to that of a vertical vibrator.

Therefore, if the phase of the oscillating voltage applied to one lead terminal 31 is advanced with respect to the other lead terminal 32, an elliptical vibration in the counterclockwise direction long in the axial direction is produced as shown in FIG. As the degree of phase is further increased, the shape becomes shorter in the axial direction as shown in b and a, and changes to an elliptical shape that is longer in the direction perpendicular to the axial direction.

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 FIG. 6e, f, and g.

What is shown in FIG. 5 is an example of its use, in which it is used in an ultrasonic motor. That is, the output end 2 of the composite vibrator 30 is placed on the surface 35 of the disk-shaped rotor 34 with the support shaft 33 provided at the center.
This is a pressure-welded version of 1. For example, in the state shown in FIG. 5, the vibration of the output end 21 is in the state g in FIG. 6, and the rotor 34 moves in the direction of the arrow 36. When the relative phase is controlled to take the position shown in FIG. 6e, the moving speed of the rotor 34 becomes slow, and when the rotor 34 is in the same phase as shown in FIG. As the speed increases, the rotor 34 increases its speed in the opposite direction. In this manner, the rotor 34 is driven, resulting in the rotor 34 rotating at a constant speed.

In addition, since a single composite vibrator 30 can be driven in forward and reverse directions and its ellipticity can be controlled, it is possible to drive in the best contact condition with less wear on the contact surface, increasing efficiency and reliability. The sex is enhanced.

Furthermore, when the phases of the drive voltages applied to the lead terminals 31 and 32 are kept in the same phase and their relative amplitudes are changed, the vibration direction of the output end 21 is tilted with respect to the axial direction as shown in FIG. It vibrates in a straight line. That is, when the applied voltages have the same amplitude, the vibrator vibrates resonantly like a normal vertical vibrator, as shown in FIG. When the vibration direction is tilted as shown in FIG. 7b and the difference is further increased, the vibration direction becomes even more tilted as shown in FIG. 7a. Moreover, when the difference is reversed, the slopes are similarly tilted in opposite directions like d and e. These angles of inclination can be freely controlled by the relative amplitudes of the drive voltages.

Further, by simultaneously changing not only the phase difference but also the amplitude of the drive control voltage, extremely diverse complex vibration states can be obtained, and the field of use thereof can be expanded.

Next, when the lead terminals 31 and 32 are driven with a phase difference of 180 degrees, that is, reversed, between the drive voltages, the output end 21 performs torsional resonance vibration. This torsional resonance vibration is considerably lower than the axial resonance frequency, and if the frequency is kept the same, the shape of the device will be smaller.

Such torsional vibration is obtained by combining bending vibrations in the axial direction at the axial ends, but high-order resonance points also occur near the axial resonance frequency.

Therefore, if the phase difference between the drive voltages applied to the lead terminals 31 and 32 is adjusted to 180 degrees, that is, the phase is inverted to a bending resonance frequency close to the axial resonance frequency, a straight line in the circumferential direction as shown in Fig. 8c. However, the lead terminal 3 resonates with a phase difference of 180° as a reference.
2, depending on the phase lead/lag of the voltage applied to the lead terminal 31, an elliptical vibration may be generated in the counterclockwise direction, which is long in the circumferential direction as shown in FIG. 8b, or in the clockwise direction, which is long in the circumferential direction as shown in FIG. 8d. When the phase difference is further increased, the elliptical shape changes from b to a in FIG. 8 or from d to e in FIG. 8.

Furthermore, if the relative amplitude of the drive voltage when tuned to the bending resonance frequency is controlled, linear vibration inclined with respect to the circumferential direction can be obtained as shown in FIGS. 9a to 9e.

Furthermore, what is shown in FIG. 10 is a modified example of the electrode plate 15, in which the diameter is larger than the diameter of the electrostrictive element 14, and eight grooves 3 are formed radially from the center hole 37.
8, and after assembly, the connecting portion 39 on the outer periphery of the groove 38 is cut off to form an independent electrode.

Effects of the Invention The present invention provides an electrostrictive element in which an electrode divided into two parts is formed on one side of the electrostrictive element body polarized in the thickness direction as described above, and a common electrode is formed on the other side. A metal material is integrally fastened to both surfaces of the plurality of electrostrictive elements by a fastener, and an output end portion in which at least three or more contact legs are radially formed is formed on one of the metal materials. By changing the phase and relative amplitude of the driving voltage to the electrodes,
The vibration of the output end can be varied in a wide range from linear to elliptical to circular motion, and the direction of rotation can also be reversed, while the amplitude of one side remains constant. It is easy to change the ellipticity, or to change the amplitude while keeping the ellipticity constant.In particular, since there are multiple contact legs, the contact area with the driven object is large, and the drive force is large. It is possible to obtain torque.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention;
Figure 2 is a perspective view of the electrostrictive element, Figure 3 is a perspective view of the electrode, Figure 4 is a side view, Figure 5 is an exploded perspective view showing how it is used in an ultrasonic motor, and Figures 6 a to g. is an explanatory diagram showing the vibration state of the output end when the relative phase is changed and driven at the axial resonance frequency, Fig. 7a
~e is an explanatory diagram showing the vibration state of the output end when driving by changing the relative amplitude at the axial resonance frequency,
Figures 8 a to e are explanatory diagrams showing the vibration state of the output end when the relative phase is changed at the torsional resonance frequency, and Figures 9 a to e are when the relative amplitude is changed at the torsional resonance frequency. FIG. 10 is a plan view showing a modified example of the electrode plate, and FIG. 11 is an exploded perspective view showing a conventional example. 9... Electrostrictive element body, 11, 12... Electrode, 1
3... Common electrode, 14... Electrostrictive element, 20... Contact leg, 21... Output end, 22, 26... Metal material, 27... Bolt (fastener).

Claims (1)

[Scope of Claims] 1. A pair of electrodes is formed on one surface of an electrostrictive element body polarized in the thickness direction by being divided into two parts in the circumferential direction, and a common electrode is formed on the other surface. A plurality of electrostrictive elements are arranged in the electrode plate, and an electrode plate is formed which has an electrode portion that contacts each electrode of the electrode pairs and is provided with a terminal, and the electrostrictive element is made of the electrode pairs arranged in the circumferential direction. Two metal members are formed in contact with the element, at least one of these metal members is provided with an output end in which at least three or more contact legs are formed radially, and an output end is formed between these metal members. one or more of the electrostrictive elements and the electrode plate, and connect the metal members on both sides with a conductive bolt inserted through the center of the metal member, the electrostrictive element, and the electrode plate. An ultrasonic transducer characterized by being electrically connected and integrally clamped and fastened. 2. An electrode in which a plurality of pairs of electrodes are arranged in the circumferential direction, each of which is divided into two in the circumferential direction to form a pair of electrodes on one surface of the electrostrictive element body polarized in the thickness direction, and a common electrode is formed on the other surface. A strain element is provided, and an electrode plate is formed that has an electrode portion that contacts each electrode of the electrode pair and is each provided with a terminal, and two electrode plates that contact the electrostrictive element are formed of electrode pairs arranged in a circumferential direction. forming an output end in which at least three or more contact legs are formed radially on at least one of these metal materials, and one or more contact legs are formed between these metal materials. The electrostrictive element and the electrode plate are positioned, and the metal members on both sides are electrically connected by a conductive bolt inserted through the center of the metal member, the electrostrictive element, and the electrode plate. 1. An ultrasonic transducer comprising a drive circuit that is integrally clamped and fastened and applies a drive voltage with a controlled relative phase to the electrodes of the electrostrictive element. 3. An electrode in which a plurality of pairs of electrodes are arranged in the circumferential direction, each of which is divided into two in the circumferential direction to form a pair of electrodes on one surface of the electrostrictive element body polarized in the thickness direction, and a common electrode is formed on the other surface. A strain element is provided, and an electrode plate is formed that has an electrode portion that contacts each electrode of the electrode pair and is each provided with a terminal, and two electrode plates that contact the electrostrictive element are formed of electrode pairs arranged in a circumferential direction. forming an output end in which at least three or more contact legs are formed radially on at least one of these metal materials, and one or more contact legs are formed between these metal materials. The electrostrictive element and the electrode plate are positioned, and the metal members on both sides are electrically connected by a conductive bolt inserted through the center of the metal member, the electrostrictive element, and the electrode plate. 1. An ultrasonic transducer comprising a drive circuit which is integrally clamped and clamped and which applies a drive voltage with a controlled relative amplitude to the electrodes of the electrostrictive element. 4. An electrode in which a plurality of electrode pairs are arranged in the circumferential direction, each of which is divided into two in the circumferential direction to form a pair of electrodes on one surface of the electrostrictive element body polarized in the thickness direction, and a common electrode is formed on the other surface. A strain element is provided, and an electrode plate is formed that has an electrode portion that contacts each electrode of the electrode pair and is each provided with a terminal, and two electrode plates that contact the electrostrictive element are formed of electrode pairs arranged in a circumferential direction. forming an output end in which at least three or more contact legs are formed radially on at least one of these metal materials, and one or more contact legs are formed between these metal materials. The electrostrictive element and the electrode plate are positioned, and the metal members on both sides are electrically connected by a conductive bolt inserted through the center of the metal member, the electrostrictive element, and the electrode plate. 1. An ultrasonic transducer comprising a drive circuit that is integrally clamped and clamped and applies a drive voltage with controlled relative phase and relative amplitude to the electrodes of the electrostrictive element.