JPS62155782A - Ultrasonic vibrator and drive control method thereof - Google Patents

Abstract

PURPOSE:To increase a contact area with a rotor, and to reduce driving torque per unit contact area by connecting the end sections of a plurality of vibration diaphragms to a discoid shape. CONSTITUTION:Disks 12, 13 are mounted integrally at both end sections in the axial direction of vibration diaphragms 11 uniformly arranged in the circumferential direction radially. Electrostrictive element plates 14 polarized in the thickness direction are fitted on both side surfaces of each diaphragm 11. Each electrostrictive element plate 14 set up on one sides and the other sides of respective diaphragm 11 are connected in parallel and lead terminals 15, 16 are lead out, and a common lead terminal 17 is lead out of the diaphragms 11, thus constituting an ultrasonic vibrator A.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is an ultrasonic vibrator that generates a composite vibration that is a combination of axial vibration and torsional vibration, and is particularly suitable for ultrasonic motors. This invention relates to a sound wave vibrator and its drive control method.

[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 friction with a rotating body or moving body such as a rotor. 2. Description of the Related Art Ultrasonic motors are known that drive the rotating body through contact.

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
A rotating shaft of a vibrating piece, in which a diaphragm provided on one end surface of one or more ultrasonic transducers and one end surface of a rotating shaft are arranged to face each other, and the two have an inclination angle with respect to the axial direction of the rotating shaft. Or by forming it integrally with either one of the diaphragms,
It is characterized by converting the reciprocating motion of an ultrasonic transducer into rotational motion of a rotary shaft, and a vibrating piece is provided at the output end of the axial transducer, and the vibration of the joint surface of a movable member such as a rotor is When the wire is slightly inclined to the axis of the vibrator and pressurized, the tips of the two vibrating pieces generate elliptical vibration, which frictionally drives a movable member such as a rotor.

[Problem that the invention seeks to solve]

However, in conventional ultrasonic motors such as those mentioned above, the elliptical vibration mode is uniformly determined depending on the structure of the conversion member, and it is necessary to control the rotation direction and the optimum driving conditions with the movable member, that is, the maximum It is not possible to control an elliptical shape that drives with maximum torque with a friction coefficient and minimum wear.

[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 the configuration of the ultrasonic transducer is that the axes of a plurality of diaphragms are arranged radially evenly in the circumferential direction. Both ends of the diaphragm are connected together in a disk shape, and electrostrictive element plates polarized in the thickness direction are attached to all both sides of the diaphragm or to appropriate sides of the diaphragm, and one side of the diaphragm and The electrostrictive element plates mounted on the other side are connected in parallel to lead out lead terminals, and a common lead terminal is led out from the diaphragm, and a drive control method thereof. The configuration is such that a driving power source capable of mutually controlling the phase and amplitude is connected between the lead terminal and the common lead terminal of the ultrasonic transducer, and the relative phase, relative amplitude, or relative phase and relative phase is connected to the lead terminal. It is characterized in that it is driven by applying a driving electric current whose amplitude is controlled.

[For production]

That is, in the present invention, electrostrictive element plates polarized in the thickness direction are attached to both sides of a plurality of diaphragms arranged radially evenly in one circumferential direction and integrally connected at both ends in the axial direction in a disk shape. , by dividing the electrostrictive element plate into two blocks according to the side where it is attached to the diaphragm, and applying a driving voltage with controlled relative phase or relative amplitude or relative phase and relative amplitude to the electrodes of these blocks, It is possible to generate complex vibrations, that is, linear vibrations, circular vibrations, and elliptical vibrations in any direction at the output end.

〔Example〕

Next, embodiments of the present invention will be described, but prior to this description, the principle of generating complex vibrations will be explained as follows.

What is shown in FIG. 2 is an electrostrictive element plate 2 and 3 that is polarized in the thickness direction and provided with electrodes on both sides of the central part of a rectangular plate-shaped vibrating body l made of an elastic body such as metal. are bonded with conductive adhesive or the like, and lead terminals 6 and 7 connected by soldering etc. are drawn out from one electrode 4 of the electrostrictive element plate 2 and one electrode 5 of the electrostrictive element plate 3. ,
The other electrode of each electrostrictive element plate 2 and 3 is connected to the vibrating body 1
It is electrically connected to and taken out as the 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 vibrating body 1. As is well known, when adjusting the frequency,
Both end surfaces 9 and 10 of the vibrating body 1 resonate in the axial direction with maximum displacement.

FIG. 3 is a side view of the vibrator shown in FIG. 2 and shows the vibration state of one end surface 9 of the vibrating body l, and the vibration state in the above-mentioned axial resonant vibration state is expressed as d. .

In the above vibrator, a drive power source whose phase can be controlled mutually is connected between the lead terminals 6 and 7 and the common lead terminal 8, and the drive frequency is adjusted to the axial resonance frequency. When the phase of the drive voltage applied to the lead terminal 7 is advanced with respect to the drive voltage applied to the lead terminal 6, an elliptical vibration is generated in the clockwise direction with the long axis in the axial direction as shown in (e), and the phase difference is increased. As the phase difference increases, the vibration becomes circular as shown in (b), and as the phase difference is further increased, the vibration changes to an elliptical shape with the short axis in the axial direction as shown in (a).

Conversely, if the phase of the lead terminal 7 is delayed, as the phase difference increases, the rotation direction is reversed counterclockwise as shown in (e), (f), and (g), and the same as above. As a result, the vibrational state changes.

On the other hand, in the vibrator shown in FIG. 2, if the phase difference of the AC voltages applied to the lead terminals 6 and 7 is reversed by 180 degrees, and the frequency is matched to the deflection vibration frequency, the end face of the diaphragm l 9 and 1o vibrate linearly in the direction of deflection, that is, in the direction perpendicular to the axis, as indicated by d' in FIG.

Therefore, if the phase difference between the AC voltages applied to the lead terminals 6 and 7 is further advanced or delayed based on the 180 degree phase difference, the deflection will be as shown in (e') or (e'). When the major axis is elliptical vibration in the clockwise or counterclockwise direction, and the phase difference is further increased, (b'), (
a') or (f'L (g')).

The present invention applies the above principle, and FIG. 1 shows an example of the ultrasonic transducer of the present invention.

That is, the one shown in FIG. 1 has disks 12 and 13 at both axial ends of a diaphragm 11 that is arranged radially evenly in the circumferential direction.
are provided integrally, and electrostrictive element plates 14 polarized in the thickness direction are attached to both sides of each diaphragm 11. The respective electrostrictive element plates provided on the left side) are connected in parallel to lead out lead terminals 15 and 16.

Further, this is an ultrasonic transducer A according to an example of the present invention in which a common lead terminal 17 is led out from a diaphragm 11.

The ultrasonic transducer A configured as described above has a driving power source that can mutually control the phase and amplitude connected between the lead terminals 15 and 16 and the common lead terminal 17, and the driving frequency is changed in the axial direction. Alternatively, by adjusting the resonant frequency in the deflection direction and controlling its relative phase and relative amplitude, the third
As shown in the figure and FIG. 4, since the output end face of each diaphragm 11 vibrates, the flexural vibration is combined with the torsional vibration in one direction on the circumference, and for example, as shown by the arrow in the figure, one circular plate 12
The output end face 18 of vibrates, and the vibration mode can be controlled arbitrarily.

That is, the vibration state at the output end surface 18 of the disk 12 is determined by the phase relationship of the AC voltage applied to each electrode between a straight line and its direction, the rotation direction and ellipticity of a circle and an ellipse, on a plane including the axial direction and the torsional direction. It can be freely controlled by adjusting the amplitude relationship.

Therefore, when the above-mentioned vibration is applied to an ultrasonic motor, for example, the rotational direction and rotational speed of a rotating body or the moving direction and moving speed of a moving body can be controlled by controlling the moving direction amplitude and rotational speed of the elliptical vibration. It is easy to control, and by controlling the vibration state to maximize the friction coefficient of the contact surface and minimize wear, it is possible to generate the maximum torque with high reliability.

Furthermore, if the relative phase and relative amplitude of the drive voltage applied to the lead terminals are simultaneously controlled, elliptical vibration with an axis inclined with respect to the axial direction can be obtained, and the same effect as described above can be obtained.

Of course, the shape and thickness of the diaphragm and the output end can be changed as appropriate, and in the embodiment, a center hole is provided in the center of the disk 12, which corresponds to the axial center. However, this disk 12 may be solid.

Further, the attachment of the electrostrictive element plate 14 to the diaphragm 11 is not limited to the central part in the axial direction, but may be installed at various locations depending on the vibration distribution. Although the strain element plate is attached, the present invention does not necessarily require that the electrostrictive element plate be attached to all the diaphragms. For example, the number of diaphragms may be an even number of 4 or more, and an electrostrictive element plate may be attached to every other diaphragm, or one of the adjacent diaphragms may be attached to one side (for example, on the right side in the figure). ), and the other diaphragm has the other side (
For example, the electrostrictive element plate may be attached to the left side of the figure.

〔Effect of the invention〕

The present invention is as described above, and the ultrasonic transducer of the present invention includes:
Since the ends of multiple diaphragms are connected in a disk shape, if this is applied as a rotary ultrasonic motor, the contact area with the rotor will be large and the driving torque per unit contact area will be small, reducing wear. If the vibrator is driven by the driving method of the present invention, the rotational speed and direction of the rotating body can be easily controlled, making it extremely useful.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of the ultrasonic transducer of the present invention, and FIGS. 2 to 4 are for illustrating the principle of the present invention. 11... Vibration plate, 12.13... Disc, 14...
Electrostrictive element plate.

Claims (1)

[Scope of Claims] 1. Both axial ends of a plurality of diaphragms arranged radially evenly in the circumferential direction are integrally connected in a disc shape, and both sides of all the diaphragms or appropriate diaphragms are An electrostrictive element plate polarized in the thickness direction is attached to the side surface, and the electrostrictive element plates attached to one side and the other side of the diaphragm are connected in parallel to lead out lead terminals, and from the diaphragm. An ultrasonic transducer characterized by having a common lead terminal. 2. Both axial ends of a plurality of diaphragms arranged radially evenly in the circumferential direction are integrally connected in a disc shape, and on both sides of the diaphragms or on the side of an appropriate diaphragm, in the thickness direction. Attach a polarized electrostrictive element plate, connect each electrostrictive element plate attached to one side and the other side of the diaphragm in parallel to lead out lead terminals, and lead out a common lead terminal from the diaphragm. A driving power source capable of mutually controlling the phase and amplitude is connected between the lead terminal and the common lead terminal of the ultrasonic transducer consisting of 1. A method of driving an ultrasonic transducer, characterized in that the ultrasonic transducer is driven by applying a drive voltage of