JPH0345986B2 - - 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. 15.
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. 15 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 A pair of electrodes are formed on one surface of the electrostrictive element body polarized in the thickness direction by being divided into two in the circumferential direction, and a common electrode is formed on the other surface. A plurality of electrostrictive elements arranged in the direction are provided to form a vibrator having legs divided in the circumferential direction by a number of divisions corresponding to the number of electrode pairs, and a single part is formed between the vibrator and the metal member. One or more of the electrostrictive elements are positioned and integrally clamped and fastened.

Action: A plurality of pairs of electrodes arranged in the circumferential direction are aligned in the circumferential direction, and the electrodes connected in parallel are supplied with alternating current voltage whose relative phase is controlled to each other, alternating current voltage whose relative amplitude is controlled to each other, or a combination of these. By applying an alternating current voltage, it is possible to generate linear vibration, circular vibration, and elliptical vibration in any direction on a plane perpendicular to the direction in which the electrodes are divided in the vibrator.

Embodiment A first embodiment of the present invention will be described based on FIGS. 1 to 11. First, the electrostrictive element 9 shown in FIG. 2 consists of four electrode pairs 10, each electrode pair 10 is arranged in a ring shape in the circumferential direction, and each electrode pair 10 is an electrostrictive element polarized in the thickness direction. Element body 11
A pair of electrodes 13 which are divided into two by an insulating portion 12 are formed on one surface, and a common electrode 14 is formed on the other surface. One electrostrictive element 9 is constructed by combining four such electrode pairs 10.

Next, what is shown in FIG. 3 is an electrode plate 15,
In this electrode plate 15, an electrode portion 16 is formed for each electrode 13 of the electrostrictive element 9, and a terminal 17 is formed in each electrode portion 16. This electrode plate 15 is made of a printed circuit board having copper foil pasted on both sides of a glass epoxy thin plate having a hole 18 in the center.

Thus, the electrostrictive elements 9 were bonded to both sides of the electrode plate 15, the vibrator 19 was bonded to one electrostrictive element 9, and the common terminal 20 was provided to the other electrostrictive element 9. Metal members 21 are joined together with conductive bolts 2 passing through the center.
2 and a nut 23.

The vibrator 19 has a wide groove 25 and a narrow groove 26 toward one side, with the end face being an output end 24.
Thus, the number of leg portions 27 corresponding to the number of the electrode pairs 10 is formed. End surfaces of these leg portions 27 are joined to each common electrode 14 of the electrode pair 10.

Then, the electrodes 13 of each electrode pair 10 are connected in parallel to the electrodes 13 of the electrostrictive element 9, aligned in the circumferential direction, and connected to a drive circuit (not shown) via a terminal 17 and a common terminal 20. has been done.

In such a configuration, a drive control voltage is applied from the drive circuit to the electrostrictive element 9;
For convenience of explanation, FIG. 4 shows a development view developed in the circumferential direction. Here, for the electrodes 13 of the electrode pairs 10, a lead terminal 28 pulled out from the right side of each electrode pair 10 and a lead terminal 29 pulled out from the left side of each electrode pair 10.
is provided. A drive power source that can control the mutual phase is connected between these lead terminals 28, 29 and the common electrode 20, and the drive frequency is adjusted to match the axial resonance frequency.

When this phase difference is set to zero, in-phase parallel drive occurs, and the vibration on the circumferential surface of the output end 24 becomes axial resonant vibration as shown in Figure 5e, similar to a normal vertical vibrator. It vibrates with its posture. Therefore, if the phase of the drive voltage applied to the lead terminal 28 is advanced with respect to the lead terminal 29, the vibration on the circumferential surface of the output end 24 will be an elliptical vibration in the counterclockwise direction that is long in the axial direction, as shown in Fig. 5d. I do. As the phase advance is further increased, the shape changes to an ellipse that is short in the axial direction and long in the direction orthogonal to the axial direction, as shown in FIGS. 5c, b, and a.

Such an operation occurs because the vibrator 19 is deflected not only in the axial direction but also in the circumferential direction due to a phase shift in the expansion and contraction between the right half and the left half of the electrode pair 10 of the electrostrictive element 9, resulting in axial vibration and torsional vibration. This is because a complex resonant vibration is generated, which is synthesized with a phase difference of 90°.

Similarly, lead terminal 2 for lead terminal 29
When the phase of the driving voltage applied to the elliptical oscillator 8 is delayed, the elliptical vibration is reversed clockwise, and as the phase difference increases, the vibration mode changes as shown in FIG. 5 f, g, h, and i.

A case where the present invention is applied to a rotary ultrasonic motor as a device to which such a vibration mode is applied will be explained with reference to FIG. 6. This rotary ultrasonic motor has a disk 30 acting as a rotor pressed into contact with the output end 24 of the vibrator 19. This disk 30
A counterbore hole 31 is formed at the center of the contact surface side with the output end portion 24, and a shaft 32 is formed at the center of the other surface. For example, when the drive voltage is controlled so that the output end 24 vibrates as shown in FIG. 5i, the disk 30 rotates about the shaft 32 in the direction of the arrow 33. If the relative phase is controlled to be as shown in FIG. 5(f), the rotational speed will be slowed down, and if they are in the same phase, the vibration will be only in the axial direction as shown in FIG. 5(e) and will come to rest. Furthermore, if the phase is increased in the opposite direction, the rotational speed of the disk 30 will be increased in the opposite direction to the arrow 33.

Note that what is shown in FIG. 6 is only the principle thereof, and illustrations of mechanical parts such as bearings and pressing devices are omitted.

Such a rotary ultrasonic motor can be driven in both forward and reverse directions by a single vibrator 19, and its ellipticity can be controlled, so wear on the contact surface is minimized and the best contact condition is achieved. Furthermore, the important point is that contact can be made on the entire circumferential surface of the output end 24, and a large drive torque can be obtained with a small surface pressure, which significantly increases the efficiency and reliability. It is something that

Next, in the devices shown in FIGS. 1 and 4, when the phases of the drive voltages applied to the lead terminals 28 and 29 are set in the same phase and the relative amplitude is changed, the peripheral surface of the output end 24 is The vibration mode at this point is a straight line inclined with respect to the axial direction.

That is, first, if the applied voltages are of the same phase and amplitude, the resonant vibration will occur in the axial direction like a normal vertical vibrator as shown in FIG. If it is lowered, it will tilt to the left as shown in Figure 7b, and if the difference is increased, the direction will tilt further as shown in Figure 7a, and,
When the difference is reversed, it tilts in the opposite direction as shown in FIG. 7d and e. Therefore, the tilt angle can be freely controlled by the relative amplitude of the drive voltage.

The operation of the output end face 24 when it is vibrating as shown in Fig. 7e is as shown by dotted lines and arrows in Fig. 8, such as rotating counterclockwise while extending in the axial direction, or clockwise while contracting. It emits rotating, resonant vibrations. Such a vibration mode can be widely used in the field of ultrasonic machining, and is suitable for, for example, drilling and tapping.

Next, when the lead terminals 28 and 29 are driven with a phase difference of 180 degrees, that is, reversed, between the drive voltages, the output end 24 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 28 and 29 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. The lead terminal 2 performs resonance vibration with a phase difference of 180° as a reference.
9, depending on the phase lead/lag of the voltage applied to the lead terminal 28, an elliptical vibration can be generated in the counterclockwise direction long in the circumferential direction as shown in FIG. 9c, or in the clockwise direction long in the circumferential direction as shown in FIG. 9e. When the phase difference is further increased, the elliptical shape changes from b to a in FIG. 9, or from f to g in FIG. 9.

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 as shown in FIGS. 10h to 10 can be obtained.

Although the electrode plate 15 has been described as using a glass epoxy-based printed circuit board, in actual practice, electrodes may be vapor-deposited, plated, or printed on an insulating substrate such as ceramics. It's okay. Furthermore, the electrode plate 15 can be provided with electrodes only on one side and configured with a single electrostrictive element 9.

Furthermore, what is shown in FIG. 11 is a modified example of the electrode plate 15, in which the diameter is made larger than the diameter of the electrostrictive element 9, and eight grooves 35 are formed radially from the center hole 34.
, and after assembly, the connecting portion 3 on the outer periphery of the groove 35 is formed.
6 is cut off to form an independent electrode.

Moreover, what is shown in FIGS. 12 and 13 is a second embodiment of the present invention. The same parts as in the previous embodiment are denoted by the same reference numerals, and the description thereof will be omitted. First, the electrostrictive element 9 is made up of two electrode pairs 10 each having an electrode 13 divided into two parts by an insulating section 12, and each electrode pair 10 has a hole 37 formed in its center. Two such electrostrictive elements 9 are used with an electrode plate 15 in between, and the vibrator 38 has a groove 39 and an exponential step.

Next, what is shown in FIG. 14 is a modification of the electrostrictive element 9, which uses an electrostrictive element main body 11 divided into each electrode 13. Of course, it is a pair of two pieces. These electrostrictive element bodies 11, together with the electrode plates, are held between the vibrator and the metal member, and are tightened and held by a central bolt to be integrated.

In the present invention, the expression "an electrostrictive element 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 and a common electrode is formed on the other side", It includes all the examples shown in the previous embodiments.

Effects of the Invention As described above, the present invention provides an electrode in which a pair of electrodes is formed on one surface of the electrostrictive element body polarized in the thickness direction and is divided into two in the circumferential direction, and a common electrode is formed on the other surface. An electrostrictive element having a plurality of pairs arranged in the circumferential direction is provided to form a vibrator having legs divided in the circumferential direction by a number of divisions corresponding to the number of the electrode pairs, and a connection between the vibrator and the metal member is provided. Since one or more electrostrictive elements are positioned between two vibrators and clamped together, the output terminal can be adjusted by changing the phase and amplitude of the driving voltage to the electrodes. The vibration of the part can be varied in a wide range from linear to elliptical to circular motion.
Furthermore, the direction of rotation can be reversed and any vibration state from longitudinal vibration to torsional vibration can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention;
Figure 2 is a perspective view of the electrostrictive element, Figure 3 is a plan view of the electrode plate, Figure 4 is a developed view, Figure 5 is an explanatory diagram showing the vibration state of the output end, and Figure 6 is a rotating type. 7 is an explanatory diagram showing the vibration state of the output end; FIG. 8 is a perspective view showing the vibration state of the output end; FIGS. 9 and 1.
Figure 0 is an explanatory diagram showing the vibration state of the output end;
12 is a perspective view showing a second embodiment of the present invention, FIG. 13 is a perspective view of the electrostrictive element, and FIG. 14 is a modified electrostrictive element. FIG. 15 is an exploded perspective view showing a conventional example. 9... Electrostrictive element, 10... Electrode pair, 11... Electrostrictive element body, 13... Electrode, 14... Common electrode,
19... Vibrator, 21... Metal member, 27...
leg.

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 a plurality of electrostrictive elements, and a vibrator is formed which has legs that are divided in the circumferential direction by a number of divisions that correspond to the number of electrode pairs and each has an end surface that comes into contact with the electrode pairs, and A metal forming an electrode plate having an electrode portion that contacts each electrode of the electrode pair and each has a terminal, and that contacts the electrostrictive element consisting of the electrode pair arranged in the circumferential direction and is provided with a common terminal. A member is formed, one or more electrostrictive elements and the electrode plate are positioned between the metal member and the vibrator, and the metal member, the electrostrictive element, the electrode plate, and the vibration An ultrasonic transducer characterized in that the metal member and the transducer are electrically connected to each other by a conductive bolt and nut passing through the center of the transducer and clamped and fastened together. 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 a vibrator is formed which has legs divided in the circumferential direction by a number of divisions corresponding to the number of electrode pairs and each having an end surface that abuts each of the electrode pairs, and each electrode of the electrode pairs. forming an electrode plate having electrode portions each having a terminal, and forming a metal member contacting the electrostrictive element comprising electrode pairs arranged in the circumferential direction and having a common terminal; One or more of the electrostrictive elements and the electrode plate are positioned between the metal member and the vibrator, and the center of the metal member, the electrostrictive element, the electrode plate, and the vibrator is penetrated. The metal member and the vibrator are electrically connected and clamped together using conductive bolts and nuts, and the two halves of the electrode pair are aligned in the circumferential direction and placed in parallel. connection,
An ultrasonic transducer characterized in that a drive circuit is provided for applying an alternating current voltage with a controlled relative phase to each of the parallel-connected electrodes. 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 a vibrator is formed which has legs divided in the circumferential direction by a number of divisions corresponding to the number of electrode pairs and each having an end surface that abuts each of the electrode pairs, and each electrode of the electrode pairs. forming an electrode plate having electrode portions each having a terminal, and forming a metal member contacting the electrostrictive element comprising electrode pairs arranged in the circumferential direction and having a common terminal; One or more of the electrostrictive elements and the electrode plate are positioned between the metal member and the vibrator, and the center of the metal member, the electrostrictive element, the electrode plate, and the vibrator is penetrated. The metal member and the vibrator are electrically connected and clamped together using conductive bolts and nuts, and the two halves of the electrode pair are aligned in the circumferential direction and placed in parallel. connection,
An ultrasonic transducer characterized by being provided with a drive circuit that inverts the relative phase of each of the parallel-connected electrodes and applies an alternating current voltage that controls the relative phase. 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 a vibrator is formed which has legs divided in the circumferential direction by a number of divisions corresponding to the number of electrode pairs and each having an end surface that abuts each of the electrode pairs, and each electrode of the electrode pairs. forming an electrode plate having electrode portions each having a terminal, and forming a metal member contacting the electrostrictive element comprising electrode pairs arranged in the circumferential direction and having a common terminal; One or more of the electrostrictive elements and the electrode plate are positioned between the metal member and the vibrator, and the center of the metal member, the electrostrictive element, the electrode plate, and the vibrator is penetrated. The metal member and the vibrator are electrically connected and clamped together using conductive bolts and nuts, and the two halves of the electrode pair are aligned in the circumferential direction and placed in parallel. connection,
An ultrasonic transducer characterized in that a drive circuit is provided for applying an alternating current voltage with a controlled relative amplitude to each of the parallel-connected electrodes. 5. An electrode in which a plurality of pairs of electrodes are arranged circumferentially on one surface of an electrostrictive element body polarized in the thickness direction, each divided into two in the circumferential direction to form a pair of electrodes, and a common electrode formed on the other surface. A strain element is provided, and a vibrator is formed which has legs divided in the circumferential direction by a number of divisions corresponding to the number of electrode pairs and each having an end surface that abuts each of the electrode pairs, and each electrode of the electrode pairs. forming an electrode plate having electrode portions each having a terminal, and forming a metal member contacting the electrostrictive element comprising electrode pairs arranged in the circumferential direction and having a common terminal; One or more of the electrostrictive elements and the electrode plate are positioned between the metal member and the vibrator, and the center of the metal member, the electrostrictive element, the electrode plate, and the vibrator is penetrated. The metal member and the vibrator are electrically connected and clamped together using conductive bolts and nuts, and the two halves of the electrode pair are aligned in the circumferential direction and placed in parallel. connection,
An ultrasonic transducer characterized in that a drive circuit is provided for applying an alternating current voltage with controlled relative phase and relative amplitude to each of the parallel-connected electrodes.